piperidines and repaglinide

Repaglinide is an antidiabetic drug that works by stimulating insulin secretion from pancreatic beta cells. Repaglinide is practically insoluble in water with a water solubility of 34 μg/mL at 37°C, and it has a high absorption rate from the gastrointestinal tract following oral administration since the log P value of repaglinide is 3.97. The low aqueous solubility and the high permeability of repaglinide represent a typical behavior for drugs that belong to class II Biopharmaceutical Classification System (BCS II). Managing type-2 diabetes mellitus with repaglinide is considered a burdensome therapy, as it requires frequent dosing of repaglinide before each meal to maintain its therapeutic plasma concentration due to its short plasma half-life of approximately one hour. Hence the present review aims to discuss thoroughly the various approaches investigated in recent years to develop drug delivery systems that improve oral delivery of repaglinide, including nanoemulsions, solid lipid nanoparticles, nanostructured lipid carriers, sustained-release hydrophilic matrix, floating microspheres, and nanocomposites.

Topics: Carbamates; Delayed-Action Preparations; Drug Delivery Systems; Liposomes; Nanoparticles; Piperidines

Worldwide, there is an increasing incidence of type 2 diabetes mellitus (T2DM). Metformin is still the recommended first-line glucose-lowering drug for people with T2DM. Despite this, the effects of metformin on patient-important outcomes are still not clarified.. To assess the effects of metformin monotherapy in adults with T2DM.. We based our search on a systematic report from the Agency for Healthcare Research and Quality, and topped-up the search in CENTRAL, MEDLINE, Embase, WHO ICTRP, and ClinicalTrials.gov. Additionally, we searched the reference lists of included trials and systematic reviews, as well as health technology assessment reports and medical agencies. The date of the last search for all databases was 2 December 2019, except Embase (searched up 28 April 2017).. We included randomised controlled trials (RCTs) with at least one year's duration comparing metformin monotherapy with no intervention, behaviour changing interventions or other glucose-lowering drugs in adults with T2DM.. Two review authors read all abstracts and full-text articles/records, assessed risk of bias, and extracted outcome data independently. We resolved discrepancies by involvement of a third review author. For meta-analyses we used a random-effects model with investigation of risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We assessed the overall certainty of the evidence by using the GRADE instrument.. We included 18 RCTs with multiple study arms (N = 10,680). The percentage of participants finishing the trials was approximately 58% in all groups. Treatment duration ranged from one to 10.7 years. We judged no trials to be at low risk of bias on all 'Risk of bias' domains. The main outcomes of interest were all-cause mortality, serious adverse events (SAEs), health-related quality of life (HRQoL), cardiovascular mortality (CVM), non-fatal myocardial infarction (NFMI), non-fatal stroke (NFS), and end-stage renal disease (ESRD). Two trials compared metformin (N = 370) with insulin (N = 454). Neither trial reported on all-cause mortality, SAE, CVM, NFMI, NFS or ESRD. One trial provided information on HRQoL but did not show a substantial difference between the interventions. Seven trials compared metformin with sulphonylureas. Four trials reported on all-cause mortality: in three trials no participant died, and in the remaining trial 31/1454 participants (2.1%) in the metformin group died compared with 31/1441 participants (2.2%) in the sulphonylurea group (very low-certainty evidence). Three trials reported on SAE: in two trials no SAE occurred (186 participants); in the other trial 331/1454 participants (22.8%) in the metformin group experienced a SAE compared with 308/1441 participants (21.4%) in the sulphonylurea group (very low-certainty evidence). Two trials reported on CVM: in one trial no CVM was observed and in the other trial 4/1441 participants (0.3%) in the metformin group died of cardiovascular reasons compared with 8/1447 participants (0.6%) in the sulphonylurea group (very low-certainty evidence). Three trials reported on NFMI: in two trials no NFMI occurred, and in the other trial 21/1454 participants (1.4%) in the metformin group experienced a NFMI compared with 15/1441 participants (1.0%) in the sulphonylurea group (very low-certainty evidence). One trial reported no NFS occurred (very low-certainty evidence). No trial reported on HRQoL or ESRD. Seven trials compared metformin with thiazolidinediones (very low-certainty evidence for all outcomes). Five trials reported on all-cause mortality: in two trials no participant died; the overall RR was 0.88, 95% CI 0.55 to 1.39; P = 0.57; 5 trials; 4402 participants). Four trials reported on SAE, the RR was 0,95, 95% CI 0.84 to 1.09; P = 0.49; 3208 participants. Four trials reported on CVM, the RR was 0.71, 95% CI 0.21 to 2.39; P = 0.58; 3211 participants. Three trial reported on NFMI: in two trial. There is no clear evidence whether metformin monotherapy compared with no intervention, behaviour changing interventions or other glucose-lowering drugs influences patient-important outcomes.

Topics: Adult; Carbamates; Cardiovascular Diseases; Cause of Death; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Glucagon-Like Peptide 1; Humans; Hypoglycemic Agents; Insulin; Metformin; Myocardial Infarction; Piperidines; Quality of Life; Randomized Controlled Trials as Topic; Stroke; Sulfonylurea Compounds

The Cystic Fibrosis Foundation recommends both short-term and long-acting insulin therapy when cystic fibrosis-related diabetes (CFRD) has been diagnosed. Diagnosis is based on: an elevated fasting blood glucose level greater than 6.94 mmol/L (125 mg/dL); or oral glucose tolerance tests greater than 11.11 mmol/L (200 mg/dL) at two hours; or symptomatic diabetes for random glucose levels greater than 11.11 mmol/L (200 mg/dL); or glycated hemoglobin levels of at least 6.5%. This is an update of a previously published review.. To establish the effectiveness of insulin and oral agents for managing diabetes in people with cystic fibrosis in relation to blood sugar levels, lung function and weight management.. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also handsearched abstracts from pulmonary symposia and the North American Cystic Fibrosis Conferences. Date of most recent register search: 10 September 2020. We searched online trials registries; date of most recent searches: 21 March 2020.. Randomized controlled trials comparing all methods of pharmacological diabetes therapy in people with diagnosed CFRD.. Two authors independently extracted data and assessed the risk of bias in the included studies. Authors also used GRADE to assess the quality of the evidence.. The searches identified 29 trials (45 references). Four included trials provide results: one short-term single-center cross-over trial (seven adults) comparing insulin with oral repaglinide and no medication in adults with CFRD and normal fasting glucose; one long-term multicenter trial (61 adults with CFRD) comparing insulin with oral repaglinide and placebo; one long-term multicenter trial (67 adults) comparing insulin with oral repaglinide; and one 12-week single-center cross-over trial (20 adults) comparing the long-acting insulin glargine to short-term neutral protamine Hagedorn insulin. Two ongoing trials of newly approved incretin mimics have been noted for possible future inclusion. Downgrading of the quality of the evidence was mainly due to risks of bias across all domains, but particularly due to concerns surrounding allocation concealment and selective reporting. There were also some concerns due to imprecision from small sample sizes and low event rates. Finally, there may be some bias due to the amounts of insulin and repaglinide given not being comparable. Data from one trial comparing insulin to placebo (39 participants) did not show any difference between groups for the primary outcomes of blood glucose levels (very low-quality evidence), lung function (low-quality evidence) or nutritional status (low-quality evidence). Similarly, no differences between groups were seen for the secondary outcomes of number of hypoglycemic episodes (low-quality evidence), secondary infection complications or quality of life (QoL). These results were mirrored in the narrative reports for the second trial in this comparison (seven participants). Data from the one-year trial comparing repaglinide to placebo (38 participants), showed no differences between groups for the primary outcomes of blood glucose levels (very low-quality evidence), lung function (low-quality evidence) and nutritional status (low-quality evidence). Also, no differences were seen between groups for the secondary outcomes of number of hypoglycemic episodes (low-quality evidence), secondary infection complications or QoL. These findings were mirrored in the narrative reports for the second trial (n = 7) in this comparison. Three trials compared insulin to repaglinide (119 participants). Data from one trial (n = 67) showed no difference in blood glucose levels at either 12 months (high-quality evidence) or 24 months; narrative reports from one trial (45 participants) reported no difference. This review has not found any conclusive evidence that any agent has a distinct advantage over another in controlling hyperglycemia or the clinical outcomes associated with CFRD. Given the treatment burden already experienced by people with cystic fibrosis, oral therapy may be a viable treatment option. While some cystic fibrosis centers use oral medications to help control diabetes, the Cystic Fibrosis Foundation (USA) clinical practice guidelines support the use of insulin therapy and this remains the most widely-used treatment method. Randomized controlled trials specifically related to controlling diabetes and its impact on the course of pulmonary disease process in cystic fibrosis continue to be a high priority. Specifically, investigators should evaluate adherence to different therapies and also whether there is benefit in using additional hypoglycemic agents as well as the newly approved incretin mimics. Agents that potentiate insulin action, especially agents with additional anti-inflammatory potential should also be further investigated as adjuvant therapy to insulin.

Topics: Administration, Oral; Bias; Blood Glucose; Carbamates; Cystic Fibrosis; Diabetes Mellitus; Fasting; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Glargine; Insulin, Isophane; Piperidines; Randomized Controlled Trials as Topic

The term prediabetes is used to describe a population with an elevated risk of developing type 2 diabetes mellitus (T2DM). With projections of an increase in the incidence of T2DM, prevention or delay of the disease and its complications is paramount. It is currently unknown whether pioglitazone is beneficial in the treatment of people with increased risk of developing T2DM.. To assess the effects of pioglitazone for prevention or delay of T2DM and its associated complications in people at risk of developing T2DM.. We searched CENTRAL, MEDLINE, Chinese databases, ICTRP Search Portal and ClinicalTrials.gov. We did not apply any language restrictions. Further, we investigated the reference lists of all included studies and reviews. We tried to contact all study authors. The date of the last search of databases was November 2019 (March 2020 for Chinese databases).. We included randomised controlled trials (RCTs) with a minimum duration of 24 weeks, and participants diagnosed with intermediate hyperglycaemia with no concomitant diseases, comparing pioglitazone as monotherapy or part of dual therapy with other glucose-lowering drugs, behaviour-changing interventions, placebo or no intervention.. Two review authors independently screened abstracts, read full-text articles and records, assessed risk of bias and extracted data. We performed meta-analyses with a random-effects model and calculated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, with 95% confidence intervals (CIs) for effect estimates. We evaluated the certainty of the evidence with the GRADE.. We included 27 studies with a total of 4186 randomised participants. The size of individual studies ranged between 43 and 605 participants and the duration varied between 6 and 36 months. We judged none of the included studies as having low risk of bias across all 'Risk of bias' domains. Most studies identified people at increased risk of T2DM by impaired fasting glucose or impaired glucose tolerance (IGT), or both. Our main outcome measures were all-cause mortality, incidence of T2DM, serious adverse events (SAEs), cardiovascular mortality, nonfatal myocardial infarction or stroke (NMI/S), health-related quality of life (QoL) and socioeconomic effects. The following comparisons mostly reported only a fraction of our main outcome set. Three studies compared pioglitazone with metformin. They did not report all-cause and cardiovascular mortality, NMI/S, QoL or socioeconomic effects. Incidence of T2DM was 9/168 participants in the pioglitazone groups versus 9/163 participants in the metformin groups (RR 0.98, 95% CI 0.40 to 2.38; P = 0.96; 3 studies, 331 participants; low-certainty evidence). No SAEs were reported in two studies (201 participants; low-certainty evidence). One study compared pioglitazone with acarbose. Incidence of T2DM was 1/50 participants in the pioglitazone group versus 2/46 participants in the acarbose group (very low-certainty evidence). No participant experienced a SAE (very low-certainty evidence).One study compared pioglitazone with repaglinide. Incidence of T2DM was 2/48 participants in the pioglitazone group versus 1/48 participants in the repaglinide group (low-certainty evidence). No participant experienced a SAE (low-certainty evidence). One study compared pioglitazone with a personalised diet and exercise consultation. All-cause and cardiovascular mortality, NMI/S, QoL or socioeconomic effects were not reported. Incidence of T2DM was 2/48 participants in the pioglitazone group versus 5/48 participants in the diet and exercise consultation group (low-certainty evidence). No participant experienced a SAE (low-certainty evidence). Six studies compared pioglitazone with placebo. No study reported on QoL or socioeconomic effects. All-cause mortality was 5/577 participants the in the pioglitazone groups versus 2/579 participants in the placebo groups (Peto odds ratio 2.38, 95% CI 0.54 to 10.50; P = 0.25; 4 studies, 1156 participants; very low-certainty evidence). Incidence of T2DM was 80/700 participants in the pioglitazone groups ve. Pioglitazone reduced or delayed the development of T2DM in people at increased risk of T2DM compared with placebo (low-certainty evidence) and compared with no intervention (moderate-certainty evidence). It is unclear whether the effect of pioglitazone is sustained once discontinued. Pioglitazone compared with metformin neither showed advantage nor disadvantage regarding the development of T2DM in people at increased risk (low-certainty evidence). The data and reporting of all-cause mortality, SAEs, micro- and macrovascular complications were generally sparse. None of the included studies reported on QoL or socioeconomic effects.

Topics: Acarbose; Bias; Carbamates; Cardiovascular Diseases; Confidence Intervals; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Metformin; Pioglitazone; Piperidines; Placebos; Randomized Controlled Trials as Topic; Risk

The purpose of this systematic review and meta-analysis was to summarize the potential impact of CYP2C8 and SLCO1B1 genetic polymorphisms on repaglinide pharmacokinetics.. A systematic search was conducted using electronic databases. Eligible studies reported data from pharmacokinetic evaluations of repaglinide in healthy adults according to different categories of CYP2C8 and SLCO1B1 genetic polymorphisms.. Six studies including a total of 191 participants met the inclusion criteria. We noted that CYP2C8 *1/*3 carriers exhibited lower AUC(0-∞) (SMD: -0.77; 95%CI: -1.23 to -0.30; P=0.001) and Cmax (SMD: -0.94; 95%CI: - 1.41 to -0.47; P<0.001) than CYP2C8 *1/*1 carriers. There were no significant differences in AUC(0-∞), Cmax, t1/2 and mean change in blood glucose concentration between *1/*4 and *1/*1 carriers. Further, *3/*3 carriers had lower Cmax (SMD: -1.42; 95%CI: -2.66 to -0.17; P=0.026) than *1/*1 carriers. Additionally, *3/*3 carriers had lower Cmax than *1/*3 carriers (SMD: -1.20; 95%CI: -2.40 to -0.00; P=0.050). Finally, we noted that repaglinide pharmacokinetics did not differ by SLCO1B1 genotype.. The current systematic review and meta-analysis indicated that the genotype of CYP2C8, but not SLCO1B1, may affect repaglinide pharmacokinetics. However, because of the comparatively insufficient number of published studies included, our conclusions require support from additional studies.

Topics: Carbamates; Cytochrome P-450 CYP2C8; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Piperidines; Polymorphism, Genetic

Prevention of cognitive impairment and dementia is an important public health goal. Epidemiological evidence shows a relationship between cognitive impairment and Type 2 diabetes mellitus. The risk of dementia increases with duration of disease. This updated systematic review investigated the effect on cognitive function of the type of treatment and level of metabolic control in people with Type 2 diabetes.. To assess the effects of different strategies for managing Type 2 diabetes mellitus on cognitive function and the incidence of dementia.. We searched ALOIS (the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG)), the Cochrane Library, MEDLINE, Embase, PsycINFO, CINAHL and LILACS on 15 October 2016. ALOIS contains records from all major health care databases, (CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, LILACS), as well as from many trials' registers and grey literature sources.. We included randomised controlled trials (RCTs) which compared two or more different treatments for Type 2 diabetes mellitus and in which cognitive function was measured at baseline and after treatment.. Two review authors independently extracted data and assessed the quality of the included RCTs. We pooled data for comparable trials and estimated the effects of treatment by using risk ratios (RRs) and mean differences (MDs), according to the nature of the outcome. We assessed the quality of the evidence using GRADE methods.. We identified seven eligible studies but only four provided data we could include in efficacy analyses. Two of these studies compared intensive versus standard glycaemic control and two compared different pharmacological treatments. All studies were at unclear risk of bias in at least two domains and one large study was at high risk of performance and detection bias.(a) Two studies with 13,934 participants at high cardiovascular risk provided efficacy data on intensive versus standard glycaemic control. A third study with 1791 participants provided additional data on hypoglycaemic episodes and mortality. There is probably no difference between treatment groups in the number of participants who decline by at least 3 points on the Mini-Mental State Examination (MMSE) over five years (RR 0.98, 95% CI 0.88 to 1.08; 1 study; n = 11,140; moderate-quality evidence); and there may also be little or no difference in the incidence of dementia (RR 1.27, 95% CI 0.87 to 1.85; 1 study; n = 11,140; low-quality evidence). From another study, there was probably little or no difference in MMSE score after 40 months (MD -0.01, 95% CI -0.18 to 0.16; 1 study; n = 2794; moderate quality evidence). Participants exposed to the intensive glycaemic control strategy probably experience more episodes of severe hypoglycaemia than those who have standard treatment (RR 2.18, 95% CI 1.52 to 3.14; 2 studies; n = 12,827; moderate-quality evidence). The evidence from these trials suggests that the intensity of glycaemic control may have little or no effect on all-cause mortality (RR 0.99, 95% CI 0.87 to 1.13; 3 studies; n = 15,888; low-quality evidence).(b) One study with 156 participants compared glibenclamide (glyburide) with repaglinide. There may be a small advantage of glibenclamide on global cognitive function measured with the MMSE after 12 months (MD -0.90, 95% CI -1.68 to -0.12; low-quality evidence). No data were reported on the incidence of dementia, hypoglycaemic events or all-cause mortality.(c) One study with 145 participants compared rosiglitazone plus metformin to glibenclamide (glyburide) plus metformin over 24 weeks. It reported only on cognitive subdomains and not on global cognitive function, incidence of MCI or dementia, hypoglycaemic events or all causes of mortality.. We found no good evidence that any specific treatment or treatment strategy for Type 2 diabetes can prevent or delay cognitive impairment. The best available evidence related to the comparison of intensive with standard glycaemic control strategies. Here there was moderate-quality evidence that the strategies do not differ in their effect on global cognitive functioning over 40 to 60 months.

Topics: Carbamates; Cause of Death; Cognition Disorders; Diabetes Mellitus, Type 2; Glyburide; Humans; Hypoglycemic Agents; Memory Disorders; Metformin; Piperidines; Randomized Controlled Trials as Topic; Rosiglitazone; Thiazolidinediones

The Cystic Fibrosis Foundation recommends both short-term and long-acting insulin therapy when cystic fibrosis-related diabetes has been diagnosed. Diagnosis is based on: an elevated fasting blood glucose level greater than 6.94 mmol/liter (125 mg/deciliter); or oral glucose tolerance tests greater than 11.11 mmol/liter (200 mg/deciliter) at two hours; or symptomatic diabetes for random glucose levels greater than 11.11 mmol/liter (200 mg/deciliter); or glycated hemoglobin levels of at least 6.5%.. To establish the effectiveness of insulin and oral agents for managing diabetes in people with cystic fibrosis in relation to blood sugar levels, lung function and weight management.. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also handsearched abstracts from pulmonary symposia and the North American Cystic Fibrosis Conferences.Date of the most recent search of the Group's Cystic Fibrosis Trials Register: 18 February 2016.. Randomized controlled trials comparing all methods of diabetes therapy in people with diagnosed cystic fibrosis-related diabetes.. Two authors independently extracted data and assessed the risk of bias in the included studies.. The searches identified 22 trials (34 references). Four trials (200 participants) are included: one short-term single-center trial (n = 7) comparing insulin with oral repaglinide and no medication in people with cystic fibrosis-related diabetes and normal fasting glucose; one long-term multicenter trial (n = 100, 74 of whom had cystic fibrosis-related diabetes) comparing insulin with oral repaglinide and placebo; one long-term multicenter trial (n = 73) comparing insulin with oral repaglinide; and one 12-week single-center trial (n = 20) comparing the long-acting insulin glargine to short-term neutral protamine Hagedorn insulin.Two trials with data for the comparison of insulin to placebo did not report any significant differences between groups for the primary outcomes of blood glucose levels, lung function and nutritional status. This was also true for the single trial with data for the comparison of repaglinide to placebo. Two trials (one lasting one year and one lasting two years) contributed data for the comparison of insulin versus repaglinide. There were no significant differences for the primary outcomes at any time point, except at one year (in the two-year trial) when the insulin group had significant improvement in z score for body mass index compared to the repaglinide group. The single trial comparing glargine to neutral protamine Hagedorn insulin also did not report any significant differences in the review's primary outcomes. A few cases of hypoglycemia were seen in three out of the four trials (none in the longest trial), but these events resolved without further treatment.There was an unclear risk of bias from randomization and allocation concealment in two of the four included trials as the authors did not report any details; in the remaining two studies details for randomization led to a low risk of bias, but only one had sufficient details on allocation concealment to allow a low risk judgement, the second was unclear. There was a high risk from blinding for all trials (except for the comparison of oral repaglinide versus placebo) due to the nature of the interventions. Complete data for all outcomes were not available from any trial leading to a high risk of reporting bias. The amounts of insulin and repaglinide administered were not comparable and this may lead to bias in the results. None of the included trials were powered to show a significant improvement in lung function.. This review has not found any significant conclusive evidence that long-acting insulins, short-acting insulins or oral hypoglycemic agents have a distinct advantage over one another in controlling hyperglycemia or clinical outcomes associated with cystic fibrosis-related diabetes. While some cystic fibrosis centers use oral medications to help control diabetes, the Cystic Fibrosis Foundation (USA) clinical practice guidelines support the use of insulin therapy and this remains the most widely-used treatment method. Randomized controlled trials specifically related to controlling diabetes with this impact on the course of pulmonary disease process in cystic fibrosis continue to be a high priority.There is no demonstrated advantage yet established for using oral hypoglycemic agents over insulin, and further trials need to be evaluated to establish whether there is clear benefit for using hypoglycemic agents. Agents that potentiate insulin action, especially agents with additional anti-inflammatory potential should be further investigated to see if there may be a clinical advantage to adding these medications to insulin as adjuvant therapy.

Topics: Administration, Oral; Carbamates; Cystic Fibrosis; Diabetes Mellitus; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Glargine; Insulin, Isophane; Piperidines; Randomized Controlled Trials as Topic

Glinides, including repaglinide, nateglinide and mitiglinide, are a type of fasting insulin secretagogue that could help to mimic early-phase insulin release, thus providing improved control of the postprandial glucose levels. Glinides stimulate insulin secretion by inhibiting ATP-sensitive potassium channels in the pancreatic β-cell membrane. Although glinides have been widely used clinically and display excellent safety and efficacy, the response to glinides varies among individuals, which is partially due to genetic factors involved in drug absorption, distribution, metabolism and targeting. Several pharmacogenomic studies have demonstrated that variants of genes involved in the pharmacokinetics or pharmacodynamics of glinides are associated with the drug response. Polymorphisms of genes involved in drug metabolism, such as CYP2C9, CYP2C8 and SLCO1B1, may influence the efficacy of glinides and the incidence of adverse effects. In addition, Type 2 diabetes mellitus susceptibility genes, such as KCNQ1, PAX4 and BETA2, also influence the efficacy of glinides. In this article, we review and discuss current pharmacogenomics researches on glinides, and hopefully provide useful data and proof for clinical application.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Inactivation, Metabolic; Insulin; Insulin Secretion; Insulin-Secreting Cells; Isoindoles; KATP Channels; Nateglinide; Pharmacogenetics; Phenylalanine; Piperidines

Type 2 diabetes mellitus (T2DM) is characterized by multiple pathophysiologic abnormalities. With time, multiple glucose-lowering medications are commonly required to reduce and maintain plasma glucose concentrations within the normal range. Type 2 diabetes mellitus individuals also are at a very high risk for microvascular complications and the incidence of heart attack and stroke is increased two- to three-fold compared with non-diabetic individuals. Therefore, when selecting medications to normalize glucose levels in T2DM patients, it is important that the agent not aggravate, and ideally even improve, cardiovascular risk factors (CVRFs) and reduce cardiovascular morbidity and mortality. In this review, we examine the effect of oral (metformin, sulfonylureas, meglitinides, thiazolidinediones, DPP4 inhibitors, SGLT2 inhibitors, and α-glucosidase inhibitors) and injectable (glucagon-like peptide-1 receptor agonists and insulin) glucose-lowering drugs on established CVRFs and long-term studies of cardiovascular outcomes. Firm evidence that in T2DM cardiovascular disease can be reversed or prevented by improving glycaemic control is still incomplete and must await large, long-term clinical trials in patients at low risk using modern treatment strategies, i.e., drug combinations designed to maximize HbA1c reduction while minimizing hypoglycaemia and excessive weight gain.

Topics: Carbamates; Clinical Trials as Topic; Coronary Artery Disease; Cyclohexanes; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Dipeptidyl-Peptidase IV Inhibitors; Glucagon-Like Peptide-1 Receptor; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Insulin; Metformin; Nateglinide; Phenylalanine; Piperidines; Sodium-Glucose Transport Proteins; Sulfonylurea Compounds; Thiazolidinediones; Treatment Outcome

We performed a systematic review to identify which genetic variants predict response to diabetes medications.. We performed a search of electronic databases (PubMed, EMBASE, and Cochrane Database) and a manual search to identify original, longitudinal studies of the effect of diabetes medications on incident diabetes, HbA1c, fasting glucose, and postprandial glucose in prediabetes or type 2 diabetes by genetic variation. Two investigators reviewed titles, abstracts, and articles independently. Two investigators abstracted data sequentially and evaluated study quality independently. Quality evaluations were based on the Strengthening the Reporting of Genetic Association Studies guidelines and Human Genome Epidemiology Network guidance.. Of 7,279 citations, we included 34 articles (N = 10,407) evaluating metformin (n = 14), sulfonylureas (n = 4), repaglinide (n = 8), pioglitazone (n = 3), rosiglitazone (n = 4), and acarbose (n = 4). Studies were not standalone randomized controlled trials, and most evaluated patients with diabetes. Significant medication-gene interactions for glycemic outcomes included 1) metformin and the SLC22A1, SLC22A2, SLC47A1, PRKAB2, PRKAA2, PRKAA1, and STK11 loci; 2) sulfonylureas and the CYP2C9 and TCF7L2 loci; 3) repaglinide and the KCNJ11, SLC30A8, NEUROD1/BETA2, UCP2, and PAX4 loci; 4) pioglitazone and the PPARG2 and PTPRD loci; 5) rosiglitazone and the KCNQ1 and RBP4 loci; and 5) acarbose and the PPARA, HNF4A, LIPC, and PPARGC1A loci. Data were insufficient for meta-analysis.. We found evidence of pharmacogenetic interactions for metformin, sulfonylureas, repaglinide, thiazolidinediones, and acarbose consistent with their pharmacokinetics and pharmacodynamics. While high-quality controlled studies with prespecified analyses are still lacking, our results bring the promise of personalized medicine in diabetes one step closer to fruition.

Topics: Acarbose; Biomarkers, Pharmacological; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Metformin; Pharmacogenetics; Pioglitazone; Piperidines; Polymorphism, Genetic; Prediabetic State; Rosiglitazone; Sulfonylurea Compounds; Thiazolidinediones

We conducted a meta-analysis to compare the efficacy and safety of repaglinide plus metformin with metformin alone on type 2 diabetes. Twenty-two studies were included in this meta-analysis. Results showed combination therapy was safe and could gain better outcomes in glycemic control. Well-designed studies are required to confirm this conclusion.

Topics: Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Metformin; Piperidines

Treating patients with diabetes is one of the most challenging and important activities a physician (primary care physician or specialist) can undertake. A key to successful therapy for type 2 diabetes is the insight that this condition is progressive and that the need for additional agents over time is normative. The ability to individualize therapy by patient and medication characteristics comes from experience and knowledge of pertinent clinical studies. However, guidelines from expert bodies such as the American Diabetes Association/European Association for the Study of Diabetes and American Association of Clinical Endocrinologists/American College of Endocrinology can help clinicians of all levels of expertise to approach therapy choices more rationally. There is unity across these guidelines about the role and benefits of metformin as first-line pharmacological treatment, probability of good efficacy, low risk of hypoglycemia, modest weight loss, and overall long-term data. Unfortunately, this unity does not extend to recommendations for subsequent pharmacological agents and their use in combination to intensify treatment when insulin is not (yet) appropriate. Across both statements, some drug classes seem more prominent, and looking at their benefit-risk profile, it is clear why this is the case. The most profound recent change in diabetes therapy has been the introduction of incretin therapies. Incretin therapies minimize 2 important adverse effects seen with many other therapies: hypoglycemia and weight gain. These agents have increased the range of options available for early intensification of treatment of type 2 diabetes. In combination with more established therapies, there are more opportunities than ever to accommodate patient preferences while improving glycemic control and harnessing extraglycemic benefits of a second (or third) agent.

Topics: Algorithms; Carbamates; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Drug Therapy, Combination; Exenatide; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Humans; Hypoglycemic Agents; Incretins; Insulin; Liraglutide; Metformin; Peptides; Piperidines; Practice Guidelines as Topic; Receptors, Glucagon; Sulfonylurea Compounds; Thiazolidinediones; Venoms

Insulin secretagogues promote insulin release by binding to sulfonylurea receptors on pancreatic β-cells (SUR1). However, these drugs also bind to receptor isoforms on cardiac myocytes (SUR2A) and vascular smooth muscle (SUR2B). Binding to SUR2A/SUR2B may inhibit ischaemic preconditioning, an endogenous protective mechanism enabling cardiac tissue to survive periods of ischaemia. This study was designed to identify insulin secretagogues that selectively bind to SUR1 when given at therapeutic doses.. Using accepted systematic review methods, three electronic databases were searched from inception to 13 June 2011. Original studies measuring the half-maximal inhibitory concentration (IC(50)) for an insulin secretagogue on K(ATP) channels using standard electrophysiological techniques were included. Steady-state concentrations (C(SS)) were estimated from the usual oral dose and clearance values for each drug.. Data were extracted from 27 studies meeting all inclusion criteria. IC(50) values for SUR1 were below those for SUR2A/SUR2B for all insulin secretagogues and addition of C(SS) values identified three distinct patterns. The C(SS) for gliclazide, glipizide, mitiglinide and nateglinide lie between IC(50) values for SUR1 and SUR2A/SUR2B, suggesting that these drugs bind selectively to pancreatic receptors. The C(SS) for glimepiride and glyburide (glibenclamide) was above IC(50) values for all three isoforms, suggesting these drugs are non-selective. Tolbutamide and repaglinide may have partial pancreatic receptor selectivity because IC(50) values for SUR1 and SUR2A/SUR2B overlapped somewhat, with the C(SS) in the midst of these values.. Insulin secretagogues display different tissue selectivity characteristics at therapeutic doses. This may translate into different levels of cardiovascular risk.

Topics: Animals; ATP-Binding Cassette Transporters; Carbamates; Cardiovascular Diseases; Cricetinae; Cyclohexanes; Diabetes Mellitus, Type 2; Gliclazide; Glipizide; Glyburide; Humans; Hypoglycemic Agents; Ischemic Preconditioning, Myocardial; Isoindoles; Mice; Muscle, Smooth, Vascular; Myocytes, Cardiac; Nateglinide; Phenylalanine; Piperidines; Potassium Channels, Inwardly Rectifying; Rats; Receptors, Drug; Risk Factors; Sulfonylurea Compounds; Sulfonylurea Receptors; Tolbutamide

Oral repaglinide (GlucoNorm®; NovoNorm®; Prandin®; Surepost®) is a rapid-acting insulin secretagogue that lowers postprandial glucose (PPG) excursions by targeting early-phase insulin release, with reductions in PPG considered to be important in reducing long-term cardiovascular complications of diabetes mellitus. Repaglinide, a carbamoylbenzoic acid derivative, is chemically related to the meglitinide class of insulin secretagogues, but unrelated to the sulfonylurea insulin secretagogues. Meglitinides, including repaglinide, have a distinct binding site at the β-cell membrane, which differs from that of sulfonylureas, and corresponds to greater insulinotropic effects with repaglinide than with glibenclamide and/or glimepiride and a more rapid onset of action in in vitro and in vivo studies. This article reviews the clinical efficacy and tolerability of oral repaglinide in the treatment of patients with type 2 diabetes and provides an overview of its pharmacological properties. In well designed clinical trials of up to 52 weeks' duration and in the clinical practice setting, recommended dosages of repaglinide (0.5-4 mg three times daily up to 30 minutes prior to a meal) provided effective glycaemic control and were generally well tolerated in treatment-naive or -experienced adult patients with type 2 diabetes, including elderly patients and those with renal impairment. Furthermore, as monotherapy or in combination with other oral antihyperglycaemic drugs, repaglinide was at least as effective as other oral antihyperglycaemic drugs at improving or maintaining glycaemic control, with a tolerability profile that was generally similar to that of sulfonylurea drugs and nateglinide. Thus, repaglinide remains an effective option for the management of patients with type 2 diabetes.

Topics: Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Piperidines; Randomized Controlled Trials as Topic

Topics: Aged; Azepines; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Interactions; Humans; Hypnotics and Sedatives; Hypoglycemia; Hypoglycemic Agents; Male; Piperidines; Sleep Wake Disorders

The cytochrome P4502C enzymes account for the metabolism of approximately 20% of therapeutic drugs including certain oral antidiabetic drugs (OADs).. This review focuses on the effect of CYP2C enzymes on metabolism of sulphonylureas (SUs), meglitinides, and thiazolidinediones (TZDs) discussing their impact on pharmacokinetics, drug interactions and toxicological profiles. Pharmacogenetic aspects reflecting individual gene variants and variable drug effects are also considered.. Genetic polymorphisms of CYP2C9 enzymes (*2/*2, *2/*3, *3/*3) influence the glycaemic response to SUs and impair their substrate metabolism. Restricted data from small-sized studies with heterogenous definitions of hypoglycaemia revealed no clear association between CYP2C9 genotypes and the risk of hypoglycaemia. Functional polymorphisms of CYP2C8- and CYP2C9 drug metabolizing genes affect markedly pharmacokinetics of meglitinides. Compared to wild-type carriers, patients treated with TZDs and carrying the common CYP2C8*3 and *4 variants showed a reduced glycaemic control. The strong CYP2C8 and OATP1B1 inhibitor gemfibrozil increases substantially the plasma concentrations of repaglinide and TZDs. Numerous metabolic drug interactions exist between SUs and commonly prescribed drugs, especially anti-infectives. The complex pharmacokinetic and pharmacogenetic properties and the unfavourable short and long term risk profile of glibenclamide and glimepiride raise the question whether their use can be justified any longer.

Topics: Administration, Oral; Benzamides; Blood Glucose; Carbamates; Cytochrome P-450 Enzyme System; Drug Interactions; Gemfibrozil; Humans; Hypoglycemic Agents; Inactivation, Metabolic; Pharmacogenetics; Piperidines; Polymorphism, Single Nucleotide; Sulfonylurea Compounds; Thiazolidinediones

Various drug transporters are selectively expressed in single or multiple tissues, such as the intestine, liver and kidney, where these transporters play various roles in drug absorption, distribution and excretion. Genetic polymorphisms in drug transporters as well as drug-metabolizing enzymes are associated with interindividual differences in drug disposition, efficacy and toxicity. Organic anion transporting polypeptide 1B1 (OATP1B1, gene SLCO1B1) is expressed on the basolateral membrane of hepatocytes and can facilitate hepatic uptake of certain clinically relevant drugs such as statins except for fluvastatin, angiotensin converting enzyme inhibitors, angiotensin II receptor antagonists, antidiabetic drug (repaglinide) and anticancer drugs (SN-38 and methotrexate). Some single nucleotide polymorphisms or haplotypes of the SLCO1B1 gene have been identified and demonstrated to have functional significance for transporter activity. For examples, the SLCO1B1*15 haplotype (or 521T>C genotype) results in decreased uptake activity of SN-38 from systemic circulation, leading to increased plasma concentration of SN-38 and an enhanced risk of neutropenia. This review focuses on the impact of genetic polymorphisms of the SLCO1B1 gene on transport activity, and implications for the clinical efficacy and toxicity of clinically useful drugs.

Topics: Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Antineoplastic Agents, Phytogenic; Camptothecin; Carbamates; Haplotypes; Hepatocytes; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoglycemic Agents; Irinotecan; Liver; Liver-Specific Organic Anion Transporter 1; Organic Anion Transporters; Pharmacogenetics; Piperidines; Polymorphism, Genetic

Repaglinide solid lipid nanoparticles (RG-SLN) were fabricated using stearic acid as lipid. Pluronic F68 (PLF68) and soya lecithin were used as a stabilizer. SLNs were prepared by modified solvent injection and ultrasonication methods. SLNs prepared with modified solvent injection method have larger particle size (360+/-2.5nm) than prepared with ultrasonication method (281+/-5.3nm). The zeta potential of the prepared formulations by these two methods varied from - 23.10 +/-1.23 to -26.01 +/-0.89 mV. The maximum entrapment efficiency (62.14 +/-1.29%) was obtained in modified solvent injection method. The total drug content was nearly same (98%) in both the methods. In vitro release studies were performed in phosphate buffer (pH 6.8) with 0.5% sodium lauryl sulphate (SLS) using dialysis bag diffusion technique. The cumulative drug release was 30% and 50% within 2 hrs in modified solvent injection and ultrasonication method, respectively. This indicates that RG-SLN prepared from modified injection method released the drug more slowly than SLNs prepared with ultrasonication method. Differential scanning calorimetry indicates that repaglinide (RG) entrapped in the solid lipid nanoparticles (SLN) exist in an amorphous or molecular state. Repaglinide loaded solid lipid nanoparticles prepared with both methods were of spherical shape as observed by transmission electron microscopy (TEM). These results suggest that modified solvent injection method is more suitable for preparation of repaglinide SLNs using stearic acid.

Topics: Biological Availability; Calorimetry, Differential Scanning; Carbamates; Drug Carriers; Hypoglycemic Agents; Lipids; Microscopy, Electron, Transmission; Nanostructures; Particle Size; Piperidines

In vitro investigation of pharmacokinetic drug-drug interactions (DDIs) has officially been part of the regulatory pathway for new drugs in the USA since the publication of an FDA guidance on the subject in 1997. The field has continued to evolve, driven by preclinical and clinical experience, improved understanding of the molecular basis of DDIs, technological advances, and a continuous dialogue between the FDA and pharmaceutical industry scientists. Some striking DDIs involve multiple molecular species and targets; their mechanisms and magnitude would have been difficult or impossible to predict with available in vitro tools. This article focuses on one such example.

Topics: Carbamates; Drug Approval; Drug Evaluation, Preclinical; Drug Industry; Drug Interactions; Drug Therapy, Combination; Gemfibrozil; Humans; Itraconazole; Models, Biological; Piperidines

Organic anion-transporting polypeptide 1B1 (OATP1B1; gene: SLCO1B1) is an influx transporter expressed on the sinusoidal membrane of human hepatocytes, where it mediates the uptake of its substrates from blood into liver. In vitro, the SLCO1B1 c.521T>C (p.Val174Ala) single-nucleotide polymorphism (SNP) has been associated with reduced and the c.388A>G (p.Asn130Asp) SNP with both enhanced and reduced transport activity of OATP1B1. In vivo in humans, the c.521C allele (present in SLCO1B1*5 and *15 haplotypes) is associated with decreased hepatic uptake and increased plasma concentrations of several OATP1B1 substrates. The SLCO1B1*1B (c.388G-c.521T) haplotype is associated with enhanced hepatic uptake and decreased plasma concentrations of some OATP1B1 substrates. The SLCO1B1 c.521CC genotype has been associated with an about 60-190% increased, and the SLCO1B1*1B/*1B genotype with an about 30% decreased area under the plasma concentration-time curve of repaglinide. Moreover, SLCO1B1 polymorphism can affect the extent of interaction between OATP1B1 inhibitors and repaglinide. Accordingly, SLCO1B1 genotyping may help in choosing the optimal starting dose of repaglinide. In Chinese individuals, the SLCO1B1 c.521C allele has been associated with increased plasma concentrations of nateglinide, but the association could not be replicated in Caucasians. SLCO1B1 genotype has had no effect on the pharmacokinetics of rosiglitazone, pioglitazone or their metabolites. The hepatic uptake of metformin is mediated by organic cation transporters 1 and 3, and the liver is not important for the elimination or action of the dipeptidylpeptidase 4 inhibitors sitagliptin, vildagliptin and saxagliptin. Therefore, SLCO1B1 polymorphism unlikely affects the response to these antidiabetics. Possible effects of SLCO1B1 polymorphism on sulfonylureas remain to be investigated.

Topics: Administration, Oral; Alleles; Carbamates; Cyclohexanes; Genotype; Haplotypes; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Nateglinide; Organic Anion Transporters; Phenylalanine; Pioglitazone; Piperidines; Polymorphism, Genetic; Rosiglitazone; Thiazolidinediones

The purpose of this study is to evaluate efficacy and safety of nateglinide tablet administration in comparison with those of repaglinide tablet as control on treating type 2 diabetes mellitus in China. Pooled-analysis with analysis of covariance (ANCOVA) method was applied to assess the efficacy and safety based on original data collected from four independent randomized clinical trials with similar research protocols. However meta-analysis was applied based on the outcomes of the four studies. The results by meta-analysis were comparable to those obtained by pooled-analysis. The means of HbA(1c), and fasting blood glucose in both the nateglinide and repaglinide groups were reduced significantly after 12 weeks duration but no statistical differences in reduction between the two groups. The adverse reaction rates were 9.89 and 6.51% in the nateglinide and repaglinide groups respectively, with the rate difference showing no statistical significance, and the Odds Ratio of adverse reaction rate (95% confidence interval) was 1.59 (0.99, 2.55). Both nateglinide and repaglinide administration have similarly significant effects on reducing HbA(1c) and FBG. However, the adverse reaction rate in the nateglinide group is higher than that in the latter using repaglinide but no statistical significance difference as revealed in the four clinical trials detailed below.

Topics: Carbamates; China; Cyclohexanes; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines

Topics: alpha-Galactosidase; Biguanides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Combinations; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Insulin; Nateglinide; Phenylalanine; Piperidines; Pyrazines; Sitagliptin Phosphate; Sulfonylurea Compounds; Thiazolidinediones; Triazoles

Type 2 diabetes is characterized by decreases in insulin secretion and insulin sensitivity. Several classes of oral antidiabetic medications are currently approved for the treatment of type 2 diabetes. A stepwise treatment approach from monotherapy to combination therapy is traditionally used; however, the frequency of treatment failure with monotherapy has resulted in a move towards earlier treatment with combination therapies that target the two principal defects in glycaemic control. One such combination regimen is repaglinide (a prandial glucose regulator that increases insulin release) plus metformin (an insulin sensitizer that inhibits hepatic glucose output, increases peripheral glucose uptake and utilization and minimizes weight gain). Findings from several clinical trials have shown that combination therapy with repaglinide plus metformin is well tolerated and results in greater reductions of haemoglobin A(1c) and fasting plasma glucose values compared with either monotherapy. Repaglinide may also provide a more suitable alternative to combination therapy with sulphonylureas and metformin because of its reduced propensity for hypoglycaemia. The combination regimen of repaglinide plus metformin should therefore be considered as a valuable option in the management of patients with type 2 diabetes when monotherapy is no longer adequate.

Topics: Administration, Oral; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Insulin; Metformin; Piperidines; Treatment Outcome; Weight Gain

This review describes the current knowledge on drug-drug and food-drug interactions with repaglinide and nateglinide. These two meglitinide derivatives, commonly called glinides, have been developed for improving insulin secretion of patients with type 2 diabetes mellitus. They are increasingly used either in monotherapy or in combination with other oral antihyperglycaemic agents for the treatment of type 2 diabetes. Compared with sulfonylureas, glinides have been shown to (i) provide a better control of postprandial hyperglycaemia, (ii) overcome some adverse effects, such as hypoglycaemia, and (iii) have a more favourable safety profile, especially in patients with renal failure. The meal-related timing of administration of glinides and the potential influence of food and meal composition on their bioavailability may be important. In addition, some food components (e.g. grapefruit juice) may cause pharmacokinetic interactions. Because glinides are metabolised via cytochrome P450 (CYP) 3A4 isoenzyme, they are indeed exposed to pharmacokinetic interactions. In addition to CYP3A4, repaglinide is metabolised via CYP2C8, while nateglinide metabolism also involves CYP2C9. Furthermore, both compounds and their metabolites may undergo specialised transport/uptake in the intestine, another source of pharmacokinetic interactions. Clinically relevant drug-drug interactions are those that occur when glinides are administered together with other glucose-lowering agents or compounds widely coadministered to diabetic patients (e.g. lipid-lowering agents), with drugs that are known to induce (risk of lower glinide plasma levels and thus of deterioration of glucose control) or inhibit (risk of higher glinide plasma levels leading to hypoglycaemia) CYP isoenzymes concerned in their metabolism, or with drugs that have a narrow efficacy : toxicity ratio. Pharmacokinetic interactions reported in the literature appear to be more frequent and more important with repaglinide than with nateglinide. Rifampicin (rifampin) reduced repaglinide area under the plasma concentration-time curve (AUC) by 32-85% while it reduced nateglinide AUC by almost 25%. Reported increases in AUCs with coadministration of drugs inhibiting CYP isoenzymes never exceeded 80% for repaglinide (except with ciclosporin and with gemfibrozil) and 50% for nateglinide. Ciclosporin more than doubled repaglinide AUC (+144%), a finding that should raise caution when using these two drugs in combination. The most im

Topics: Anti-Bacterial Agents; Area Under Curve; Biological Availability; Biotransformation; Carbamates; Cyclohexanes; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drug Administration Schedule; Drug Interactions; Enzyme Induction; Enzyme Inhibitors; Fasting; Food-Drug Interactions; Humans; Hypoglycemic Agents; Intestinal Absorption; Nateglinide; Phenylalanine; Piperidines; Postprandial Period

In type 2 diabetes mellitus, impairment of insulin secretion is an important component of the disease. Meglitinide analogues are a class of oral hypoglycaemic agents that increase insulin secretion, in particular, during the early phase of insulin release.. The aim of this review was to assess the effects of meglitinide analogues in patients with type 2 diabetes mellitus.. We searched several databases including The Cochrane Library, MEDLINE and EMBASE. We also contacted manufacturers and searched ongoing trials databases, and the American Diabetes Association (ADA) and European Association for the Study of Diabetes (EASD) websites.. We included randomised controlled, parallel or cross-over trials comparing at least 10 weeks of treatment with meglitinide analogues to placebo, head-to-head, metformin or in combination with insulin.. Two authors independently extracted data and assessed trial quality.. Fifteen trials involving 3781 participants were included. No studies reported the effect of meglitinides on mortality or morbidity. In the eleven studies comparing meglitinides to placebo, both repaglinide and nateglinide resulted in a reductions in glycosylated haemoglobin (0.1% to 2.1% reduction in HbA1c for repaglinide; 0.2% to 0.6% for nateglinide). Only two trials compared repaglinide to nateglinide (342 participants), with greater reduction in glycosylated haemoglobin in those receiving repaglinide. Repaglinide (248 participants in three trials) had a similar degree of effect in reducing glycosylated haemoglobin as metformin. Nateglinide had a similar or slightly less marked effect on glycosylated haemoglobin than metformin (one study, 355 participants). Weight gain was generally greater in those treated with meglitinides compared with metformin (up to three kg in three months). Diarrhoea occurred less frequently and hypoglycaemia occurred more frequently but rarely severely enough as to require assistance.. Meglitinides may offer an alternative oral hypoglycaemic agent of similar potency to metformin, and may be indicated where side effects of metformin are intolerable or where metformin is contraindicated. However, there is no evidence available to indicate what effect meglitinides will have on important long-term outcomes, particularly mortality.

Topics: Benzamides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Metformin; Nateglinide; Phenylalanine; Piperidines; Randomized Controlled Trials as Topic

Topics: Acarbose; Carbamates; Chromans; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Pioglitazone; Piperidines; Pyrazoles; Rimonabant; Thiazolidinediones; Troglitazone

Type 2 diabetes mellitus (T2DM) is characterized by hyperglycemia due to a combination of insulin resistance and impaired insulin secretion. The hyperglycemia is associated with an increased risk for micro- and macrovascular complications, and lowering fasting and postprandial hyperglycemia may be protective against these complications. Repaglinide is an insulin secretagogue that lowers blood glucose levels in patients with T2DM. We review the effects of repaglinide in patients with T2DM, its impact on glycemia and its non-glycemic effects, and its effects when used in special situations or patient populations. Results from randomized controlled trials, observational studies, and safety reports involving humans and published in the English-language through 1 May 2007 identified by a search in PubMed/MEDLINE were evaluated. Present knowledge indicates that repaglinide reduces fasting and postprandial hyperglycemia and the level of glycosylated hemoglobin (HbA1c) in patients with T2DM. It is at least as effective in reducing HbA1c and fasting plasma glucose as sulphonylureas, metformin, or the glitazones and in combination therapy with other drugs, repaglinide is as effective as any other combination. Some studies show a better effect of repaglinide on postprandial glycemia than the comparators. Its propensity to induce hypoglycemia is similar to or a little less than that of sulphonylureas. Repaglinide is associated with less weight gain than sulphonylureas and the glitazones. Repaglinide has primarily a role in the treatment of T2DM when metformin cannot be used due to adverse effects, when metformin fails to adequately control blood glucose levels, when there is a need for flexible dosing (i.e. the elderly or during Ramadan fasting), or when there is a specific wish to lower postprandial glucose. Repaglinide may also have an advantage when an oral agent is needed in diabetic patients with renal impairment. Because of its short duration of action, repaglinide should be taken before each meal, usually at least three times a day. Although no study has investigated whether repaglinide lowers total mortality or cardiovascular endpoints, several studies indicate beneficial effects on cardiovascular surrogate endpoints, such as carotid intima-media thickening, markers of inflammation, platelet activation, lipid parameters, endothelial function, adiponectin, and oxidative stress. In conclusion, repaglinide is a compound that can be used in both mono- and combina

Topics: Carbamates; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Drug-Related Side Effects and Adverse Reactions; Humans; Hypoglycemic Agents; Piperidines

Transporters play an important role in the processes of drug absorption, distribution and excretion. In this review, we have focused on the involvement of transporters in drug excretion in the liver and kidney. The rate of transporter-mediated uptake and efflux determines the rate of renal and hepatobiliary elimination. Transporters are thus important as a determinant of the clearance in the body. Even when drugs ultimately undergo metabolism, their elimination rate is sometimes determined by the uptake rate mediated by transporters. Transporters regulate the pharmacological and/or toxicological effect of drugs because they limit their distribution to tissues responsible for their effect and/or toxicity. For example, the liver-specific distribution of some statins via organic anion transporters helps them to produce their high pharmacological effect. On the other hand, as in the case of metformin taken up by organic cation transporter 1, drug distribution to the tissue(s) may enhance its toxicity. As transporter-mediated uptake is a determinant of the drug elimination rate, drug-drug interactions involving the process of transporter-mediated uptake can occur. In this review, we have introduced some examples and described their mechanisms. More recently, some methods to analyze such transporter-mediated transport have been reported. The estimation of the contributions of transporters to the net clearance of a drug makes it possible to predict the net clearance from data involving drug transport in transporter-expressing cells. Double transfected cells, where both uptake and efflux transporters are expressed on the same polarized cells, are also helpful for the analysis of the rate of transporter-mediated transcellular transport.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Bile; Carbamates; Cell Line; Drug Interactions; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoglycemic Agents; Kidney; Liver; Membrane Transport Proteins; Metabolic Clearance Rate; Metformin; Organic Anion Transporters; Organic Cation Transport Proteins; Piperidines; Polymorphism, Genetic; Species Specificity; Tissue Distribution; Transfection

Repaglinide (Prandin), NovoNorm, GlucoNorm, an oral insulin secretagogue, was the first meglitinide analogue to become available for use in patients with type 2 diabetes mellitus. The drug lowers postprandial glucose excursions by targeting early-phase insulin release, an effect thought to be important in reducing long-term cardiovascular complications of diabetes. Repaglinide provided similar overall glycaemic control to that achieved with glibenclamide (glyburide), as assessed by glycosylated haemoglobin (HbA(1c)) and fasting blood glucose levels, and was generally well tolerated in well designed clinical trials. Its rapid onset and relatively short duration of action allow for flexible meal schedules. Two modelled US cost-effectiveness analyses projected lifetime costs and outcomes for a hypothetical cohort of patients with type 2 diabetes. Both analyses projected long-term complications using data on HbA(1c) level changes from short-term clinical trials. Repaglinide plus rosiglitazone was dominant over rosiglitazone in one analysis, and repaglinide plus metformin was dominant over nateglinide plus metformin in the other. A similar Canadian analysis showed a favourable incremental cost-effectiveness ratio (

Topics: Administration, Oral; Carbamates; Clinical Trials as Topic; Cost of Illness; Cost-Benefit Analysis; Diabetes Mellitus, Type 2; Drug Interactions; Economics, Pharmaceutical; Humans; Hypoglycemic Agents; Piperidines; Quality of Life; Randomized Controlled Trials as Topic

[symbol: see text] Nateglinide (Starlix-Novartis) and [symbol: see text] repaglinide (NovoNorm-Novo Nordisk) are two of a new class of orally active antidiabetic drugs, the meglitinides. They have a rapid-onset and short-lasting stimulating effect on insulin secretion. Both are licensed for combination therapy with metformin in patients with type 2 diabetes mellitus who are inadequately controlled by maximally tolerated doses of metformin alone. In addition, repaglinide is licensed for use as monotherapy in patients with type 2 diabetes whose hyperglycaemia can no longer be controlled satisfactorily by diet, weight reduction and exercise. Here we discuss whether repaglinide and nateglinide offer worthwhile advantages in the management of patients with type 2 diabetes.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Double-Blind Method; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines; Randomized Controlled Trials as Topic; Treatment Outcome

Topics: 1-Deoxynojirimycin; Acarbose; Aged; Blood Glucose; Carbamates; Contraindications; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Enzyme Inhibitors; Fasting; Follow-Up Studies; Germany; Glucosamine; Glyburide; Glycated Hemoglobin; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemia; Hypoglycemic Agents; Imino Pyranoses; Insulin; Metformin; Middle Aged; Nateglinide; Obesity; Patient Compliance; Phenylalanine; Pioglitazone; Piperidines; Practice Guidelines as Topic; Risk Factors; Rosiglitazone; Sulfonylurea Compounds; Thiazolidinediones; Time Factors

The expression meglitinide analogs was introduced in 1995 to cover new molecules proposed as non-sulfonylurea insulinotropic agents and displaying structural analogy with meglitinide, such as repaglinide, nateglinide, and mitiglinide. Meglitinide analogs display, as judged by conformation analysis, a U-shaped configuration similar to that of antihyperglycemic sulfonylureas such as glibenclamide (glyburide) and glimepiride. In rat pancreatic islets incubated in the presence of 7.0 mmol/L D-glucose, repaglinide and mitiglinide demonstrate comparable concentration-response relationships for stimulation of insulin release, with a threshold value < 10 nmol/L and a maximal secretory response at about 10 nmol/L. Several findings indicate that meglitinide analogs provoke the closing of adenosine triphosphate-sensitive potassium channels, with subsequent gating of voltage-sensitive calcium channels. The effects of meglitinide analogs upon the binding of [3H]glibenclamide to islet cells membranes reinforces this concept. At variance, however, with other meglitinide analogs, the ionic and secretory response to repaglinide (10 micromol/L) is not rapidly reversible in perifused rat islets. In experiments conducted in vivo in control and diabetic rats, repaglinide provokes a greater and more rapid increase in plasma insulin concentration and an earlier fall in glycemia than glibenclamide or glimepiride. Onset of effect is also more rapid and duration of effect shorter with nateglinide versus glibenclamide. In clinical studies, single or repeated daily administration of repaglinide increased plasma insulin concentration in a dose-dependent manner, with an incremental peak reached about 2 hours after repaglinide intake. Plasma concentrations of repaglinide are about 5.0 microg/L 2-2.5 hours after oral intake of the drug. Despite the slow reversibility of repaglinide action in vitro, this drug offers advantages over glibenclamide in terms of the possible occurrence of hypoglycemia if a meal is missed. In volunteers receiving a single oral dose of nateglinide (120mg) 10 minutes before a standardized 800 Kcal breakfast, the plasma insulin concentration was higher 5, 10, and 20 minutes after meal intake than when they received a single dose of repaglinide (0.5 or 2.0mg) or placebo 10 minutes before breakfast. Peak plasma concentrations of nateglinide were reached within 2 hours in most volunteers. Peak plasma concentrations of mitiglinide were reached 30 minutes after a sing

Topics: Animals; Benzamides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines

Existing oral insulin secretagogues, sulphonylureas, are associated with hyperinsulinaemia, risk of hypoglycaemia and weight gain. Furthermore, they are not able to offer durable glycaemic control in patents with type 2 diabetes and are associated with progressive decline of beta-cell function. New insulin secretagogues offer an exciting opportunity. Repaglinide, the first prandial glucose regulator, now has convincing data that, compared to sulphonylurea use, it has a lower risk of hypoglycaemia. When used in a flexible dosing regime in a large cohort of patients, it is associated with better glycaemic control, a reduction in HbA1c, weight loss and improved quality of life compared to sulphonylureas. Early data shows the possibility of an effective combination with night time isophane insulin with significant falls in HbA1c and lower doses of insulin required. Nateglinide is an amino acid derivative. It again acts directly on the pancreatic beta-cell. Because of its very short duration of action, and the fact that it appears to secrete insulin in a glucose-dependent manner, it appears to secrete insulin in the closest way to that seen in a person without diabetes. Early data, both in monotherapy and in combination with metformin, show that it is an effective agent in terms of lowering HbA1c, has a low risk of hypoglycaemia and potentially less risk of significant weight gain. These characteristics mean that it may be the ideal agent to be used very early in the disease process, or even in subjects with impaired glucose tolerance, in whom early-phase insulin response is already lost. However these concepts, at the present time, are unproven.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Humans; Hyperglycemia; Hyperinsulinism; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Nateglinide; Phenylalanine; Piperidines; Postprandial Period; Sulfonylurea Compounds; United Kingdom

Topics: Adenosine Triphosphate; Animals; ATP-Binding Cassette Transporters; Calcium Channels; Carbamates; Cyclohexanes; Exocytosis; Humans; Hypoglycemic Agents; Indoles; Insulin; Insulin Secretion; Islets of Langerhans; Isoindoles; Nateglinide; Organ Specificity; Phenylalanine; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Receptors, Drug; Sulfonylurea Receptors

Topics: Adenosine Triphosphate; Administration, Oral; Calcium Channels; Carbamates; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Piperidines; Potassium Channels

Peripheral insulin concentrations oscillate because of insulin secretory bursts every 6-10 min, which are the main source of overall insulin release. Regulation of insulin secretion occurs by modification of the mass and to some extent the frequency of the individual insulin secretory bursts. This oscillatory pattern, which is important for insulin action, is observed at the level of the individual beta-cells and in the islets, both in vitro (in the isolated perfused pancreas) and in vivo. It has therefore been suggested that beta-cells act as pacemakers and that co-ordination among islets is achieved by a neuronal network within the pancreas. Type 2 diabetes mellitus is characterised both by impaired release of insulin and by resistance to the action of insulin. Routine screening procedures for insulin secretion yield little predictive value for later development of diabetes but more sophisticated methods using time-series analysis of diurnal, ultradian and rapid oscillatory insulin secretion reveal the presence of profound defects in glucose-intolerant individuals. Furthermore, studies of rapid pulsatile insulin secretion have revealed defects in glucose-tolerant first-degree relatives of patients with Type 2 diabetes. Application of repeated minimal glucose infusions has further improved the discrimination between insulin release in health and diabetes, suggesting that this method may be suitable for smaller prospective studies of the development of diabetes. Repaglinide, a novel prandial glucose regulator, improves the insulin secretory burst mass in healthy people.

Topics: Carbamates; Circadian Rhythm; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Pancreas; Piperidines; Predictive Value of Tests; Pulsatile Flow

The major contributory factor to increasing hyperglycaemia in established Type 2 diabetes mellitus (T2DM) appears to be the progressive delay and attenuation of the prandial insulin response. An important consequence of this derangement is that hepatic glucose production is no longer suppressed during times of prandial glucose intake. Together with a relative impairment in the rate of peripheral glucose disposal, this leads to supra-physiological plasma glucose excursions, which may damage the vasculature. An obvious therapeutic strategy, therefore, would be to increase insulin availability when most needed--in the early prandial phase. In experiments with exogenous insulin interventions, peak post-prandial blood glucose increments were curtailed without undue increases in total insulin exposure. However, available evidence suggests that the sulphonylurea glibenclamide does not effectively alter early-phase prandial insulin release but predominately increases late-phase and basal insulin output, thus incurring the risk of hypoglycaemia. The novel insulin secretagogue repaglinide, by contrast, augments early-phase prandial insulin secretion when taken before meals, as shown by studies in non-diabetic people and patients with newly diagnosed, previously untreated T2DM. Repaglinide exerts its greatest effect on the insulin secretion rate during the first 30 min after a meal is started, thereby going some way to restoring the early insulin secretion curve seen after a meal in non-diabetic people. No residual secretagogue activity is seen 4 hr after taking a single dose of up to 2 mg. Prandial glucose regulation with repaglinide could be associated with lower post-prandial glucose excursions and less risk of post-prandial hypoglycaemia than glibenclamide.

Topics: Area Under Curve; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Glucose; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Secretion; Kinetics; Liver; Piperidines

Post-prandial hyperglycaemia, which occurs early in the development of impaired glucose tolerance and Type 2 diabetes mellitus (T2DM), has been receiving increased attention recently. Post-prandial hyperglycaemia is likely to promote or aggravate fasting hyperglycaemia and contributes entirely to HbA1c elevation, which is associated with microvascular and macrovascular complications in people with T2DM. Moreover, post-prandial hyperglycaemia is coupled with coagulation activation and may be associated with an increased risk of cardiovascular disease in people with or without diabetes. For these reasons, reduction of post-prandial hyperglycaemia is an important target in patients with impaired glucose tolerance or T2DM. Several treatments have therefore been developed to reduce post-prandial hyperglycaemia; of these, repaglinide, a prandial glucose regulator taken orally before each meal, is now available. Drugs that reduce post-prandial hyperglycaemia significantly also decrease HbA1c (up to 2% with repaglinide) and fasting glucose concentrations (up to 3.9 mmol/l with repaglinide), with consequent decreases in coagulation activation and, in some studies, post-prandial lipidaemia. In clinical trials in patients with T2DM, repaglinide significantly reduced 2-hr post-prandial glucose concentrations and significantly reduced the risk of hypoglycaemia, compared with sulphonylureas, especially when participants missed or postponed a meal. Treatment with the prandial glucose regulator repaglinide allows patients with T2DM to have a more flexible lifestyle, which is likely to improve their quality of life and compliance.

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemic Agents; Patient Compliance; Piperidines; Postprandial Period; Quality of Life

Type 2 diabetes mellitus (T2DM) is a progressive disorder requiring increasingly aggressive treatment to achieve and maintain target blood glucose concentrations in the presence of deteriorating insulin secretion and increasing insulin resistance. Diet and lifestyle modification are often sufficient initially; however, most patients eventually require pharmacological intervention. With disease progression, monotherapy becomes less effective, so combination therapy is required, using drugs with complementary modes of action to maximise glycaemic control. The prandial glucose regulator repaglinide has been studied in combination with metformin (an inhibitor of hepatic glucose production), neutral protamine Hagedorn (NPH)-insulin (which has a long duration of effect, but at the risk of early hypoglycaemia and late hyperglycaemia in the dosing interval) and three thiazolidinediones (TZDs--troglitazone, rosiglitazone and pioglitazone, which stimulate nuclear receptors to increase insulin sensitivity and reduce insulin resistance) in patients whose diabetes was inadequately controlled by previous monotherapy or combination therapy. The combination of repaglinide and metformin resulted in reduced fasting plasma glucose concentrations (by 2.2 mmol/l) and HbA1c (by 1.4%). Combination therapy with repaglinide and bedtime NPH-insulin resulted in reductions in fasting plasma glucose (by 5.4 mmol/l) and HbA1c (by 0.7%). The combination of repaglinide and each TZD also resulted in consistent decreases in fasting plasma glucose concentrations and HbA1c. No severe hypoglycaemic episodes were reported in the three studies. In conclusion, repaglinide has additive, and often synergistic, effects on glycaemic control when given in combination regimens and should be a valuable option in the management of patients with T2DM.

Topics: Carbamates; Chromans; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Insulin; Metformin; Pioglitazone; Piperidines; Postprandial Period; Rosiglitazone; Thiazoles; Thiazolidinediones; Treatment Outcome; Troglitazone

Care of patients with type 2 diabetes has been revolutionized throughout the past several years-first, by the realization of the importance of tight glycemic control in forestalling complications, and second, by the availability of several unique classes of oral antidiabetic agents. Deciphering which agent to use in certain clinical situations is a new dilemma facing the primary care physician.. To systematically review available data from the literature regarding the efficacy of oral antidiabetic agents, both as monotherapy and in combination.. A MEDLINE search was performed to identify all English-language reports of unique, randomized controlled clinical trials involving recently available oral agents for type 2 diabetes. Bibliographies were also reviewed to find additional reports not otherwise identified.. Studies (63) were included in the analysis if they had a study period of at least 3 months; if each group contained at least 10 subjects at the study's conclusion; and if hemoglobin A(1c) was reported. When multiple dosages of a drug were tested, the results of the highest approved dosage were used. In placebo-controlled trials, hemoglobin A(1c) data are presented as the difference between the change in treated vs placebo subjects.. Five distinct oral drug classes are now available for the treatment of type 2 diabetes. Compared with placebo treatment, most of these agents lower hemoglobin A(1c) levels approximately 1% to 2%. Equivalent efficacy is usually demonstrated when different agents are compared with one another in the same study population. When they are used in combination, there are additional glycemic benefits. Long-term vascular risk reduction has been demonstrated only with sulfonylureas and metformin.. With few exceptions, the available oral antidiabetic agents are equally effective at lowering glucose concentrations. Their mechanisms of action are different, however, and as a result they appear to have distinct metabolic effects. These are reflected in their adverse effect profiles and their effect on cardiovascular risk, which may influence drug choice.

Topics: Administration, Oral; Biguanides; Blood Glucose; Carbamates; Chromans; Diabetes Mellitus, Type 2; Diet; Drug Therapy, Combination; Enzyme Inhibitors; Exercise; Glycated Hemoglobin; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Metformin; Piperidines; Randomized Controlled Trials as Topic; Sulfonylurea Compounds; Thiazoles; Thiazolidinediones; Troglitazone

Diabetes is a major and growing health problem in the US. An incredible array of different oral medications is now on the market. Clinicians should understand all these new medications and in which clinical picture they will work best.

Topics: Benzamides; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Metformin; Piperidines; Sulfonylurea Compounds; Thiazoles; Thiazolidinediones

Increasingly, type 2 diabetes takes a toll on public health and healthcare costs in the United States. Although the remedy for this growing problem is very complex, two critical components of its control are prevention and effective therapy. Progress in diabetes prevention is likely to take decades. But fortunately, growth in our understanding of what occurs in this chronic disease has led to advances in the pharmacologic options aimed at decreasing hyperglycemia, the main clinically measurable metabolic consequence of diabetes. In this article, Drs Ahmann and Riddle provide an overview of the oral agents now available for the treatment of diabetes and discuss the clinical factors that help determine when to use which medication and what outcome to expect.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Monitoring; Drug Therapy, Combination; Glycoside Hydrolases; Humans; Hypoglycemic Agents; Metformin; Nateglinide; Phenylalanine; Piperidines; Receptors, Cytoplasmic and Nuclear; Sulfonylurea Compounds; Transcription Factors

Repaglinide is a novel, fast-acting prandial oral hypoglycaemic agent developed for the treatment of patients with type 2 diabetes whose disease cannot be controlled by diet and exercise alone. Although repaglinide binds to the sulphonylurea binding sites on pancreatic beta-cells and has a similar mechanism of action, repaglinide exhibits distinct pharmacological properties compared with these agents. Following administration, repaglinide is absorbed rapidly and has a fast onset of dose-dependent blood-glucose lowering effect. The drug is eliminated rapidly via the biliary route, without accumulation in the plasma after multiple doses. Repaglinide is well tolerated in patients with type 2 diabetes, including elderly patients and patients with hepatic or renal impairment. The pharmacokinetic profile of repaglinide and the improvements in post-prandial hyperglycaemia and overall glycaemic control make repaglinide suitable for administration preprandially, with the opportunity for flexible meal arrangements, including skipped meals, without the risk of hypoglycaemia.

Topics: Adult; Aged; Blood Glucose; Carbamates; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug Interactions; Female; Humans; Hypoglycemic Agents; Liver Diseases; Male; Piperidines; Renal Insufficiency; Rifampin

Topics: Carbamates; Humans; Hyperglycemia; Hypoglycemic Agents; Piperidines; Postprandial Period; Treatment Outcome

Topics: Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemia; Hypoglycemic Agents; Patient Compliance; Piperidines; Postprandial Period; Randomized Controlled Trials as Topic

Topics: Carbamates; Chromans; Diabetes Mellitus, Type 2; Drug Synergism; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Insulin, Isophane; Metformin; Piperidines; Thiazoles; Thiazolidinediones; Troglitazone

The loss of early insulin secretion appears to be a critical event in the deterioration in glucose tolerance during the development of type 2 diabetes. There is therefore a strong rationale for developing new antidiabetic agents aimed at restoring or replacing early prandial insulin secretion and thereby curbing mealtime glucose excursions in patients with type 2 diabetes. Four such new agents are either now available (repaglinide and nateglinide) or in clinical development (KAD-1229 and BTS 67 582). Preclinical studies suggest that each of these new insulinotropic agents share a common receptor/effector mechanism with the sulfonylureas (SUs) but that each may have distinct characteristics that differentiate them from the SUs and from each other. Nateglinide and KAD-1229 clearly stimulate biphasic insulin secretion in vitro and in vivo and their effects are rapidly reversible, whereas the effects of repaglinide and BTS 67 582 are prolonged well beyond their removal from perfusion media in vitro or their clearance in vivo. Available data from human studies indicate that the pharmacokinetics of repaglinide and nateglinide are similar, i.e., they are both rapidly absorbed and eliminated, but consistent with findings from animal studies, the insulinotropic and glucose-lowering effects of repaglinide are slower in onset and more prolonged than those of nateglinide. Repaglinide and nateglinide have been shown to be safe and well-tolerated in patients with type 2 diabetes and to produce clinically-meaningful reductions of HbA1c, both alone and in combination with agents with complementary modes of action (e.g., metformin and thiazolidinediones). Because these new agents can potentially bring patients to near normoglycemia without an undue risk of hypoglycemia, they are important additions to the therapeutic armamentarium.

Topics: Animals; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glucose; Guanidines; Humans; Hypoglycemic Agents; Indoles; Insulin; Insulin Secretion; Isoindoles; Nateglinide; Phenylalanine; Piperidines

In about 25% of type 2 diabetes patients, good diabetes control is not attainable with oral blood-glucose lowering drugs. Furthermore, in many people with diabetes the disease deteriorates, despite the use of blood-glucose lowering medication, due to the decline of the pancreatic beta cells. The development of new drugs, such as repaglinide, is therefore important. Repaglinide is an insulin secretion enhancer with a different mechanism of action to the sulphonylureas, which means it does not continuously stimulate insulin secretion. The tablets should be taken with each meal. After oral ingestion repaglinide is resorbed quickly, with a half-life of between 30 minutes to an hour. In clinical trials repaglinide has been found to be equally effective as glibenclamide. Repaglinide has been found to be particularly effective in sulphonylurea-naïve patients. Skipping the meal plus tablet combination results in less frequent hypoglycaemic symptoms compared to glibenclamide. Repaglinide results in greater reductions in postprandial glucose levels than glibenclamide. It does not affect insulin resistance. Long-term data are lacking, both with regard to efficacy and side effects. Repaglinide deserves a place in the diabetes treatment of newly-diagnosed type 2 diabetes patients who are well-informed about their disease, as well as in patients with renal failure. It should also be considered for patients whose diabetes is poorly controlled on metformin monotherapy.

Topics: Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glyburide; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Secretion; Metformin; Piperidines; Therapeutic Equivalency

United Kingdom Prospective Diabetes Study (UKPDS) has demonstrated definitively that patients with type 2 diabetes mellitus (DM) benefit from intensive blood glucose control, because it diminishes the risk to develop microvascular complications. The therapeutic targets in the type 2 DM have been modified in order to reduce the risk of these complications. However, aggressive treatment may be disastrous for patients with microvascular complications and/or an increased risk of hypoglycemic unawareness, and neither it would be advised in older patients or with short life expectancy. The available drugs for treatment of type 2 DM offer many options for achieving these therapeutic targets, based on the need of the individual patient. In this job we review the targets in the metabolic control of type 2 DM and their backgrounds, and we describe briefly the therapeutic strategy recommended for reaching these targets, with special attention to the new oral antidiabetic agents (repaglinide and thiazolidinediones).

Topics: Carbamates; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Humans; Hyperinsulinism; Hypoglycemic Agents; Insulin Resistance; Piperidines; Thiazoles

Repaglinide, a carbamoylmethyl benzoic acid derivative, is the first of a new class of oral antidiabetic agents designed to normalise postprandial glucose excursions in patients with type 2 diabetes mellitus. Like the sulphonylureas, repaglinide reduces blood glucose by stimulating insulin release from pancreatic beta-cells, but differs from these and other antidiabetic agents in its structure, binding profile, duration of action and mode of excretion. In clinical trials of up to 1-year's duration, repaglinide maintained or improved glycaemic control in patients with type 2 diabetes mellitus. In comparative, 1-year, double-blind, randomised trials (n = 256 to 544), patients receiving repaglinide (0.5 to 4mg before 3 daily meals) achieved similar glycaemic control to that in patients receiving glibenclamide (glyburide) < or = 15 mg/day and greater control than patients receiving glipizide < or = 15 mg/day. Changes from baseline in glycosylated haemoglobin and fasting blood glucose levels were similar between patients receiving repaglinide and glibenclamide in all studies; however, repaglinide was slightly better than glibenclamide in reducing postprandial blood glucose in I short term study (n = 192). Patients can vary their meal timetable with repaglinide: the glucose-lowering efficacy of repaglinide was similar for patients consuming 2, 3 or 4 meals a day. Repaglinide showed additive effects when used in combination with other oral antidiabetic agents including metformin, troglitazone, rosiglitazone and pioglitazone, and intermediate-acting insulin (NPH) given at bedtime. In 1-year trials, the most common adverse events reported in repaglinide recipients (n = 1,228) were hypoglycaemia (16%), upper respiratory tract infection (10%), rhinitis (7%), bronchitis (6%) and headache (9%). The overall incidence of hypoglycaemia was similar to that recorded in patients receiving glibenclamide, glipizide or gliclazide (n = 597) [18%]; however, the incidence of serious hypoglycaemia appears to be slightly higher in sulphonylurea recipients. Unlike glibenclamide, the risk of hypoglycaemia in patients receiving repaglinide was not increased when a meal was missed in 1 trial. In conclusion, repaglinide is a useful addition to the other currently available treatments for type 2 diabetes mellitus. Preprandial repaglinide has displayed antihyperglycaemic efficacy at least equal to that of various sulphonylureas and is associated with a reduced risk of serious hypoglycaemi

Topics: Administration, Oral; Adult; Aged; Aging; Animals; Biological Availability; Blood Glucose; Carbamates; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug Interactions; Glycated Hemoglobin; Half-Life; Humans; Hypoglycemic Agents; Intestinal Absorption; Metabolic Clearance Rate; Piperidines

Presentation of six drugs: clopidogrel, raloxifene, mecillinam, natiglinide and repaglinide, pneumococcal conjugate vaccine. For each, positive and negative arguments, questions on hold and rating.

Topics: Amdinocillin; Carbamates; Clopidogrel; Cyclohexanes; Drug Interactions; Humans; Hypoglycemic Agents; Nateglinide; Patient Selection; Penicillins; Phenylalanine; Piperidines; Platelet Aggregation Inhibitors; Pneumococcal Vaccines; Raloxifene Hydrochloride; Safety; Selective Estrogen Receptor Modulators; Ticlopidine

In this article two new peroral antidiabetics are introduced. The first is repaglinide, a prandial glucose regulator. The second is rosiglitazone, a member of the thiazolidinediones family, which improves the sensitivity of tissues to insulin and reduces insulin resistance.

Topics: Administration, Oral; Carbamates; Diabetes Mellitus; Humans; Hypoglycemic Agents; Pioglitazone; Piperidines; Rosiglitazone; Thiazoles; Thiazolidinediones

The loss of early-phase insulin secretion is an important and early event in the natural history of type 2 diabetes. Because a normal pattern of insulin secretion is essential for the effective control of postprandial metabolism, a rational basis for the development of agents that target early-phase insulin release exists. Conventional oral hypoglycaemic agents do not target, or adequately control, postprandial glycaemia. The emergence of new classes of oral agent with a more specific mode of action provides, for the first time, an opportunity to restore early-phase insulin release. One such drug class is the meglitinide analogues (repaglinide, nateglinide, and mitiglinide). These drugs are ideally suited for combination use with metformin. They could also prove effective in combination with a thiazolidinedione, a drug class that targets insulin resistance. Exogenous insulin is frequently required in the late management of type 2 diabetes. However, one hope for newer combinations of diabetic drugs is that the functional life of the beta cell can be extended, thereby delaying the need for insulin injections.

Topics: Adult; Animals; Benzamides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Nateglinide; Phenylalanine; Piperidines; Rats

The complications of diabetes mellitus, arising from inadequate glycemic control, have serious consequences for society as well as individuals. It is now urged that tight glycemic control be the goal for all patients, regardless of type of diabetes. Unfortunately, hypoglycemia can be a consequence of this aggressive approach. Treatment with a combination of agents and improved therapies are needed to maintain glycemic balance in patients. A better understanding of the pathophysiology of diabetes has yielded many treatment options based on various mechanisms of action. The sulfonyluereas, repaglinide, metformin, acarbose and the thiazolidinediones are effective in decreasing fasting plasma glucose levels, but their limitations may include adverse effects, such as weight gain and hypoglycemia, and an inability to modify some of the important comorbidities of diabetes. Therapies aimed at treating mealtime hyperglycemia are gaining attention. One promising investigational agent in this category is nateglinide. Early data suggest that its rapid onset and short duration of action result in increased early mealtime insulin release, reduced mealtime glucose excursions, and improved glycemic control.

Topics: Acarbose; Administration, Oral; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Combinations; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Secretion; Insulin-Secreting Cells; Metformin; Nateglinide; Phenylalanine; Piperidines; Randomized Controlled Trials as Topic; Thiazolidinediones; United States; Weight Gain

Type 2 diabetes mellitus is a progressive disorder, and although oral monotherapy is often initially successful, it is associated with a high secondary failure rate, which contributes to the development of long-term diabetes complications resulting from persistent hyperglycemia. For patients not taking insulin, accumulating evidence suggests that combination therapy using oral antidiabetic agents with different mechanisms of action may be highly effective in achieving and maintaining target blood glucose levels. Low-dose combination therapy may be associated with fewer side effects than higher-dose monotherapy and may achieve similar or better glycemic control. The best-studied combination is that of sulfonylurea compounds plus metformin, a therapeutic approach that addresses both underlying defects in the disorder: insulin deficiency and insulin resistance. Other multidrug regimens under investigation are sulfonylurea compounds plus either alpha-glucosidase inhibitors or thiazolidinediones, and combinations of various insulin-sensitizing agents. For many patients, combination oral therapy may be used appropriately as primary management early in the course of type 2 diabetes, along with diet modification and exercise. Later in the course of the disease, the use of combinations of oral agents may delay the need for insulin while maintaining glycemic control, thus making aggressive oral treatment more acceptable for many patients.

Topics: Acarbose; Administration, Oral; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug Therapy, Combination; Glyburide; Humans; Hypoglycemic Agents; Metformin; Piperidines; Sulfonylurea Compounds

A central finding of the UKPDS was that in type 2 diabetic patients, tight glycemic control with HbA1c targets as close to the normal range as possible must be achieved to further reduce diabetes related-complications, -mortality, and -cardiovascular disease, highlighting the need for new, optimized treatment strategies. With a focus on clinical efficacy, this paper discusses the results from the 20 major therapeutical trials published in the years 1997-1999, that evaluated the new insulinsensitizing thiazolidinediones Rosiglitazone and Pioglitazone and the new insulin-releasing potassium channel blockers Repaglinide and Nateglinide. While for Nateglinide, promising, but only preliminary data is available at current, Rosiglitazone, Pioglitazone, and Repaglinide have been shown appropriate for both mono- and combination therapy with current standard drug treatment of type 2 diabetes. Similar to the known, older antidiabetic drugs, the new agents discussed have comparable blood glucose lowering potentials with a dose-related capacity of 0.5 to 1.5% HbA1c reduction. These beneficial effects were both seen in drug-naive patients previously treated with diet only and in combination therapies where patients had previous antidiabetic standard drug treatment suggesting effectiveness of glitazones and glinides also in more advanced stages of the disease. Problems with adverse effects appeared minor although long-range implications of weight gain, edema, lowering of hemoglobin, increase of total cholesterol for the glitazones, and hypoglycemia for glinides warrant further consideration. What becomes clear from the variety of most recent mono- and combination treatment studies with as much as five different classes of antidiabetic drugs is that individually tailored therapies that recognize quality of life parameters and target the predominant features of metabolic pathology (such as early postprandial versus fasting hyperglycemia, degree of insulin resistance, progressive loss of 1-cell function) may become a feasible goal in the future.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Pioglitazone; Piperidines; Rosiglitazone; Thiazoles; Thiazolidinediones

Repaglinide (NovoNorm((R))) is a novel oral antidiabetic agent, the first of a new class of insulin secretagogues known as the prandial glucose regulators to be approved for use in patients with Type 2 diabetes. Prandial glucose regulation is aimed at restoring the first-phase insulin response that follows consumption of a meal, which is missing in patients with Type 2 diabetes. After repaglinide administration, the resulting insulin profile reflects that of healthy individuals more closely, providing tighter glycaemic control and reducing the risk of hypoglycaemic events. Repaglinide is quickly absorbed and rapidly eliminated through biliary excretion, making it suitable for use in patients with renal impairment. It appears in the bloodstream within 15 to 30 min of dosing, stimulating short-term insulin release from the pancreatic beta-cells by binding to a unique site on the beta-cell membrane. Rapid elimination ensures that postprandial insulin levels quickly return to preprandial levels as the high prandial glucose level subsides. Repaglinide is given on a 'one meal, one tablet; no meal, no tablet' basis. It is particularly effective in patients who have not previously been treated with an oral antidiabetic agent, significantly reducing glycosylated haemoglobin (HbA(1c)) levels by 1.6%. It also offers increased mealtime flexibility and safety, compared with other oral antidiabetic agents. As a result of the short plasma half-life and lack of accumulation of repaglinide with repeated dosing, the risk of between-meal and nocturnal hypoglycaemia is substantially reduced compared with other oral antidiabetic agents. Repaglinide acts synergistically with metformin, consistently improving glycaemic control in patients who were insufficiently controlled by metformin alone. Results from recent studies have shown similar synergistic effects with neutral protamine Hagedorn (NPH)-insulin or troglitazone.

Topics: Animals; Carbamates; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Eating; Humans; Hypoglycemic Agents; Piperidines

Type 2 diabetes mellitus is characterised by abnormal beta-cell function (present at the time of diagnosis) that is often associated with insulin resistance. An important and consistent pathophysiological finding is the failure to produce adequate increments in insulin secretion in response to carbohydrate intake. Therefore, insulin secretagogue therapy, particularly when focused on prandial glucose regulation, is a logical approach to treatment because it addresses one of the most fundamental pathophysiological aspects of the disease. However, the traditional secretagogues-the sulphonylureas--have long been associated with the unwanted effect of hypoglycaemia. This is particularly likely to occur when drugs with lengthy plasma half-lives, prolonged drug-receptor interactions, active metabolites or a reliance on renal clearance are used. The problem is most prevalent in elderly patients, where sulphonylurea-induced hypoglycaemia may be related to failure to comply with strict mealtimes or the need for supplementary food intake, often in the context of compromised renal function. Data from large-scale outcome studies demonstrate that when tight glycaemic control is achieved through aggressive antidiabetic therapy, late diabetic complications can be significantly reduced. However, the pursuit of stricter HbA1c targets with more aggressive interventions may increase the risk of hypoglycaemia. This is an irony because the clinical need to avoid hypoglycaemia and patients' apprehension of it present barriers to the achievement of beneficial glycaemic targets. However, an increased risk of hypoglycaemia may not be inevitable with insulin secretagogue therapy. The recently introduced carbamoylmethyl benzoic acid derivative, repaglinide, has pharmacological properties that are well suited to its intended role as a prandial glucose regulator. When taken prior to main meals, the rapid onset and relatively short duration of action of repaglinide aid disposal of the mealtime glucose load, without continued stimulation of pancreatic beta-cells in the postprandial fasting period. Repaglinide is also characterised by hepatic metabolism and elimination, which is an advantage in the context of impaired renal function. Prandial glucose regulation with repaglinide selectively increases insulin secretion, and hence limits glucose excursions, in the prandial phase. If a meal is omitted, so too is the corresponding dose. This more flexible approach to the management of Type 2

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Eating; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Secretion; Patient Compliance; Piperidines; Risk Factors; Sulfonylurea Compounds; Time Factors

Type 2 diabetes is characterised by a progressive deterioration of the prandial insulin response, in a situation of continuing insulin resistance. Early phase insulin release is attenuated and delayed and there is a consequent failure to suppress glucagon secretion and curtail hepatic glucose production and gluconeogenesis. Postprandial plasma glucose concentration rises to pathological levels and fails to return to normal before the patient consumes their next meal, creating a problem of continuous daytime hyperglycaemia. Although late insulin secretion is preserved it does not rectify the hyperglycaemia. The pathology of excessive prandial glucose excursions and continual daytime hyperglycaemia can be normalised, at least in part, if early-phase insulin availability is restored through pharmacologic intervention. Initially, the feasibility of this approach was demonstrated experimentally with the use of carefully controlled insulin infusions or insulin analogue injections. More recently, the availability of the rapid or early augmentor of insulin secretion--repaglinide--provides a means for restoring prandial glucose regulation with oral therapy. Placebo-controlled and oral hypoglycaemic agent (OHA) comparative studies of repaglinide have established its antidiabetic efficacy and flexible mealtime/dosing studies have confirmed the importance of the prandial approach to treatment. Prandial glucose regulation with repaglinide has also been demonstrated to provide synergies when used as combination therapy with insulin sensitising agents. As a strategy, prandial glucose regulation has a number of theoretical advantages over the use of fixed doses of conventional insulin secretagogues, and these have been borne out in clinical trials. As well as offering a more flexible approach to treatment, prandial repaglinide is associated with a reduced risk of severe hypoglycaemia.

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Eating; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Piperidines; Time Factors

The importance of glucose control in reducing the complications of diabetes mellitus has been clearly demonstrated. The emergency physician routinely is expected to treat a wide range of problems related to this disease, including making the initial diagnosis of type 2 and occasionally type 1 diabetes. Also common are patients with poorly controlled diabetes. The recent introduction of new classes of agents to lower blood glucose, especially in type 2 diabetes, should improve the control in this category of patient and reduce the complication rate. Some of these agents, such as troglitazone, have potentially fatal complications and require careful monitoring. Emergency physicians should be aware of the common complications of these drugs because patients can present to the ED with them. Hypoglycemia, a common cause of 911 calls and emergency visits, is not a side effect of either metformin or acarbose. Insulin lispro has improved postprandial glycemic control for type 1 and some insulin-requiring type 2 diabetics. Hypoglycemia is less of a risk with insulin lispro, and quality of life is better with this rapidly acting insulin. Newer methods of insulin delivery, such as continuous subcutaneous infusion, have greatly improved glucose control, given greater freedom to patients, and reduced the risks of hypoglycemia.

Topics: Acarbose; Administration, Oral; Carbamates; Chromans; Diabetes Mellitus; Drug Overdose; Emergencies; Humans; Hypoglycemic Agents; Insulin; Insulin Lispro; Metformin; Piperidines; Sulfonylurea Compounds; Thiazoles; Thiazolidinediones; Troglitazone

Type 2 diabetes mellitus is a complex heterogenous metabolic disorder in which peripheral insulin resistance and impaired insulin release are the main pathogenetic factors. The rapid response of the pancreatic beta-cells to glucose is already markedly disturbed in the early stages of type 2 diabetes mellitus. The consequence is often postprandial hyperglycaemia, which seems to be extremely important in the development of secondary complications, especially macrovascular disease. Therefore one of the main aims of treatment is to minimise blood glucose oscillations and attain near-normal glycosylated haemoglobin levels. Meglitinide analogues belong to a new family of insulin secretagogues which stimulate insulin release by inhibiting ATP-sensitive potassium channels of the beta-cell membrane via binding to a receptor distinct from that of sulphonylureas (SUR1/KIR 6.2). The pharmacokinetic and pharmacodynamic properties of repaglinide, the first drug of these new antihyperglycaemic agents on the market, and of nateglinide, which will be available soon, differ markedly from the currently used sulphonylureas [mainly glibenclamide (glyburide) and glimepiride]. Repaglinide and nateglinide are absorbed rapidly, stimulate insulin release within a few minutes, are rapidly metabolised in the liver and are mainly excreted in the bile. Therefore, following preprandial administration of these drugs, insulin is more readily available during and just after the meal. This leads to a significant reduction in postprandial hyperglycaemia without the danger of hypoglycaemia between meals. The short action of these compounds and biliary elimination makes repaglinide and nateglinide especially suitable for patients with type 2 diabetes mellitus who would like to have a more flexible lifestyle, need more flexibility because of unplanned eating behaviour (e.g. geriatric patients) or in whom one of the other first-line antidiabetic drugs, i.e. metformin, is strictly contraindicated (e.g. nephropathy with creatinine clearance < or = 50 ml/min). Meglitinide analogues act synergistically with metformin and thiazolidinediones (pioglitazone and rosiglitazone) and can be also combined with long-acting insulin (NPH insulin at bedtime). Therefore, these drugs enrich the palette of antidiabetic drugs and make the treatment more flexible and better tolerated, which both add to better metabolic control and support the empowerment and compliance of the patient. However, this will only be the

Topics: Benzamides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glyburide; Humans; Hypoglycemic Agents; Molecular Structure; Nateglinide; Phenylalanine; Piperidines

Prandial glucose regulation represents a new concept in the management of type 2 diabetes: targeting postprandial glycaemic excursions as a means of achieving long-term glycaemic control. Although control of the overall glycaemic load is the most important factor for the success of long-term management of type 2 diabetes, control of postprandial hyperglycaemia also has positive implications for preventing the development of diabetic complications. Repaglinide is the first prandial glucose regulator to become available in the clinical setting. It has a rapid and short-lived insulinotropic action and can therefore reduce postprandial glucose excursions without increasing the risk of hypoglycaemia. Short-term clinical studies showed that repaglinide is superior to glibenclamide in improving postprandial glycaemic control. Longer-term studies confirmed that improved PGR is accompanied by improved overall glycaemic control that is at least equivalent to that achieved by sulphonylurea treatment. Moreover, because repaglinide can be used with flexible meal patterns without compromising glucose control, it can improve quality of life as indicated by overall treatment satisfaction, well-being and health status. Repaglinide has few contraindications or drug interactions and can be used in a wide range of patients. Although careful titration of repaglinide dose is recommended for patients with mild to moderate renal impairment, no dosage adjustment is otherwise needed in the elderly. In addition to being an effective first-line hypoglycaemic agent, repaglinide is highly effective in combination therapy for patients with type 2 diabetes who require more intensive treatment. When glucose targets are not met using repaglinide monotherapy, the combination of repaglinide with metformin can further improve glycaemic control by enhancing insulin secretion and improving insulin sensitivity. Similarly, when required combination of repaglinide with troglitazone or NPH-insulin can produce better glycaemic control than monotherapy alone. Given that most patients with type 2 diabetes require a multitherapy approach to achieve and sustain adequate glycaemic control, repaglinide will be an important element in future intensive therapy regimens.

Topics: Carbamates; Drug Therapy, Combination; Humans; Hyperglycemia; Hypoglycemic Agents; Piperidines; Postprandial Period; Safety; Time Factors; Treatment Outcome

Repaglinide is a novel insulin secretagogue that was developed as a prandial glucose regulator for the treatment of people with Type 2 diabetes mellitus. It is used flexibly, taken prior to meals, in order to limit subsequent postprandial blood glucose excursions as well as the dependent basal blood glucose concentration. In theory, the pharmacological profile of repaglinide is well suited for this role. Taken at mealtimes, its relatively rapid-onset and short-duration of action counteract a fundamental pathophysiological aspect of this disease: attenuation of the prandial insulin response. The predominantly hepatic elimination profile and a lack of drug-drug interactions with repaglinide are also properties well suited for patients with Type 2 diabetes. Importantly, the pharmacokinetic properties of repaglinide, are expected to reduce the risk of hypoglycaemia in comparison to the conventional insulin secretagogues (sulphonylureas). A reduced risk of hypoglycaemia carries the advantage that patients are not obliged to consume meals at regular intervals supplemented by snacks, so caloric restriction is feasible and lifestyle not compromised. These theoretical advantages have now been largely borne-out by clinical studies and empirical experience. Placebo-controlled studies have consistently demonstrated the antidiabetic efficacy of repaglinide, with improvements having been shown in all indicators of glycaemic control. Double-blind, active-comparator studies have shown repaglinide to have an antidiabetic efficacy that is at least equivalent to sulphonylureas, even when food intake and dosing intervals were controlled according to the requirements of sulphonylureas. Pooled data from these studies have shown that the risk of severe hypoglycaemia is reduced by 60% (p = 0.03) when repaglinide is used in preference to sulphonylureas. There is also evidence that the blood glucose threshold at which symptoms of hypoglycaemia are perceived by patients may be better preserved during treatment with repaglinide than with sulphonylureas. Studies examining flexible prandial dosing with repaglinide have shown that good glycaemic control and a low risk of hypoglycaemia are achievable goals that are independent of the meal (and, hence, dosing) pattern chosen by the patient. Furthermore, when used in this way, repaglinide has not been associated with weight gain. In combination therapy, repaglinide has been shown to act in synergy with both metformin and troglitazone. The

Topics: Blood Glucose; Carbamates; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Piperidines; Postprandial Period

It is widely accepted that the most challenging goal in the management of patients with diabetes mellitus is to achieve blood glucose levels as close to normal as possible. In general, normalising postprandial blood glucose levels is more difficult than normalising fasting hyperglycaemia. In addition, some epidemiological studies suggest that postprandial hyperglycaemia (PPHG) or hyperinsulinaemia are independent risk factors for the development of macrovascular complications of diabetes mellitus. Recently, several drugs with differing pharmacodynamic profiles have been developed which target PPHG. These include insulin lispro, amylin analogues, alpha-glucosidase inhibitors and meglitinide analogues. Insulin lispro has a more rapid onset of action and shorter duration of efficacy compared with regular human insulin. In clinical trials, the use of insulin lispro was associated with improved control of PPHG and a reduced incidence of hypoglycaemic episodes. Repaglinide, a meglitinide analogue, is a short-acting insulinotropic agent which. when given before meals, stimulates endogenous insulin secretions and lowers postprandial hyperglycaemic excursions. Both insulin lispro and repaglinide are associated with postprandial hyperinsulinaemia. In contrast, amylin analogues reduce PPHG by slowing gastric emptying and delivery of nutrients to the absorbing surface of the gut. Alpha-Glucosidase inhibitors such as acarbose, miglitol and voglibose also reduce PPHG primarily by interfering with the carbohydrate-digesting enzymes and delaying glucose absorption. With the availability of agents which preferentially reduce postprandial blood glucose excursions, it is now possible to achieve glycaemic goals in a larger proportion of individuals with diabetes mellitus.

Topics: 1-Deoxynojirimycin; Acarbose; Amyloid; Carbamates; Diabetes Mellitus; Enzyme Inhibitors; Glucosamine; Glyburide; Humans; Hyperglycemia; Hypoglycemic Agents; Imino Pyranoses; Inositol; Insulin; Insulin Lispro; Islet Amyloid Polypeptide; Piperidines; Postprandial Period; Trisaccharides

Repaglinide is a new carbamoylmethyl benzoic acid derivative that is structurally related to meglitinide. In common with all active oral hypoglycaemic agents, it displays a comparable U-shaped configuration. Repaglinide exerts its effects by binding to a site on the plasma membrane of beta-cells, thereby closing ATP-sensitive potassium channels. This causes depolarization of the beta-cell and the opening of voltage-sensitive calcium channels allowing the influx of extracellular calcium ions. This increase in intracellular calcium, in turn, stimulates insulin release. The insulinotropic effect of repaglinide is not related to its ionophoretic capacity. Repaglinide does not cause insulin release in the absence of exogenous glucose, nor does it inhibit the biosynthesis of proinsulin. In vivo administration of an ester of succinic acid potentiates the insulin secretory response to concomitantly administered repaglinide. Repaglinide causes a more rapid increase in plasma insulin levels in rats than either glibenclamide or glimepiride.

Topics: Administration, Oral; Animals; Carbamates; Diabetes Mellitus, Type 2; Hypoglycemic Agents; Piperidines; Rats

Repaglinide, a carbamoylmethyl benzoic acid derivative, is rapidly absorbed, metabolized by the liver and eliminated primarily via the bile. It has a short duration of action and is taken immediately before each main meal. This regimen has been shown to provide superior glycaemic control compared with regular morning and evening dosing. A flexible preprandial only dosing regimen of repaglinide significantly lowers the risk of hypoglycaemia if a meal is missed or postponed. Combination therapy with metformin improves glycaemic control significantly compared with therapy with either drug alone in overweight patients. Repaglinide has an equivalent safety and efficacy profile to the sulphonylureas, although it is superior to glipizide in maintaining long-term glycaemic control The postprandial glucose levels are significantly lower with repaglinide compared with glibenclamide. In naive patients with Type 2 diabetes, repaglinide lowers fasting glucose concentrations and functions also as a prandial glucose regulator.

Topics: Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Piperidines

Type 2 diabetes mellitus is a chronic metabolic disorder that results from defects in both insulin secretion and insulin action. An elevated rate of basal hepatic glucose production in the presence of hyperinsulinemia is the primary cause of fasting hyperglycemia; after a meal, impaired suppression of hepatic glucose production by insulin and decreased insulin-mediated glucose uptake by muscle contribute almost equally to postprandial hyperglycemia. In the United States, five classes of oral agents, each of which works through a different mechanism of action, are currently available to improve glycemic control in patients with type 2 diabetes. The recently completed United Kingdom Prospective Diabetes Study (UKPDS) has shown that type 2 diabetes mellitus is a progressive disorder that can be treated initially with oral agent monotherapy but will eventually require the addition of other oral agents, and that in many patients, insulin therapy will be needed to achieve targeted glycemic levels. In the UKPDS, improved glycemic control, irrespective of the agent used (sulfonylureas, metformin, or insulin), decreased the incidence of microvascular complications (retinopathy, neuropathy, and nephropathy). This review examines the goals of antihyperglycemic therapy and reviews the mechanism of action, efficacy, nonglycemic benefits, cost, and safety profile of each of the five approved classes of oral agents. A rationale for the use of these oral agents as monotherapy, in combination with each other, and in combination with insulin is provided.

Topics: Acarbose; Administration, Oral; Algorithms; Carbamates; Chromans; Diabetes Mellitus, Type 2; Evidence-Based Medicine; Humans; Hypoglycemic Agents; Insulin; Metformin; Piperidines; Sulfonylurea Compounds; Thiazoles; Thiazolidinediones; Trisaccharides; Troglitazone

The action of repaglinide, a carbamoylmethyl benzoic acid derivative, mimics the physiological insulin secretion that is deficient in Type 2 diabetes mellitus. Repaglinide stimulates insulin release from beta-cells only in the presence of glucose. Two placebo-controlled studies were performed to establish the effective dose range of repaglinide. In one study, repaglinide (0.25-4.0 mg preprandially) caused a dose-dependent decrease in blood glucose and a non-dose-dependent increase in insulin over 4 weeks (all doses p < 0.001 vs. placebo). In the second study, repaglinide (0.25-8.0 mg preprandially) was titrated over 6 weeks to obtain the optimum response (fasting plasma glucose < 8.9 mmol/L). The titration period was followed by a 12-week dose-maintenance period. At the end of the study, repaglinide had decreased fasting plasma glucose by 3.4 mmol/L (p < 0.05) and 2-h postprandial blood glucose by 5.8 mmol/L (p < 0.001) versus placebo. Glycated haemoglobin (HbA1c) decreased significantly from 8.5% to 7.9% in the repaglinide group and increased significantly from 8.1% to 9.2% in the placebo group (p < 0.001 between groups). In five 1-year, multicentre, randomized, double-blind, phase III trials, repaglinide (0.5-4.0 mg preprandially) was compared with the sulphonylureas glibenclamide, glipizide and gliclazide. Repaglinide was more effective than glipizide at maintaining glycaemic control and was equivalent to glibenclamide and gliclazide on the basis of change in HbA1c. Hypoglycaemic events were reported in 16% of repaglinide-treated patients and 15-20% of sulphonylurea-treated patients. These data indicate that repaglinide monotherapy, with diet and exercise, is effective in patients with Type 2 diabetes.

Topics: Blood Glucose; Carbamates; Controlled Clinical Trials as Topic; Diabetes Mellitus, Type 2; Food; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Piperidines

Repaglinide, a carbamoylmethyl benzoic acid (CMBA) derivative, belongs to a new class of antidiabetic agents structurally related to meglitinide (previously known as the non-sulphonylurea moiety of glibenclamide). Repaglinide and glibenclamide exert reciprocal competitive effects on their respective binding to insulinoma cells. Repaglinide does not affect the metabolism of D-glucose or endogenous nutrients or the biosynthesis of peptides in isolated rat pancreatic islets. Repeated intragastric administration of repaglinide to normal rats increases basal and glucose-stimulated peptide biosynthesis in isolated islets. The major primary action of repaglinide in islets is the closure of ATP-sensitive K+ channels. This agent decreases 86Rb outflow from prelabelled islets perifused in the absence of any exogenous nutrient and protects beta-cells against the inhibitory action of a diazoxide analogue on glucose-stimulated insulin release. The decrease in K+ conductance coincides with stimulation of Ca2+ influx into the islet cells. Meglitinide and its analogues stimulate insulin release more efficiently in the presence of D-glucose or other nutrient secretagogues than in their absence. They are efficient insulinotropic agents in animal models of Type 2 diabetes or in animals infused for 48 h with a hypertonic solution of D-glucose. Repaglinide augments somatostatin secretion, without affecting glucagon release, in isolated perfused rat pancreases exposed to D-glucose. The insulinotropic action of repaglinide was documented in vivo after intravenous or oral administration in normal or Goto-Kakizaki rats. These preclinical investigations suggest that these new insulin secretagogues are well suited as potential insulinotropic tools in the treatment of Type 2 diabetes.

Topics: Animals; Blood Glucose; Calcium; Carbamates; Electric Conductivity; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Piperidines; Potassium; Rats

Repaglinide, an insulinotropic benzoic acid derivative, has been tested extensively in the preclinical and clinical setting for safety and tolerability. In preclinical safety trials, no clinically relevant laboratory or histopathological changes were found and repaglinide was not found to be genotoxic, immunogenic, teratogenic or tumorigenic at levels 50 times greater than the exposure in humans. In an ascending-dose tolerability study in Type 2 diabetic patients, no clinically relevant changes in liver enzymes or ECG occurred during the trial. A total of five active-controlled, long-term trials of identical design have been carried out (with 12 months of maintenance on a fixed, pretitrated dose), including 1228 patients on repaglinide and 597 on sulphonylureas, 417 of whom were on glibenclamide. The most common adverse event in the phase II studies was hypoglycaemia. The frequency of hypoglycaemia was identical for repaglinide and sulphonylureas; however, fewer nocturnal hypoglycaemic events were observed with repaglinide and no increase in the frequency of hypoglycaemic events occurred in elderly patients (> 65 years) compared with younger patients. Severe reactions (assistance required) were approximately twice as frequent in the comparator group. During these studies, two serious hypoglycaemic reactions were reported (coma, seizure or hospitalization), both occurring in patients on glibenclamide. The frequency of serious adverse events and serious cardiovascular events was comparable between repaglinide and sulphonylureas.

Topics: Aged; Animals; Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemia; Hypoglycemic Agents; Piperidines; Randomized Controlled Trials as Topic

Secretatogues are a class of agents that achieve their hypoglycemic effects through stimulating insulin release. They include the sulfonylureas, repaglinide, and the investigational agent glucagon-like peptide. The secretagogue agents have been studied extensively as monotherapy and in conjunction with other classes of oral agents, including alpha-glucosidase inhibitors, bijuanides, and thiazolidinediones, for the treatment of type 2 diabetes. This article reviews the pharmacodynamic and pharmacokinetic differences of the secretagogues, as well as the most recent clinical trials. Such information should be helpful when deciding which agent or agents will yield the best glycemic control for an individual patient.

Topics: Acarbose; Carbamates; Chromans; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glucagon; Glucagon-Like Peptide 1; Humans; Hypoglycemic Agents; Metformin; Peptide Fragments; Piperidines; Protein Precursors; Risk Factors; Sulfonylurea Compounds; Thiazoles; Thiazolidinediones; Troglitazone

Topics: Carbamates; Chromans; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin Resistance; Metformin; Nateglinide; Phenylalanine; Piperidines; Thiazoles; Thiazolidinediones; Troglitazone

Repaglinide is a new oral blood glucose lowering agent, a member of the carbamoylmethyl benzoic acid (CMBA) family. Its mechanism of action is partly similar to that of the sulphonylurea: the release of insulin from the pancreatic beta cells is stimulated by closure of ATP-dependent potassium channels. However, repaglinide regulates these channels via a different binding site on the beta cell than glibenclamide, and the drug does not cause insulin release in the absence of glucose, or during voltage-clamping. After oral administration the drug is rapidly absorbed and eliminated. It is therefore used in a meal-related dosing regimen; repaglinide is taken with each main meal. This meal-related use may give a more physiological mimick of daytime insulin requirement than once-daily or twice-daily use of sulphonylurea. Patients using repaglinide are less likely to develop hypoglycaemic symptoms when they miss or postpone a meal in comparison with patients on glibenclamide treatment. In long-term comparative phase 3 clinical studies it was found that repaglinide is equally effective in maintaining glycaemic control as existing sulphonylurea, but it gives significantly better control of postprandial blood glucose levels. Repaglinide can be used as monotherapy both in obese and non-obese type 2 diabetic patients, and is also very effective in combination with drugs like metformin or thiazolidines. Because of its excretion through liver and bile it is also an attractive drug for diabetic patients with diminished kidney function, especially the elderly diabetic. Although the overall incidence of hypoglycaemia was similar during use of repaglinide and of sulphonylurea, fewer serious hypoglycaemic episodes were observed in repaglinide-treated patients.

Topics: Administration, Oral; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Feeding Behavior; Humans; Hypoglycemia; Hypoglycemic Agents; Intestinal Absorption; Metabolic Clearance Rate; Piperidines

This article reviewed the relevant literature including published clinical trials and reviews on currently available oral hypoglycemic agents. Results showed that the benefits of glycemic control have been established through multiple clinical trials. Long-term control of blood glucose levels in type 1 and type 2 diabetic patients will decrease the incidence and prolong the time until progression of diabetic retinopathy, nephropathy, and neuropathy. Our increased understanding of the pathophysiology behind type 2 diabetes has led to the development of many new agents that are aimed at treating the underlying insulin resistance and relative insulinopenia. The sulfonylureas as a group have been used for many years and act by stimulating insulin secretion. They are useful alone or as combination therapy with insulin or another oral hypoglycemic agent. The biguanides act by decreasing hepatic glucose production and by increasing peripheral insulin sensitivity. The alpha-glucosidase inhibitors act nonsystemically by blocking the metabolism of digested polysaccharides and therefore lowering the amount of carbohydrate absorbed in a meal. Benzoic acid derivatives act in a manner similar to that of sulfonylureas by enhancing pancreatic insulin production. They offer a shorter duration of action, lowering the risk of hypoglycemia. The thiazolidinediones increase peripheral insulin sensitivity and are effective as both monotherapy and combination therapy. Oral hypoglycemic agents, when properly administered, are very effective in controlling type 2 diabetes and preventing long-term complications.

Topics: Carbamates; Chromans; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Metformin; Piperidines; Sulfonylurea Compounds; Thiazoles; Thiazolidinediones; Troglitazone

Current agents for the treatment of Type 2 diabetes mellitus improve the metabolic profile but do not reinstate normality. They also reduce chronic diabetic complications, but they do not eliminate them. Thus, new agents with novel actions are required to complement and extend the capabilities of existing treatments. Insulin resistance and beta-cell failure, which are crucial components in the pathogenesis of Type 2 diabetes, remain the underlying targets for new drugs. Recently introduced agents include a short-acting non-sulphonylurea insulin-releaser, repaglinide, which synchronizes insulin secretion with meal digestion in order to reduce post-prandial hyperglycaemia. The thiazolidinedione drugs, troglitazone, rosiglitazone and pioglitazone represent a new class of agonists for the nuclear receptor peroxisome proliferator-activated receptor-gamma (PPARgamma). PPARgamma increases the transcription of certain insulin-sensitive genes, thereby improving insulin sensitivity. The intestinal lipase inhibitor orlistat and the satiety-inducer sibutramine are new weight-reducing agents that may benefit glycaemic control in obese Type 2 diabetes patients. Several further new insulin-releasing agents, and agents to retard carbohydrate digestion and modify lipid metabolism stand poised to enter the market. The extent to which they will benefit glycaemic control remains to be seen. However, the prospect of permanently arresting or reversing the progressive deterioration of Type 2 diabetes continues to evade therapeutic capture.

Topics: Anti-Obesity Agents; Carbamates; Chromans; Diabetes Mellitus, Type 2; Drug Design; Humans; Hypoglycemic Agents; Insulin Resistance; Piperidines; Sulfonylurea Compounds; Thiazoles; Thiazolidinediones; Troglitazone

Topics: Administration, Oral; Carbamates; Cyclohexanes; Diabetes Mellitus; Dose-Response Relationship, Drug; Glucose; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Nateglinide; Phenylalanine; Piperidines; Receptors, Cytoplasmic and Nuclear; Thiazoles; Thiazolidinediones; Transcription Factors

Repaglinide is a novel insulin secretagogue being developed for the management of type 2 (non-insulin-dependent) diabetes mellitus. It stimulates release of insulin from the pancreatic beta-cell, but appears to bind to a different receptor site from sulphonylureas. Repaglinide lowers fasting and postprandial blood glucose levels in animals, healthy volunteers and patients with type 2 diabetes mellitus. Repaglinide is rapidly absorbed and eliminated, which may allow a relatively fast onset and offset of action. Excretion occurs almost entirely by non-renal mechanisms. In comparative clinical trials in patients with type 2 diabetes mellitus, repaglinide 0.5 to 4 mg twice or 3 times daily before meals provided similar glycaemic control to glibenclamide (glyburide) 2.5 to 15 mg/day. Addition of repaglinide to existing metformin therapy resulted in improved glycaemic control. In contrast with glibenclamide, use of repaglinide allowed patients to miss a meal without apparently increasing the risk of hypoglycaemia.

Topics: Animals; Carbamates; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Glyburide; Humans; Hypoglycemic Agents; Islets of Langerhans; Piperidines; Randomized Controlled Trials as Topic; Stereoisomerism

In older patients with type 2 diabetes, life expectancy and the presence of microvascular complications determine the appropriate intensity of glucose control. The available antidiabetic agents offer many options for achieving glycemic targets, based on the needs of the individual patient. New stimulators of insulin secretion include glimepiride (a sulfonylurea) and repaglinide (a meglitinide). The biguanide metformin is especially useful in obese, insulin-resistant patients. Alpha-glucosidase inhibitors such as acarbose and miglitol act locally in the GI tract to reduce postprandial excursion in glucose levels. The insulin-sensitizing drug troglitazone enhances insulin-mediated glucose disposal. When troglitazone is used, careful monitoring of patients' liver function is required.

Topics: 1-Deoxynojirimycin; Acarbose; Age Factors; Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Glucosamine; Humans; Hypoglycemic Agents; Imino Pyranoses; Metformin; Piperidines; Sulfonylurea Compounds; Trisaccharides

The drugs used to treat diabetes mellitus are diverse and involve several classes. However, these drugs can be roughly separated into hypoglycaemic agents, such as insulin and the sulphonylureas, and antihyperglycaemic agents, such as the biguanides, the alpha-glucosidase inhibitors and troglitazone. Reports of insulin overdose are rare. The major effects of insulin overdose are secondary to the insult to the CNS produced by hypoglycaemia. The mainstay of insulin overdose management is glucose replacement therapy. Sulphonylureas are the most commonly used oral antihyperglycaemic agents in the management of type 2 (non-insulin-dependent; NIDDM) diabetes mellitus. Sulphonylureas primarily cause serum glucose reduction by stimulating the release of preformed insulin from the pancreatic islets. The mainstay of sulphonylurea overdose management is glucose replacement therapy, and in severe cases, reduction of insulin release. In the large majority of patients intravenous glucose supplementation will be sufficient to maintain euglycaemia. Repaglinide, a meglitinide analogue, is a new nonsulphonylurea oral hypoglycaemic agent. In overdose, this drug may produce prolonged hypoglycaemia similar to the sulphonylureas. The primary problem with biguanide overdose is the potential for lactic acidosis. The management of biguanide overdose is largely supportive and directed at correcting the metabolic acidosis along with associated complications. The alpha-glucosidase inhibitors, acarbose, voglibose and miglitol competitively and reversibly inhibit the alpha-glucosidase enzymes (glucoamylase, sucrase, maltase and isomaltase) in the brush border in the small intestine, which delays the hydrolysis of complex carbohydrates. They appear unlikely to produce hypoglycaemia in overdose, but abdominal discomfort and diarrhoea may occur. Troglitazone is the first thiazolidinedione antidiabetic drug available. There are no data on overdose, probably because of its very recent introduction. Overdoses with antidiabetic drugs produce major morbidity, with many cases requiring intensive care medicine and prolonged hospital stays. However, fatalities are rare when treatment is initiated early. The management of the hypoglycaemic drugs (insulin and sulphonylureas) is based primarily on restoring and maintaining euglycaemia via intravenous dextrose supplementation. In the case of the sulphonylureas, reduction of insulin secretion via pharmacological intervention may also be necessary. Wi

Topics: Carbamates; Drug Overdose; Glucose; Humans; Hypoglycemic Agents; Insulin; Piperidines; Sulfonylurea Compounds

The highest demand on insulin secretion occurs in connection with meals. In normal people, following a meal, the insulin secretion increases rapidly, reaching peak concentration in the blood within an hour. The mealtime insulin response in patients with Type 2 diabetes is blunted and delayed, whereas basal levels often remain within the normal range (albeit at elevated fasting glucose levels). Restoration of the insulin secretion pattern at mealtimes (prandial phase)--without stimulating insulin secretion in the 'postabsorptive' phase--is the rationale for the development of 'prandial glucose regulators', drugs that are characterized by a very rapid onset and short duration of action in stimulating insulin secretion. Repaglinide, a carbamoylmethyl benzoic acid (CMBA) derivative is the first such compound, which recently has become available for clinical use. Repaglinide is very rapidly absorbed (t(max) less than 1 hour) with a t1/2 of less than one hour. Furthermore, repaglinide is inactivated in the liver and more than 90% excreted via the bile. The implications of tailoring repaglinide treatment to meals were examined in a study where repaglinide was dosed either morning and evening, or with each main meal (i.e. breakfast, lunch, dinner), with the total daily dose of repaglinide being identical. The mealtime dosing caused a significant improvement in both fasting and 24-hour glucose profiles, as well as a significant decrease in HbA1c. In other studies, repaglinide caused a decrease of 5.8 mmol x l(-1) in peak postprandial glucose levels, and a decrease of 3.1 mmol x l(-1) in fasting levels with a reduction in HbA1c of 1.8% compared with placebo. In comparative studies with either sulphonylurea or metformin, repaglinide caused similar or improved control (i.e. HbA1c, mean glucose levels) and the drug was well tolerated (e.g. reported gastrointestinal side-effects were more than halved when patients were switched from metformin to repaglinide). A hallmark of repaglinide treatment is that this medication follows the eating pattern, and not vice versa. Hence the risk of developing severe hypoglycaemia (BG < or = 2.5 mmol x l(-1)) in connection with flexible lifestyles should be reduced. This concept was examined in a study in which patients well controlled on repaglinide skipped their lunch on one occasion. When a meal (i.e. lunch) was skipped--so was the repaglinide dose, whereas in the comparative group on glibenclamide the recommended morning and evenin

Topics: Administration, Oral; Animals; Blood Glucose; Carbamates; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Eating; Fasting; Humans; Hypoglycemic Agents; Metabolic Clearance Rate; Piperidines; Postprandial Period

Diabetes mellitus is a common disease in older people, with almost 50% of Type 2 diabetic patients being over 60 years of age; despite this, half of older people with frank diabetes are not diagnosed. While insulin resistance is common in older people, large numbers also have impaired insulin secretion. Age, body habitus and physical activity all play a role in the pathogenesis of hyperglycaemia associated with diabetes mellitus. Leptin levels relate to insulin resistance in older people and amylin secretion is associated with delayed return of glucose levels to baseline. Depression, impaired cognitive function, and lack of recognition of thirst and subsequent dehydration are important factors to be taken into account in the management of older diabetic patients, who may also have impaired physical function, an increased rate of injurious falls, and increased prevalence of pressure ulcers, amputations and tuberculosis. Hyperglycaemia can result in a decreased pain threshold and incontinence. Dietary management plays less of a role in older diabetic patients but exercise, with a particular emphasis on balance and stability, is an important component of the management and treatment of older diabetic patients. The use of metformin as a treatment should be avoided in patients over 80 years of age because of declining kidney function. Insulin therapy is an option but as hypoglycaemia is related to advancing age, patients should be monitored carefully for the development of hypoglycaemia. Care providers also play an important role in the management of older people with diabetes mellitus. Glycaemic control can be obtained with minimal side-effects in most older diabetics including those patients in nursing homes.

Topics: Aged; Amyloid; Blood Glucose; Carbamates; Cognition Disorders; Depression; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Insulin Resistance; Islet Amyloid Polypeptide; Male; Piperidines

Topics: Animals; Blood Glucose; Carbamates; Clinical Trials, Phase II as Topic; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Piperidines; Protein Precursors

Two novel oral hypoglycaemic agents, NN623 and A4166, have been developed and are now in phase II clinical trial. Both agents have several common characteristics from sulphonylureas. NN623 is a stereoisomer of derivatives of benzoic acid and A4166 is also a stereoisomer of phenylalanine derivative. The predominant mechanism of the action is thought to be like sulphonylureas. Both NN623 and A4166 occupy, at least partly, a common receptor site with glibenclamide and close the ATP-dependent K+ channel. They are rapidly absorbed from the intestine and are eliminated mainly into the bile. NN623 is about 10 times more potent in hypoglycaemic action than glibenclamide and 100 times more than A4166 in terms of dosage. When 1.0 mg NN623 or 60 mg A4166 was given orally in the post-absorptive state to healthy volunteers, both agents evoked hypoglycaemia by 40 min. The duration of hypoglycaemia after NN623 was longer than after A4166 by about 1 hour. The effect of food on their bioavailability is similar. Food has marked influence on the absorption of both drugs and on their efficacy. When 1 mg of NN623 or 60 mg of A4166 was administered just before the meal, Tmax of NN623 and A4166 was 34 +/- 18 min and 18 +/- 6 min, while T1/2 was 0.64 +/- 0.12 h and 0.98 +/- 0.06 h, respectively. The postprandial rise in plasma glucose was reduced at 45 min and thereafter over 4-h after 1.0 mg NN623 and at 30 min to 90 min after 60 mg A4166. Plasma insulin levels rose more than those after placebo from 30 to 90 min after NN623 and at 20 to 40 min after A4166. Both agents stimulated insulin release much more in the postprandial than in the fasting state. There was no difference in the bioavailability after 5 or 7 days of administration. However, when administered immediately after the meal, the absorption of both drugs was delayed and the rise in plasma absorption was not suppressed until 60 min after the meal. Both fasting and postprandial hyperglycaemia were reduced after 1 to 4 weeks of premeal treatment with 0.5 mg NN623 or 60 mg A4166 in subjects with NIDDM. Plasma glucose levels were decreased over 4 h after NN623 and over 1 h after A4166. The meal-induced insulin response was almost doubled by NN623 over 2 h and 1 h by A4166. There was no difference in the bioavailability after breakfast between the first and last administrations of both drugs. In conclusion, a rapid rise in plasma insulin levels is associated with the suppression of postprandial hyperglycaemia.

Topics: Administration, Oral; Biological Availability; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glyburide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Intestinal Absorption; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Reference Values; Stereoisomerism

Asciminib, a first-in-class BCR-ABL1 inhibitor that works by Specifically Targeting the ABL Myristoyl Pocket (STAMP), is a new treatment option for patients with chronic myeloid leukemia who no longer benefit from currently approved tyrosine kinase inhibitors. In vitro, asciminib reversibly inhibits cytochrome P450 (CYP) 3A4/5, CYP2C9, and CYP2C8. This phase I, open-label, two-stage study in healthy participants evaluated the effect of asciminib (40 mg b.i.d. at steady-state) as a potential perpetrator on single-dose pharmacokinetics of a two-drug cocktail containing midazolam (CYP3A substrate) and warfarin (CYP2C9 substrate) in stage 1 (n = 22), and of repaglinide (CYP2C8 substrate) in stage 2 (n = 25). For midazolam plus asciminib versus midazolam, geometric mean (G

Topics: Carbamates; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP2C9; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Drug Interactions; Healthy Volunteers; Humans; Midazolam; Niacinamide; Piperidines; Pyrazoles; Warfarin

Glycemic variability is a risk factor for total death and cardiovascular events. There are no obvious guidelines for the direct treatment of glycemic variability, but it can be improved with the treatment of postprandial hyperglycemia.. We compared the effect of repaglinide versus the combination of mitiglinide and voglibose, used to improve postprandial hyperglycemia, on glycemic variability in Japanese patients with type 2 diabetes.. We performed an open-label randomized cross-over trial between April 2016 and April 2018. Patients with type 2 diabetes who were admitted to our hospital were enrolled in our study (n = 12). Glycemic variability. was assessed using a continuous glucose monitoring system.. The average glucose level of the repaglinide phase (146.1 ± 20.7 mg/dl) and the combination of mitiglinide and voglibose phase (132.3 ± 19.8 mg/dl) were similar (P = 0.10). The standard division (P = 0.0005), coefficient of variation (P = 0.006), and mean amplitude of glycemic excursion (P = 0.002) of glucose were lower in the combination of mitiglinide and voglibose phase than in the repaglinide phase.. Treatment with the combination of mitiglinide and voglibose might be more effective than repaglinide for the improvement of glycemic variability.

Topics: Blood Glucose; Blood Glucose Self-Monitoring; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Inositol; Isoindoles; Japan; Piperidines

In vivo studies were performed with the novel, selective, non-steroidal mineralocorticoid receptor antagonist finerenone to assess the relevance of inductive and/or inhibitory effects on cytochrome P450 (CYP) enzymes observed in vitro.. CYP isoenzyme-specific substrates were incubated in vitro with finerenone or its metabolites to investigate reversible and irreversible inhibitory as well as inductive potential. Three crossover studies in healthy male volunteers investigated the effects of finerenone (20 mg orally) on the pharmacokinetics of the index substrates midazolam (CYP3A4, n = 30), repaglinide (CYP2C8, n = 28) and warfarin (CYP2C9, n = 24).. Finerenone caused direct inhibitory effects on CYP activities in vitro in the rank order CYP2C8, CYP1A1 > CYP3A4 > CYP2C9 and CYP2C19, but not on other major CYP isoforms. Moreover, irreversible inhibition of CYP3A4 was observed. The major metabolites of finerenone demonstrated minor reversible inhibition of CYP1A1, CYP2C9 and CYP3A4 with no hint of time-dependent inhibition of any CYP isoform. Calculations from in vitro data according to regulatory guidelines suggested likely inhibition of CYP2C8 and CYP3A4 in vivo, whereas this was not the case for CYP1A1, CYP2C9 and CYP2C19. Furthermore, finerenone and three of its metabolites were inducers of CYP3A4 in vitro with predicted weak-to-moderate in vivo relevance. Studies in healthy volunteers, prompted by these results, demonstrated no effect of finerenone on CYP isoenzymes for which in vitro data had indicated potential inhibition or induction.. Administration of finerenone 20 mg once daily confers no risk of clinically relevant drug-drug interactions with substrates of cytochrome P450 enzymes.

Topics: Administration, Oral; Adolescent; Adult; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP2C9; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inducers; Cytochrome P-450 Enzyme Inhibitors; Double-Blind Method; Drug Interactions; Germany; Humans; Isoenzymes; Male; Midazolam; Middle Aged; Mineralocorticoid Receptor Antagonists; Models, Biological; Naphthyridines; Piperidines; Substrate Specificity; Warfarin; Young Adult

Compared with newer prandial anti-diabetes agents, repaglinide and acarbose are unique in being globally available in generic versions, being oral, and being the cheapest of all. The aim of this study was to compare their efficacy when used alone or in combination.. In a randomized, double-blind, prospective study, 358 recently diagnosed type 2 diabetes (T2D) patients, who on a combined therapy with metformin and insulin glargine had a fasting plasma glucose (FGP) of <7.2 mmol/L but a 2-h postprandial plasma glucose (2hPPG) >10 mmol/L, were assigned to three groups of additional treatment with either repaglinide, acarbose, or repaglinide-plus-acarbose for 4 months.. With intention-to-treat analysis, 63% of repaglinide group, 45.4 percent of acarbose group, and 75.7% of repaglinide-plus-acarbose group reached the primary endpoint of 2hPPG < 10 mmol/L while maintaining FPG < 7.2 mmol/L. Treatment adherence rate was 75.6% with repaglinide, 61.4% with acarbose, and 81.3% with repaglinide-plus-acarbose (p = 0.001). Among the groups, weight was significantly lower in acarbose group (p < 0.05). Twenty-one percent of repaglinide patients, 4.9% of acarbose subjects, and 10.3% of repaglinide-plus-acarbose cases reported at least one episode of hypoglycemia (p < 0.005). HbA1C and basal insulin requirement were significantly lower in repaglinide group (p = 0.004, p = 0.0002). Triglycerides were lowest in acarbose group (p = 0.005).. Both acarbose and repaglinide were vastly effective in lowering postprandial hyperglycemia of recently diagnosed T2D. When combined, they were even more efficacious and the disease had a better outcome. Compared with newer peers, these two are particularly useful where and when cost consideration in diabetes treatment is a prime concern.

Topics: Acarbose; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Piperidines; Prospective Studies

Glinides are antidiabetic drugs that enhance the early phase of insulin secretion, but have been considered to be less effective at lowering blood glucose than sulfonylureas. However, glinides show a lower risk of hypoglycemia and a greater effect on postprandial hyperglycemia, and are particularly recommended for use in elderly patients with type 2 diabetes. We investigated the efficacy and safety of repaglinide compared with sulfonylurea for the treatment of elderly patients.. In the present multicenter, prospective, randomized, open-label, controlled trial, 57 elderly lean patients with type 2 diabetes who were being treated with sulfonylureas were studied. They were either switched to repaglinide (Repa group) or continued a sulfonylurea (SU group) for 12 weeks. The primary outcome comprised the change in glycemic control, and among the secondary outcomes was the presence of hypoglycemia and drug compliance.. Although glycated hemoglobin (HbA1c) was not significantly different between the two groups (SU +0.02% vs Repa -0.07%), greater improvements in the glycated albumin (GA) and GA to HbA1c ratio (GA/HbA1c) were observed in the Repa group (ΔGA, SU +0.12% vs Repa -1.15%; ΔGA/HbA1c, SU +0.01 vs Repa -0.13; each P < 0.01) without increasing hypoglycemia. When the Repa group was subdivided according to whether GA improved, the SU dose before switching to repaglinide was significantly smaller and the homeostatic model assessment of β-cell function was significantly higher in the GA improvement subgroup.. Switching from SU to Repa improved GA and GA/HbA1c, and had favorable effects on glucose fluctuation in elderly patients with type 2 diabetes.

Topics: Aged; Aged, 80 and over; Biomarkers; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemia; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Prognosis; Prospective Studies; Sulfonylurea Compounds

Rolapitant is a neurokinin-1 receptor antagonist indicated in combination with other antiemetic agents in adults for the prevention of delayed chemotherapy-induced nausea and vomiting. We evaluated the effects of rolapitant oral on the pharmacokinetics of probe substrates for cytochrome P450 (CYP) 2D6 (dextromethorphan), 2C9 (tolbutamide), 2C19 (omeprazole), 2B6 (efavirenz), and 2C8 (repaglinide) in healthy subjects.. This open-label, multipart, randomized, phase 1 study assessed cohorts of 20-26 healthy subjects administered dextromethorphan, tolbutamide plus omeprazole, efavirenz, or repaglinide with and without single, oral doses of rolapitant. Maximum plasma analyte concentrations (C. Rolapitant significantly increased the systemic exposure of dextromethorphan in terms of C. Inhibition of dextromethorphan by a single oral dose of rolapitant 180 mg is clinically significant and can last at least 7 days. No clinically significant interaction was observed between rolapitant and substrates of CYP2C9, CYP2C19, CYP2B6, or CYP2C8. CYP2D6 substrate drugs with a narrow therapeutic index may require monitoring for adverse reactions if given concomitantly with rolapitant.

Topics: Administration, Oral; Adolescent; Adult; Alkynes; Antiemetics; Benzoxazines; Carbamates; Cyclopropanes; Cytochrome P-450 CYP2B6; Cytochrome P-450 CYP2C19; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP2C9; Cytochrome P-450 CYP2D6; Dextromethorphan; Drug Combinations; Drug Interactions; Female; Healthy Volunteers; Humans; Male; Middle Aged; Molecular Probes; Neurokinin-1 Receptor Antagonists; Omeprazole; Piperidines; Spiro Compounds; Tolbutamide; Young Adult

Evocalcet is a novel calcimimetic agent for the treatment of secondary hyperparathyroidism (SHPT). This study evaluated the effects of evocalcet on inhibition and induction of cytochrome P450 (CYP) isozymes. Although drug interactions arising from reversible inhibition of CYP isozymes by evocalcet were considered unlikely based on the results of in vitro studies and static model analyses, the potential for evocalcet to cause time-dependent inhibition of CYP3A or induction of several CYP isozymes could not be ruled out. Therefore, a clinical drug-drug interaction (DDI) study to evaluate the effects of evocalcet on the pharmacokinetics (PKs) of probe substrates for CYP isozymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, and CYP3A) was conducted in healthy male volunteers using a novel cocktail combination. Evocalcet did not significantly affect the PKs of the probe substrates, confirming that CYP-mediated interactions were unlikely.

Topics: Administration, Oral; Adult; Alkynes; Benzoxazines; Calcimimetic Agents; Carbamates; Cells, Cultured; Cyclopropanes; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drug Interactions; Healthy Volunteers; Hepatocytes; Humans; Hyperparathyroidism, Secondary; Inhibitory Concentration 50; Isoenzymes; Male; Naphthalenes; Oxidation-Reduction; Piperidines; Primary Cell Culture; Pyrrolidines; Theophylline; Young Adult

As survival among patients with cystic fibrosis has improved in recent decades, complications have become increasingly relevant. The most frequent complication is cystic-fibrosis-related diabetes. The recommended treatment is injected insulin, but some patients are treated with oral antidiabetic drugs to ease the treatment burden. We assessed the efficacy and safety of oral antidiabetic drugs.. We did a multicentre, open-label, comparative, randomised trial in 49 centres in Austria, France, Germany, and Italy. Eligible patients had cystic fibrosis, were older than 10 years, and had newly diagnosed diabetes. We used a central randomisation schedule derived from a Geigy random number table to assign patients 1:1 to receive insulin or repaglinide, stratified by sex and age (10-15 years or >15 years). The primary outcome was glycaemic control assessed by mean change in HbA. Repaglinide for glycaemic control in patients with cystic-fibrosis-related diabetes is as efficacious and safe as insulin.. Mukoviszidose eV, Vaincre la Mucoviscidose, ABCF Association, and Novo Nordisk.

Topics: Adolescent; Adult; Biomarkers; Blood Glucose; Carbamates; Child; Cystic Fibrosis; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Male; Piperidines; Prognosis; Young Adult

This study was conducted to determine whether a fixed-dose combination (FDC) tablet of repaglinide/metformin (2/500 mg) is equivalent to coadministration of equivalent doses of individual (EDI) tablets of repaglinide (2 mg) and metformin (500 mg) in healthy Korean male subjects.. This study was conducted as an open-label, randomized, single-dose, two-period, two-sequence crossover design in 50 healthy Korean male subjects who received an FDC tablet or EDI tablets. Plasma concentrations of repaglinide and metformin were determined for up to 24 hours using a validated UPLC-MS/MS method. Bioequivalence was assessed according to current guidelines issued by the U.S. Food and Drug Administration (FDA) and Korean legislation. Tolerability was also evaluated throughout the study via subject interview, vital signs, and blood sampling.. Point estimates (90% CIs) for AUC. Results of pharmacokinetic analysis suggested that repaglinide and metformin in FDC tablets were bioequivalent to EDI tablets of repaglinide (2 mg) and metformin (500 mg) in healthy Korean male subjects. Both formulations appeared to be well tolerated.
.

Topics: Adult; Carbamates; Cross-Over Studies; Drug Combinations; Drug Therapy, Combination; Humans; Male; Metformin; Piperidines; Tablets; Therapeutic Equivalency

Post-Market Research We aimed to investigate the impact of G protein-coupled receptor kinase 5 (GRK5) rs10886471 polymorphism on repaglinide efficacy in Chinese patients with type 2 diabetes mellitus (T2DM). A total of 300 T2DM patients and 210 healthy controls were genotyped for GRK5 rs10886471 on a three-dimensional polyacrylamide gel-based DNA microarray. Eighty-five patients with the same genotypes of cytochrome P450 (CYP) 2C8*3 139Arg and organic anion-transporting polypeptide 1B1 (OATP1B1) 521TT were randomly selected to orally take repaglinide for eight consecutive weeks. Then, the biochemical indicators and pharmacodynamic parameters were measured before and after repaglinide treatment. The T allelic frequency of GRK5 rs10886471 was higher in T2DM patients than in healthy subjects (p < .01). T2DM patients with genotypes CC and CT at GRK5 rs10886471 had a significant reduction in terms of fasting plasma glucose (FPG) compared with those with genotype TT (p < .01). In addition, the carriers of genotypes CC and CT at GRK5 rs10886471 had higher differential values of postprandial serum insulin (PINS) compared with genotype TT carriers (p < .05). These findings suggest that GRK5 rs10886471 polymorphism may influence the therapeutic efficacy of repaglinide in Chinese Han T2DM patients.

Topics: Asian People; Blood Glucose; Carbamates; Cytochrome P-450 CYP2C8; Diabetes Mellitus, Type 2; Female; G-Protein-Coupled Receptor Kinase 5; Genotype; Humans; Hypoglycemic Agents; Insulin; Liver-Specific Organic Anion Transporter 1; Male; Middle Aged; Piperidines; Polymorphism, Genetic; Treatment Outcome

This study aims to compare the effect of repaglinide and metformin among Chinese patients with newly diagnosed diabetes, and explore the possible mechanisms by which repaglinide alters insulin secretion.Sixty subjects with glycated hemoglobin (HbA1c) < 10.0% were randomly selected to receive repaglinide or metformin monotherapy for 15 weeks. Blood glucose levels, glycemic variability, β-cell function, and first-phase insulin secretion were compared between these 2 groups at baseline and at 15 weeks. Mouse insulinoma (MIN-6) cells were divided into 3 groups: low glucose, high glucose, and repaglinide 50 nm groups. Cells and cell culture mediums were collected at different timepoints. The expression of pericentrin (PCNT), F-actin, and insulin were tested with immunofluorescence and enzyme-linked immunosorbent assay.All glycemic parameters and variability indexes significantly decreased from baseline to 15 weeks, while no significant difference was found between these 2 groups at baseline or at 15 weeks. Furthermore, there was no significant difference found in fasting insulin and postprandial insulin at baseline and at 15 weeks, while homeostasis model assessment β significantly increased. The first-phase glucose and insulin secretion of the intravenous glucose tolerance test improved in both groups, especially in the repaglinide group. Insulin, PCNT, and F-actin expression in MIN-6 cells decreased after 15 minutes of stimulation with repaglinide, while no difference was observed at 2, 6, and 12 hours. The insulin levels of the cell medium in the repaglinide group remained significantly higher at all timepoints.This study manifests that repaglinide has a noninferiority effect on the glycemic parameters of Chinese patients with newly diagnosed diabetes, when compared with metformin. The PCNT-F-actin pathway plays an important role in the repaglinide regulation process of on-demand insulin secretion.

Topics: Actins; Adult; Aged; Aged, 80 and over; Antigens; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Middle Aged; Piperidines; Treatment Outcome; Young Adult

This report describes phase 1 clinical trials performed to assess interactions of oral isavuconazole at the clinically targeted dose (200 mg, administered as isavuconazonium sulfate 372 mg, 3 times a day for 2 days; 200 mg once daily [QD] thereafter) with single oral doses of the cytochrome P450 (CYP) substrates: bupropion hydrochloride (CYP2B6; 100 mg; n = 24), repaglinide (CYP2C8/CYP3A4; 0.5 mg; n = 24), caffeine (CYP1A2; 200 mg; n = 24), dextromethorphan hydrobromide (CYP2D6/CYP3A4; 30 mg; n = 24), and methadone (CYP2B6/CYP2C19/CYP3A4; 10 mg; n = 23). Compared with each drug alone, coadministration with isavuconazole changed the area under the concentration-time curves (AUC

Topics: Adult; Area Under Curve; Bupropion; Caffeine; Carbamates; Cytochrome P-450 Enzyme System; Dextromethorphan; Drug Interactions; Female; Healthy Volunteers; Humans; Male; Methadone; Middle Aged; Nitriles; Piperidines; Pyridines; Triazoles; Young Adult

Despite the current guideline's recommendation of a timely stepwise intensification therapy, the "clinical inertia", termed as the delayed treatment intensification, commonly exists in the real world, which may be partly due to the relatively little substantial evidence and no clear consensus regarding the efficacy and safety of triple oral agents in patients inadequately controlled with dual therapy. In this clinical trial performed in 237 centers in China, 5,535 type 2 diabetic patients inadequately controlled by previous therapies were treated with a stable metformin/sitagliptin dual therapy for 20 weeks. The patients who did not reach the glycated hemoglobin A1c (HbA1c) goal were then further randomized into glimepiride, gliclazide, repaglinide, or acarbose group for an additional 24-week triple therapy. A mean HbA1c reduction of 0.85% was observed when sitagliptin was added to the patients inadequately controlled with metformin in 16 weeks. Further HbA1c reductions in the 24-week triple therapy stage were 0.65% in glimepiride group, 0.70% in gliclazide group, 0.61% in repaglinide group, and 0.45% in acarbose group. The non-inferiority criterion for primary hypotheses was met for gliclazide and repaglinide, but not for acarbose, compared with glimepiride, when added to metformin/sitagliptin dual therapy. The incidences of adverse events (AEs) were 29.2% in the dual therapy stage and 30.3% in the triple therapy stage. Metformin/sitagliptin as baseline therapy, with the addition of a third oral antihyperglycemic agent, including glimepiride, gliclazide, repaglinide, or acarbose, was effective, safe and well-tolerated for achieving an HbA1c <7.0% goal in type 2 diabetic patients inadequately controlled with previous therapies. The timely augmentation of up to three oral antihyperglycemic agents is valid and of important clinical benefit to prevent patients from exposure to unnecessarily prolonged hyperglycemia.

Topics: Acarbose; Adult; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Gliclazide; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Sitagliptin Phosphate; Sulfonylurea Compounds; Treatment Outcome

Objective Switching from sulfonylureas to repaglinide in patients with type 2 diabetes improves glycemic control; however, the optimal dosage has not been fully evaluated. We designed to show that repaglinide was equivalent to sulfonylurea in Japanese patients with type 2 diabetes. We herein evaluated whether we could switch from sulfonylureas to repaglinide twice or thrice daily in Japanese adult patients who had been treated with anti-diabetic drugs, including sulfonylureas, and whose conditions were moderately well-controlled. Methods A total of 78 patients taking less than half the Japanese maximum dose of sulfonylurea were randomized into three groups: 26 in group A (switching from sulfonylureas to taking 0.25 or 0.5 mg of repaglinide just before breakfast and dinner twice daily), 27 in group B (switching from sulfonylureas to taking 0.25 or 0.5 mg of repaglinide just before meals thrice daily), and 25 in group C (continuing to take sulfonylurea). Blood samples were collected at 0, 1, 2, 3, and 4 months following the initiation of the maintenance period. Results The HbA1c and glycoalbumin levels did not significantly differ among the three groups after 4 months of treatment. Conclusion With the assumption that 1 mg of glimepiride is equivalent to 1.25 mg of glibenclamide or 40 mg of gliclazide, the administration of repaglinide (0.44 mg/meal) twice and thrice daily is similar to the efficacy of sulfonylurea (glimepiride 1.63-1.98 mg/day) after four months of treatment in Japanese patients with moderately well-controlled type 2 diabetes (HbA1c, 7-7.5%).

Topics: Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Female; Glycated Hemoglobin; Glycated Serum Albumin; Glycation End Products, Advanced; Humans; Hypoglycemic Agents; Japan; Male; Middle Aged; Piperidines; Serum Albumin; Sulfonylurea Compounds

Although sitagliptin and repaglinide monotherapies improve postprandial hyperglycemia, the long-term effects and safety of their combination has not been examined. In this randomized 24-week trial of Japanese patients with poor control (HbA1c 7.0-8.5%) by sitagliptin, we divided 40 patients randomly into two equal groups of the repaglinide add-on to sitagliptin (ADD-ON, n=20), or sitagliptin switched to repaglinide (SWITCH, n=20). The meal tolerance test was carried out at weeks 0 and 24. The primary outcomes were changes in HbA1c and area under the curves (AUC) of glucose from the baseline to week 24. The mean change in HbA1c from baseline to week 24 was larger in the ADD-ON (-0.87±0.63%, mean±SD), compared with the SWITCH (0.03±0.65%, p=0.000). Significant improvements were noted in the mean changes in fasting glucose and AUCs of glucose in the ADD-ON vs. SWITCH (p=0.007 and p=0.000). Insulin secretion relative to glucose elevation (ISG; defined as AUC insulin/AUC glucose) increased significantly in the ADD-ON, although the mean change in fasting insulin level was significantly decreased in the ADD-ON (p=0.015 and p=0.026). The AUC of glucagon was significantly lower at 24-week relative to baseline in the ADD-ON, but was not significant in the two groups (p=0.047 and p=0.056, respectively). The combination therapy produced significant reductions in HbA1c, AUC of glucose and fasting glucose compared with switching to repaglinide without weight gain or severe hypoglycemia. The improved glycemic control with this combination therapy may be at least in part due to augmentation of repaglinide-induced insulin secretion by sitagliptin.

Topics: Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Substitution; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Middle Aged; Piperidines; Postprandial Period; Sitagliptin Phosphate; Treatment Outcome

Repaglinide is an insulin secretagogue that often exhibits considerable interindividual variability in therapeutic efficacy. The current study was designed to investigate the impact of KCNQ1 genetic polymorphism on the efficacy of repaglinide and furthermore to identify the potential mechanism of action in patients with type 2 diabetes. A total of 305 patients and 200 healthy subjects were genotyped for the KCNQ1 rs2237892 polymorphism, and 82 patients with T2DM were randomized for the oral administration of repaglinide for 8 weeks. HepG2 cells were incubated with repaglinide in the absence or presence of a KCNQ1 inhibitor or the pcDNA3.1-hKCNQ1 plasmid, after which the levels of Akt, IRS-2 and PI(3)K were determined. Our data showed that repaglinide significantly decreased HOMA-IR in patients with T2DM. Furthermore, the level of HOMA-IR was significantly reduced in those patients with CT or TT genotypes than CC homozygotes. The KCNQ1 inhibitor enhanced repaglinide efficacy on insulin resistance, with IRS-2/PI(3)K/Akt signaling being up-regulated markedly. As in our clinical experiment, these data strongly suggest that KCNQ1 genetic polymorphism influences repaglinide response due to the pivotal role of KCNQ1 in regulating insulin resistance through the IRS-2/PI(3)K/Akt signaling pathway. This study was registered in the Chinese Clinical Trial Register on May 14, 2013. (No. ChiCTR-CCC13003536).

Topics: Adult; Asian People; Carbamates; China; Diabetes Mellitus, Type 2; Female; Hep G2 Cells; Humans; Insulin Receptor Substrate Proteins; Insulin Resistance; KCNQ1 Potassium Channel; Male; Middle Aged; Phosphatidylinositol 3-Kinases; Piperidines; Polymorphism, Genetic; Proto-Oncogene Proteins c-akt; Signal Transduction

Repaglinide is a short-acting insulin secretagogue, which often results in considerable interindividual variability in therapeutic efficacy when widely used in a clinical setting. Among various reasons under discussion is genetic polymorphism, especially the genes related to insulin secretion and resistance. Recent studies have described the importance of PPARD in regulating the secretion and resistance of insulin. However, little is known about the impacts of PPARD genetic polymorphism on the efficacy of repaglinide. Therefore, the current study was designed to investigate the associations of PPARD rs2016520 polymorphism with type 2 diabetes mellitus (T2DM) susceptibility and repaglinide therapeutic efficacy in Chinese Han T2DM patients. A total of 338 T2DM patients and 200 healthy subjects were genotyped for PPARD rs2016520 polymorphism by polymerase chain reaction-restriction fragment length polymorphism assay. A total of 84 patients with the same genotypes of CYP2C8*3 139Arg and OATP1B1 521TT were randomized to orally take repaglinide for 8 weeks. Then the pharmacodynamic parameters of repaglinide and biochemical indicators were determined before and after repaglinide treatment. No significant difference was found in either allelic frequency (P = 0.298) or genotype distribution (P = 0.151) of PPARD rs2016520 between T2DM patients and healthy subjects. However, T2DM patients carrying genotype TC showed a significantly lower increase in postprandial serum insulin (mU/L) than those with wild-type TT (P < 0.05). These findings suggest that PPARD rs2016520 polymorphism might influence the therapeutic effect of repaglinide rather than T2DM susceptibility in Chinese Han T2DM patients.

Topics: Adult; Asian People; Carbamates; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Piperidines; Polymorphism, Genetic; Postprandial Period; PPAR delta; Treatment Outcome

A combination therapy of metformin hydrochloride (MH) and repaglinide (RG) achieves a perfect glycemic control; however, the combination formulation of immediate release must be taken several times a day, compromising the therapeutic benefits and causing inconveniences to the patients. Herein, a bilayer matrix tablet that aimed at continuously releasing both MH and RG over time was developed, in which the two drugs were formulated into two separated layers. The tablets were prepared by wet granulation method, and the optimized formulation was obtained by evaluating the factors that affected the drug release. The bilayer tablets simultaneously released the two drugs over 12 h; and a better in vivo performance with a steady plasma concentration, markedly lower Cmax, prolonged Tmax, and perfect absorption was obtained. Summarily, the bilayer matrix tablets sustained both MH and RG release over time, thereby prolonging the actions for diabetic therapy and producing better health outcomes.

Topics: Animals; Carbamates; Chemistry, Pharmaceutical; Cross-Over Studies; Delayed-Action Preparations; Dogs; Drug Combinations; Male; Metformin; Piperidines; Tablets

Repaglinide and pioglitazone are both CYP2C8 and CYP3A4 substrates. This study was to determine whether repaglinide has an inhibitory effect on the metabolism of pioglitazone in vitro, in silico and in vivo.. In vitro, the effect of repaglinide on the metabolism of pioglitazone was assessed in pooled human liver microsomes. In silico, an IVIVE-PBPK linked model was built with Simcyp®. Then, a randomized, 2-phase cross-over clinical study was conducted in 12 healthy volunteers.. Repaglinide showed a strong inhibitory effect on the metabolism of pioglitazone in vitro (Ki  = 0.0757 µm), [I]/Ki  > 0.1. The Simcyp® prediction ratios of AUC and Cmax between the two treatment groups were both about 1.01. The pharmacokinetics of pioglitazone in clinical trials showed no significant difference between these two treatment groups (p > 0.05).. Repaglinide has no significant inhibitory effect on the metabolism of pioglitazone in vivo, which is inconsistent with the in vitro results. The lack of an inhibitory effect was partly due to extensive plasma protein binding and to the high in vivo clearance of repaglinide, for the concentration of repaglinide in vivo was far smaller than in vitro.

Topics: Adolescent; Adult; Algorithms; Biotransformation; Carbamates; Chemical Phenomena; Computational Biology; Cross-Over Studies; Drug Interactions; Expert Systems; Half-Life; Humans; Hypoglycemic Agents; Metabolic Clearance Rate; Microsomes, Liver; Middle Aged; Models, Biological; Pioglitazone; Piperidines; Software; Thiazolidinediones; Young Adult

To investigate the associations of NOS1AP rs12742393 polymorphism with the risk of type 2 diabetes mellitus (T2DM) and repaglinide therapeutic efficacy in Chinese patients with T2DM.. Prospective case-control study.. Academic medical center.. A total of 300 patients with T2DM and 200 healthy volunteers were enrolled to identify NOS1AP rs12742393 genotypes using the polymerase chain reaction-restriction fragment length polymorphism assay. Eighty-four patients with various genotypes were randomly selected to receive oral repaglinide as a single-agent therapy (3 mg/day) for 8 weeks.. Anthropometric measurements and fasting plasma glucose (FPG), postprandial plasma glucose, hemoglobin A1c , fasting serum insulin (FINS), postprandial serum insulin, homeostasis model assessment for insulin resistance (HOMA-IR), triglyceride, total cholesterol, low-density lipoprotein-cholesterol, and high-density lipoprotein-cholesterol tests were obtained before and after repaglinide treatment. The risk C allelic frequency of NOS1AP rs12742393 was higher in patients with T2DM than in healthy volunteers (p<0.001). Patients with T2DM and genotypes AA and AC at NOS1AP rs12742393 had a significant reduction in FPG (mmol/l) compared with those with genotype CC (p<0.01). Patients with CC homozygotes and AC heterozygotes had a greater increase in FINS (mU/l) than those with wild-type AA (p<0.05). In addition, the carriers of genotype CC at NOS1AP rs12742393 had higher differential values of HOMA-IR compared with genotypes AC and AA carriers (p<0.001). The effects of repaglinide treatment on FPG (p<0.01), FINS (p<0.05) and HOMA-IR (p<0.001) were reduced in patients with T2DM carrying the NOS1AP rs12742393 risk C allele compared with the AA genotype carriers.. The NOS1AP rs12742393 polymorphism is associated with therapeutic efficacy of repaglinide in Chinese T2DM patients.

Topics: Adaptor Proteins, Signal Transducing; Adult; Alleles; Asian People; Blood Glucose; Carbamates; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Gene Frequency; Genotype; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Polymerase Chain Reaction; Polymorphism, Genetic; Polymorphism, Restriction Fragment Length; Prospective Studies

Diabetes mellitus may be present in patients with cystic fibrosis starting in the second decade of life. The prevalence increases rapidly with increasing age. As life-expectancy increases in cystic fibrosis, cystic fibrosis related diabetes will be diagnosed more frequently in the future.Up to date, no data are available to answer the question if cystic fibrosis related diabetes should always initially be treated by insulin therapy. Missing data regarding oral antidiabetic treatment of newly diagnosed cystic fibrosis related diabetes are an important reason to recommend insulin treatment. Several centres report the successful management of cystic fibrosis related diabetes using oral anti-diabetic drugs at least for some years. Oral therapies would be less invasive for a patient group which is highly traumatized by a very demanding therapy. Based on an initiative of the German Mukoviszidosis-Foundation, the present study tries to answer the question, whether oral therapy with repaglinide is as effective as insulin therapy in cystic fibrosis patients with early diagnosed diabetes mellitus.. In all cystic fibrosis patients with an age of 10 years or older, an oral glucose tolerance test is recommended. The result of this test is classified according to the WHO cut off values. It is required to have two diabetes positive oral glucose tolerance tests for the diagnosis of diabetes mellitus.This study is a multi-national, multicentre, open labelled, randomized and prospective controlled parallel group's trial, with 24 months treatment.The primary objective of this trial is to compare the glycaemic control of oral therapy with Repaglinide with insulin injections in patients with cystic fibrosis related diabetes after 2 years of treatment.The trial should include 74 subjects showing cystic fibrosis related diabetes newly diagnosed by oral glucose tolerance test during annual screening for cystic fibrosis related diabetes.Patients are randomised by central fax randomisation.Primary endpoint is mean HbA1c after 24 months of treatment. Secondary endpoints are change in FEV1% predicted and change in BMI-Z-score.. There is only one prospective study comparing oral antidiabetic drugs to insulin in the treatment of CFRD without fasting hyperglycaemia. The results regarding BMI after 6 months and 12 months showed an improvement for the insulin treated patients and were inconsistent for those treated with repaglinide. HbA1c and lung function (FEV1%pred) were unchanged for either group. The authors compared the changes -12 months to baseline and baseline to +12 months separately for each group. Therefore a direct comparison of the effect of repaglinide versus insulin on BMI, HbA1c and FEV1%pred was not presented. According to our protocol, we will directly compare treatment effects (HbA1c, BMI, FEV1%pred) in between both groups. The actual Cochrane report regarding "Insulin and oral agents for managing CFRD" stated that further studies are needed to establish whether there is clear benefit for hypoglycemic agents. We expect that the results of our study will help to address this clinical need.. ClinicalTrials.gov Identifier: NCT00662714.

Topics: Adolescent; Algorithms; Carbamates; Child; Cystic Fibrosis; Diabetes Mellitus; Early Diagnosis; Humans; Hypoglycemic Agents; Insulin; Piperidines; Prospective Studies

We aimed to compare the effect of repaglinide and metformin monotherapy as an initial therapy in Chinese patients with newly diagnosed type 2 diabetes mellitus (T2DM).. In this 15-week, open-labelled, parallel-controlled, randomised study, 60 Chinese drug-naive patients with newly diagnosed T2DM were randomised (2:1) to receive repaglinide or metformin monotherapy. Primary endpoint was change in HbA1c from baseline to the end of the trial. Secondary endpoints included changes in glycaemic variability, insulin sensitivity and β-cell function.. Patients in both repaglinide and metformin groups achieved significant reductions in HbA1c (-1.8 ± 1.5 vs -1.6 ± 1.5%), FPG (fasting blood glucose) (-1.7 ± 1.7 vs -2.1 ± 1.7  mmol/l) and 2-h PPG (post-prandial glucose) (-3.8 ± 3.1 vs -3.8 ± 3.6  mmol/l), with no statistical differences between the groups. Glycaemic variability, glucose infusion rate and β-cell function were all significantly improved from baseline in the two groups (all P<0.05), without any statistical differences in the improvement between the groups.. Repaglinide and metformin achieved comparable efficacy in improving glycaemic control, reducing glycaemic variability, enhancing insulin sensitivity and ameliorating β-cell function. Therefore, repaglinide is an optional agent for initial therapy in Chinese patients with newly diagnosed T2DM.

Topics: Adult; Aged; Aged, 80 and over; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Female; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Young Adult

This study was designed to compare the effects of metformin and repaglinide on the fasting plasma glucose (FPG) and glycated haemoglobin (HbA1c) in newly diagnosed type 2 diabetes in China.. A total of 107 newly diagnosed type 2 diabetic patients (46 women and 61 men) participated in the study. All patients received 3-month treatment of metformin or repaglinide. Fasting blood glucose and HbA1c were determined at baseline and at the end of the 3-month of treatment.. FPG and HbA1c decreased in both metformin and repaglinide groups after 3 months treatment (P < 0.01). The reduction of HbA1c was significantly greater in the repaglinide group (P < 0.01). Metformin decreases fasting insulin concentration and HOMA-IR (P < 0.01), and repaglinide improves HOMA-β(P < 0.01). Triglycerides (TG) were reduced in both groups (P < 0.01 in metformin group; P < 0.05 in repaglinide group), but total cholesterol (TC) and low-density lipoprotein (LDL) were decreased only after metformin treatment (P < 0.05).. Both repaglinide and metformin were effective in glycaemic control in new onset patients with type 2 diabetes in China. Repaglinide had no effect on insulin sensitivity, but it improved β-cell function.

Topics: Body Mass Index; Carbamates; China; Combined Modality Therapy; Diabetes Mellitus, Type 2; Diet, Diabetic; Diet, Reducing; Drug Monitoring; Female; Glycated Hemoglobin; Humans; Hyperglycemia; Hyperlipidemias; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Metformin; Middle Aged; Overweight; Piperidines; Weight Loss

Cerivastatin and repaglinide are substrates of cytochrome P450 (CYP)2C8, CYP3A4, and organic anion-transporting polypeptide (OATP)1B1. A recent study revealed an increased risk of rhabdomyolysis in patients using cerivastatin with clopidogrel, warranting further studies on clopidogrel interactions. In healthy volunteers, repaglinide area under the concentration-time curve (AUC(0-∞)) was increased 5.1-fold by a 300-mg loading dose of clopidogrel and 3.9-fold by continued administration of 75 mg clopidogrel daily. In vitro, we identified clopidogrel acyl-β-D-glucuronide as a potent time-dependent inhibitor of CYP2C8. A physiologically based pharmacokinetic model indicated that inactivation of CYP2C8 by clopidogrel acyl-β-D-glucuronide leads to uninterrupted 60-85% inhibition of CYP2C8 during daily clopidogrel treatment. Computational modeling resulted in docking of clopidogrel acyl-β-D-glucuronide at the CYP2C8 active site with its thiophene moiety close to heme. The results indicate that clopidogrel is a strong CYP2C8 inhibitor via its acyl-β-D-glucuronide and imply that glucuronide metabolites should be considered potential inhibitors of CYP enzymes.

Topics: Aryl Hydrocarbon Hydroxylases; Carbamates; Catalytic Domain; Clopidogrel; Computer Simulation; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Drug Interactions; Female; Glucuronides; Humans; Hypoglycemic Agents; Male; Metabolic Detoxication, Phase II; Molecular Docking Simulation; Piperidines; Platelet Aggregation Inhibitors; Ticlopidine; Time Factors

To compare the efficacy, safety and compliance of repaglinide, administered either two or three times daily, regarding glycaemic control in patients with type 2 diabetes mellitus.. Japanese adults with type 2 diabetes mellitus, who had been treated without sulphonylureas or glinides for >3 months, were randomly assigned to two groups to receive either 0.25 mg repaglinide, oral, twice daily (group A) or 0.25 mg repaglinide, oral, three times daily (group B). Glycosylated haemoglobin (HbA1c), glycoalbumin (GA) and 1,5-anhydroglucitol (1,5-AG) levels were measured at 0, 1, 2 and 3 months after treatment commenced.. Out of 43 patients who enrolled (group A, n = 22; group B, n = 21), 33 patients completed the trial (group A, n = 16; group B, n = 17). No significant between-group differences in HbA1c, GA, or 1,5-AG levels were seen at 1-3 months. No severe hypoglycaemic episodes or other adverse events were observed.. Minimal-dose repaglinide administered twice daily was similar in efficacy and safety to three-times-daily administration, in Japanese patients with type 2 diabetes mellitus. Administration of repaglinide twice daily could be an alternative regimen for patients who cannot take repaglinide three times daily.

Topics: Administration, Oral; Adult; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Female; Follow-Up Studies; Glycated Hemoglobin; Glycemic Index; Humans; Hypoglycemic Agents; Japan; Male; Middle Aged; Piperidines; Prognosis

Patients with type 2 diabetes are at increased susceptibility to a prolonged QT interval. Furthermore, insulin secretagogues, drugs used to treat diabetes, may prolong QT interval and provoke arrhythmias. We evaluated whether secretagogues can affect QTc interval during cardiac stress test in 20 patients with type 2 diabetes treated with secretagogues. ECG stress test was performed in all patients. QTc interval was calculated both before cardiac stress test (BCST) and at acme of cardiac stress test (ACST). Diabetic patients treated with secretagogues showed longer QTc-ACST values than those treated with metformin only. QTc-ACST values resulted shorter than QTc-BCST values in control group. Diabetic patients treated with secretagogues showed QTc-ACST values significantly longer than QTc-BCST values. In our study, diabetic patients treated with secretagogues did not show the QTc physiologic decrease that is a protective against arrhythmias. These results suggest to evaluate, in these patients, QT length, even during routine cardiac stress test.

Topics: Aged; Arrhythmias, Cardiac; Carbamates; Diabetes Mellitus, Type 2; Electrocardiography; Exercise Test; Female; Glyburide; Heart Rate; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines

The effect of pitavastatin and SLCO1B1 genetic background on the pharmacokinetic and pharmacodynamic properties of repaglinide was investigated. In this randomized, placebo-controlled, crossover study, twelve healthy Chinese males were administered with pitavastatin 4 mg/d or the placebo for 5 d followed by repaglinide 4 mg given orally on d 5. Plasma repaglinide and glucose levels were measured by liquid chromatography-tandem mass spectrometry (LC/MS/MS) and the glucose oxidase method, respectively. Treatment with pitavastatin significantly increased the peak plasma concentration (Cmax) of repaglinide (P=0.003) in SLCO1B1*1b homozygotes (P=0.015) and SLCO1B1*15 carriers (P=0.031). Treatment with pitavastatin led to a marginal increase in the area under plasma concentration-time curve from 0 h to infinity (AUC0⇒∞) of repaglinide (P=0.091). There was no significant difference in pharmacokinetic parameters or hypoglycemic effects of repaglinide among SLCO1B1 genotypes in either the pitavastatin or control group. Pitavastatin increased the Cmax of the plasma concentration of repaglinide in an SLCO1B1 genotype dependent manner, but had no apparent effect on the pharmacodynamics of repaglinide in healthy volunteers. The p values for this statement were not reported.

Topics: Area Under Curve; Asian People; Blood Glucose; Carbamates; Cross-Over Studies; Drug Interactions; Genotype; Homozygote; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Male; Organic Anion Transporters; Piperidines; Polymorphism, Single Nucleotide; Quinolines

CYP3A4 is the main isoform of cytochrome P450 oxidases involved in the metabolism of approximately 60 % drugs, and its expression level is highly variable in human subjects. CYP3A4 is regulated by many transcription factors, among which the pregnane X receptor/steroid and xenobiotic receptor (PXR/SXR, NR1I2) have been identified as the most critical. Genetic polymorphisms (such as SNPs) in PXR may affect the expression level of CYP3A4. Although numerous SNPs have been identified in PXR and have appeared to affect PXR function, their impact on the expression of CYP3A4 in human subjects has not been well studied. Thus, a clinical study in healthy Chinese subjects was conducted to investigate the impact of PXR polymorphisms on repaglinide (an endogenous marker for CYP3A4 activity) pharmacokinetics used alone or in combination with a PXR inducer, flucloxacillin.. Two SNPs, -298A>G and 11193T>C, were identified as the tag SNPs to represent the overall genetic polymorphic profile of PXR. To evaluate the potential functional change of these two SNPs, 24 healthy subjects were recruited in a pharmacokinetics/pharmacodynamics study of repaglinide with or without flucloxacillin.. The pharmacokinetic parameters including AUC and T1/2 were significantly different among the PXR genotype groups. The SNPs of -298G/G and 11193C/C were found to be associated with a lower PXR activity resulting in reduction of CYP3A4 activity in vivo. After administration of flucloxacillin, a significant drug-drug interaction was observed. The clearance of repagnilide was significantly increased by concomitant flucloxacillin in a genotype dependent manner. The subjects with SNPs of -298G/G and 11193C/C appeared to be less sensitive to flucloxacillin.. Our study results demonstrated for the first time the impact of genetic polymorphisms of PXR on the PK and PD of repaglinide, and showed that subjects with genotype of -298G/G and 11193C/C in PXR has a decreased elimination rate of 3A4/2C8. Furthermore, flucloxacillin was able to induce 3A4/2C8 expression mediated by PXR in a genotype dependent manner.

Topics: Anti-Bacterial Agents; Aryl Hydrocarbon Hydroxylases; Asian People; Blood Glucose; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Drug Interactions; Floxacillin; Genotype; Healthy Volunteers; Humans; Hypoglycemic Agents; Piperidines; Polymorphism, Single Nucleotide; Pregnane X Receptor; Receptors, Steroid

We aimed to determine whether NeuroD1/BETA2 and PAX4 polymorphisms were associated with the therapeutic efficacy of repaglinide in Chinese type 2 diabetes mellitus (T2DM) patients.. Three hundred and sixty-eight T2DM patients and 132 healthy control subjects were genotyped by restriction fragment length polymorphism. Forty-three patients with various genotypes were randomly selected to undergo 8 weeks of repaglinide treatment (3 mg day(-1)). Fasting plasma glucose, postprandial plasma glucose, glycated haemoglobin, fasting and postprandial serum insulin (FINS, PINS), homeostasis model assessment for insulin resistance, serum triglyceride, total cholesterol, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol were determined before and after repaglinide treatment.. The allelic frequency of NeuroD1/BETA2 T45 was higher in T2DM patients than in the control subjects [13.45 vs. 6.82%, P < 0.01, odds ratios = 2.342 (1.365, 4.019), P= 0.002]. Type 2 diabetes mellitus patients with the mutated allele of NeuroD1/BETA2 A45T polymorphism showed higher FINS (13.46 ± 12.57 vs. 10.04 ± 7.09 mU l(-1) , P < 0.05) (11.67, 14.83 vs. 8.38, 11.37) and PINS (52.11 ± 40.93 vs. 68.66 ± 43.87 mU l(-1), P < 0.05) (44.89, 58.35 vs. 55.35, 88.87) than individuals with the T allele. The PAX4 R121W R allele carriers had higher PINS (52.11 ± 40.93 vs. 68.66 ± 43.87 mU l(-1), P < 0.05) (44.89, 58.35 vs. 55.35, 88.87) than subjects with the W allele. After repaglinide treatment, patients with the T allele of NeuroD1/BETA2 A45T polymorphisms had attenuated efficacy on fasting plasma glucose (-2.79 ± 2.14 vs.-0.99 ± 1.80 mmol l(-1), P < 0.01) (-3.53, -1.84 vs.-1.99, -0.13) and postprandial plasma glucose (-6.71 ± 5.90 vs.-2.54 ± 3.39 mmol l(-1), P < 0.01) (-9.28, -4.62 vs.-4.34, -0.84). Patients with the RR genotype of PAX4 R121W showed better efficacy with respect to the level of postprandial plasma glucose than R/W genotypes (-6.53 ± 6.52 vs.-2.95 ± 1.17 mmol l(-1), P < 0.05) (-8.20, -4.89 vs.-3.92, -1.20).. The NeuroD1/BETA2 and PAX4 polymorphisms were substantially associated with plasma glucose level after repaglinide monotherapy.

Topics: Adult; Aged; Alleles; Asian People; Basic Helix-Loop-Helix Transcription Factors; Blood Glucose; Carbamates; Case-Control Studies; China; Diabetes Mellitus, Type 2; Female; Genotype; Homeodomain Proteins; Humans; Hypoglycemic Agents; Male; Middle Aged; Paired Box Transcription Factors; Piperidines; Polymorphism, Genetic; Polymorphism, Restriction Fragment Length

Microcirculatory and endothelial dysfunction are signs of cardiovascular engagement in patients with type 2 diabetes. This study tested whether glucose normalisation may reverse this.. Thirty-nine T2DM patients (age 61±7 years, 58% females) with signs of mild diastolic dysfunction were randomised to strict glucose control based on insulin (I-group; n=21) or oral agents (O-group; n=18) for four months. Skin microcirculation was studied with laser Doppler fluxmetry and endothelial function with brachial artery flow-mediated dilatation.. Glucose control improved (reduction of HbA(1c) I-group = -0.5%; O-group -0.7%; p=0.69). Microcirculation improved in the entire group (n=39) determined by foot laser Doppler fluxmetry (32.2±13.6 vs. 35.3±13.1 perfusion units; p<0.001) and laser Doppler fluxmetry following heating (68.8±34.0 vs. 69.3±25.1 PU; p=0.007). Improvement was more consistent with oral agents than insulin. Endothelial function expressed as flow-mediated dilatation decreased in the I-group (6.0±2.2 to 4.7±3.0%; p=0.037) but remained unchanged in the O-group (4.8±2.3 to 5.0±3.7%; n.s.).. Glycaemic normalisation improved skin microcirculation but not endothelial function in patients with type 2 diabetes with mild cardiovascular engagement.

Topics: Administration, Oral; Aged; Biomarkers; Blood Glucose; Brachial Artery; Carbamates; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diastole; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin Aspart; Insulin Glargine; Insulin, Long-Acting; Laser-Doppler Flowmetry; Male; Metformin; Microcirculation; Middle Aged; Piperidines; Prospective Studies; Regional Blood Flow; Skin; Sweden; Time Factors; Treatment Outcome; Vasodilation; Ventricular Dysfunction; Ventricular Function

The aim of this study was to evaluate the pharmacogenetic variability in the disposition of repaglinide in healthy Chinese subjects.. A single dose of 2 mg repaglinide was orally administered to 24 healthy Chinese subjects. The serum concentrations of repaglinide were measured by using liquid chromatography/tandem mass spectrometry. We determined the polymorphic alleles of MDR1 C1236T, MDR1 G2677T/A, MDR1 C3435T, CYP3A4*18, OATP1B1 G388A, and OATP1B1 T521C in each subject.. The area under the plasma concentration-time curve from time 0 to infinity (AUC((0-inf))) of repaglinide was significantly higher in subjects possessing the MDR1 2677GT and 2677TT alleles than in those with the MDR1 2677GG and 2677TA alleles (p = 0.007). The mean AUCs and peak plasma concentration were higher in subjects with the 521TC allele than in those with the OATP1B1 521TT allele, and the OATP1B1 388A allele is associated with a reduced trend of pharmacokinetic exposure; however, these trends were not statistically significant. The pharmacokinetics of repaglinide was not associated with MDR1 C1236T, MDR1 C3435T, and CYP3A4*18.. This study shows that the genetic polymorphisms of MDR1 G2677T/A might explain the variability in the pharmacokinetics of repaglinide in the Chinese population.

Topics: Adult; Alleles; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Asian People; ATP Binding Cassette Transporter, Subfamily B, Member 1; Carbamates; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Genotype; Haplotypes; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Male; Organic Anion Transporters; Piperidines; Polymorphism, Single Nucleotide

The present study evaluated the effects of KCNQ1 rs2237892 and rs2237895 polymorphisms on repaglinide efficacy in Chinese patients with type 2 diabetes mellitus (T2DM). In all, 367 T2DM patients and 214 controls were genotyped. Forty of the T2DM patients were randomly selected to undergo 8 weeks repaglinide treatment. The frequency of the rs2237892 allele was lower in the T2DM patients than in the control group (P < 0.05). The frequency of the rs2237895 C allele was higher in T2DM patients than in healthy control subjects (P < 0.05). Diabetic patients with the rs2237892 risk C allele had lower fasting insulin levels (P < 0.01) and homeostasis model assessment of insulin resistance (HOMA-IR; P < 0.01) values than carriers of the T allele. Diabetic patients with the rs2237895 risk C allele had higher fasting plasma glucose (P < 0.01), postprandial plasma glucose (PPG) levels (P < 0.01) and HOMA-IR values (P < 0.01) than those with the A allele. Following repaglinide treatment, those T2DM patients with the rs2237892 T allele and rs2237895 C allele were more likely to have a positive response to repaglinide in terms of PPG levels (P < 0.05) than T2DM patients with the rs2237892 CC and rs2237895 AA genotypes. In conclusion, KCNQ1 rs2237892 and rs2237895 polymorphisms were found to be associated with the therapeutic efficacy of repaglinide in Chinese T2DM patients.

Topics: Adult; Asian People; Carbamates; Diabetes Mellitus, Type 2; Female; Gene Frequency; Genotype; Humans; KCNQ1 Potassium Channel; Male; Middle Aged; Piperidines; Polymorphism, Genetic; Risk Factors; Treatment Outcome

To investigate a potential relationship between Solute carrier family 30 (zinc transporter) member 8 (SLC30A8) rs13266634 variant and efficacy of rosiglitazone or repaglinide in treating newly diagnosed Chinese type 2 diabetes patients.. A total of 209 diabetic patients without any antihyperglycemic history were recruited and treated with repaglinide or rosiglitazone randomly for 48 weeks (104 and 105 patients, respectively). Anthropometric measurements and clinical laboratory tests were carried out before and after the treatment. An non-synonymous variant rs13266634 was genotyped by matrix-assisted laser desorption ionization-time of flight mass spectroscopy.. Ninety-one patients in repaglinide group and ninety-three patients in rosiglitazone group completed the study. Δ value of homeostasis model assessment of beta cell function (HOMA-B) and Δ value of fasting proinsulin levels were statistically significant between three genotype groups (P=0.0149 and 0.0246, respectively) after rosiglitazone treatment. However, no genotype association was observed in the repaglinide or rosiglitazone group with other parameters.. The SLC30A8 variant was associated with the efficacy of insulin sensitizer monotherapy on insulin secretion in patients with newly diagnosed type 2 diabetes mellitus in Shanghai, China.

Topics: Carbamates; Cation Transport Proteins; China; Diabetes Mellitus, Type 2; Female; Gene Frequency; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Polymorphism, Single Nucleotide; Rosiglitazone; Thiazolidinediones; Zinc Transporter 8

Therapeutic doses of gemfibrozil cause mechanism-based inactivation of CYP2C8 via formation of gemfibrozil 1-O-β-glucuronide. We investigated the extent of CYP2C8 inactivation caused by three different doses of gemfibrozil twice dailyfor 5 days, using repaglinide as a probe drug, in 10 healthy volunteers. At the end of this 5-day regimen, there were dose-dependent increases in the area under the plasma concentration–time curve from 0 to infinity (AUC0–∞) of repaglinide by3.4-, 5.5-, and 7.0-fold corresponding to 30, 100, and 600 mg of gemfibrozil, respectively, as compared with the control phase (P < 0.001). On the basis of a mechanism-based inactivation model involving gemfibrozil 1-O-β-glucuronide, a gemfibrozil dose of 30 mg twice daily was estimated to inhibit CYP2C8 by >70% and 100 mg twice daily was estimated to inhibit it by >90%. Hence, gemfibrozil is a strong inactivator of CYP2C8 even in very small, subtherapeutic, multiple doses. Administration of small gemfibrozil doses may be useful in optimizing the pharmacokinetics of CYP2C8 substrate drugs and in reducing the formation of their potentially toxic metabolites via CYP2C8.

Topics: Area Under Curve; Aryl Hydrocarbon Hydroxylases; Blood Glucose; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP2C8; Dose-Response Relationship, Drug; Enzyme Inhibitors; Gemfibrozil; Genotype; Glucuronides; Humans; Liver-Specific Organic Anion Transporter 1; Organic Anion Transporters; Piperidines

studies in younger patients with diabetes have shown that insulin profiles are more physiologic and postprandial glucose levels are lower with repaglinide than with glyburide. We conducted this study to determine if the differences in insulin/glucose profiles between repaglinide and glyburide were similar or different in the elderly.. thirteen elderly patients with diabetes were given glyburide or repaglinide in randomized crossover design, followed by a meal tolerance test. Samples were taken at regular intervals to measure glucose and insulin values.. the 0-30 min area under the curve (AUC) for insulin was higher (glyburide, 294  ±  37 pM; repaglinide, 382  ±  39 pM) (P < 0.01), and the 180-240 min AUC for insulin was lower (glyburide, 325  ±  50 pM; repaglinide, 196 ± 20 pM) (P < 0.01) with repaglinide. The 0-240 min AUC for glucose was not different between treatments (glyburide, 7.4 ±  0.5 mM; repaglinide, 7.1 ±  0.3 mM) (P = not significant). Five subjects treated with glyburide and no subjects treated with repaglinide required glucose from 180 to 240 min (P < 0.05, Fisher's exact test).. we conclude that repaglinide results in a more physiologic insulin profile and less frequent hypoglycemia than glyburide in the elderly.

Topics: Aged; Area Under Curve; Blood Glucose; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Female; Glyburide; Humans; Hypoglycemic Agents; Insulin; Male; Piperidines; Postprandial Period

Metformin has been reported to reduce α-dicarbonyls, which are known to contribute to diabetic complications. It is unclear whether this is due to direct quenching of α-dicarbonyls or to an improvement in glycemic control. We therefore compared the effects of metformin versus repaglinide, an antihyperglycemic agent with an insulin-secreting mechanism, on the levels of the α-dicarbonyl 3-deoxyglucosone (3DG).. We conducted a single-center, double-masked, double-dummy, crossover study involving 96 nonobese patients with type 2 diabetes. After a 1-month run-in on diet-only treatment, patients were randomized to either repaglinide (6 mg daily) followed by metformin (2 g daily) or vice versa each during 4 months with a 1-month washout between interventions.. 3DG levels decreased after both metformin (-19.3% (95% confidence interval (CI): -23.5, -14.8)) and repaglinide (-20.8% (95% CI: -24.9, -16.3)) treatments, but no difference was found between treatments (1.8% (95% CI: -3.8, 7.8)). Regardless of the treatment, changes in glycemic variables were associated with changes in 3DG. Specifically, 3DG decreased by 22.7% (95% CI: 19.0, 26.5) per s.d. decrease in fasting plasma glucose (PG), by 20.0% (95% CI: 16.2, 23.9) per s.d. decrease in seven-point mean plasma glucose, by 22.5% (95% CI: 18.6, 26.6) per s.d. decrease in area under the curve for PG, by 17.2% (95% CI: 13.8, 20.6) per s.d. decrease in HbAlc, and by 10.9% (95% CI: 6.4, 15.5) per s.d. decrease in Amadori albumin. In addition, decreases in 3DG were associated with decreases in advanced glycation endproducts and endothelial markers.. Improved glycemic control induced by both metformin and repaglinide is associated with a reduction in 3DG levels in nonobese individuals with type 2 diabetes. This may constitute a shared metabolic pathway through which both treatments have a beneficial impact on the cardiovascular risk.

Topics: Carbamates; Confidence Intervals; Deoxyglucose; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Metformin; Piperidines

The aim of this study was to explore the impact of KCNQ1 variants on the responses to oral antidiabetic drugs in a Chinese study population. A 48-week randomized pharmacogenetics study compared the effects of repaglinide and rosiglitazone in 209 newly diagnosed patients with type 2 diabetes. In the repaglinide cohort, individuals who were rs2237892 TT homozygotes exhibited lower 2-h glucose levels and significantly higher cumulative attainment rates of target 2-h glucose levels (P(log-rank) = 0.0383) than the C allele carriers; patients with a greater number of rs2237892 C alleles showed larger augmentations in both fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) (P = 0.0166 and 0.0026, respectively); moreover, the rs2237895 C allele was also associated with greater increments in both fasting insulin and HOMA-IR (P = 0.0274 and 0.0259, respectively). In contrast, only an association between rs2237897 and decrease in 2-h glucose levels was detected in the rosiglitazone cohort (P = 0.0321). Our results indicated that KCNQ1 polymorphisms are associated with repaglinide efficacy, and might also be associated with rosiglitazone response, in Chinese patients with type 2 diabetes.

Topics: Administration, Oral; Adult; Alleles; Asian People; Blood Glucose; Carbamates; China; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Homeostasis; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; KCNQ1 Potassium Channel; Male; Middle Aged; Pharmacogenetics; Piperidines; Polymorphism, Single Nucleotide; Rosiglitazone; Thiazolidinediones

Both repaglinide and gliclazide are insulin secretagogues widely used in the treatment of type 2 diabetes. They stimulate insulin secretion through distinct mechanisms and may benefit patients from different aspects. The present study was to evaluate the effects of repaglinide or gliclazide on glycaemic control, insulin secretion, and lipid profiles in type 2 diabetes patients.. A total of 47 newly diagnosed type 2 diabetes patients were randomized 1:1 to receive a 4-week treatment with repaglinide or gliclazide. The standard mixed meal tolerance test was performed before and after the treatment. Plasma glucose (PG), insulin concentration, and lipid profiles were measured. The area under insulin concentration curve (AUC(ins)) and the early-phase insulin secretion index (ΔI(30)/ΔG(30)) were calculated.. After the trial, fasting and postprandial PG and postprandial insulin improved significantly in both groups (P < 0.05). The maximum insulin concentration occurred earlier in the repaglinide group than that in the gliclazide group. AUC(ins) increased in both groups (P < 0.05), but no significant difference was found between groups. ΔI(30)/ΔG(30) increased in both groups (P < 0.05), especially in the repaglinide group (P < 0.05). Triglyceride and total cholesterol decreased significantly in the repaglinide group in some time points, while no significant change was observed in the gliclazide group.. Repaglinide and gliclazide had similar effects on glycaemic control and total insulin secretion, while repaglinide had more effects on improvements in β-cell function and lipid metabolism.

Topics: Adult; Blood Glucose; Carbamates; Cholesterol; Diabetes Mellitus, Type 2; Fasting; Female; Gliclazide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Middle Aged; Piperidines; Postprandial Period; Treatment Outcome; Triglycerides

To study the time to onset of mechanism-based inactivation of cytochrome P450 (CYP) 2C8 by gemfibrozil in vivo, we conducted a randomized five-phase crossover study in 10 healthy volunteers. In one phase the volunteers ingested 0.25 mg of repaglinide alone (control), and in the other phases they received 600 mg of gemfibrozil 0-6 h prior to the repaglinide dose. When gemfibrozil was taken 0, 1, 3, or 6 h before repaglinide, the geometric mean ratio relative to control (90% confidence interval (CI)) of repaglinide area under the plasma concentration-time curve (AUC(0-∞)) was 5.0-fold (4.3-5.7-fold), 6.3-fold (5.4-7.5-fold), 6.6-fold (5.6-7.7-fold), and 5.4-fold (4.8-6.1-fold), respectively (P < 0.001 vs. control). The geometric mean ratio relative to control (90% CI) of the maximum plasma concentration (C(max)) of the CYP2C8-mediated metabolite M4 was 1.0-fold (0.8-1.3-fold), 0.10-fold (0.06-0.17-fold, P < 0.001), 0.06-fold (0.04-0.10-fold, P < 0.001), and 0.09-fold (0.05-0.14-fold, P < 0.001), respectively. The strong inactivation of CYP2C8, evident as soon as 1 h after gemfibrozil dosing, has implications in clinical practice and in studies with gemfibrozil as a CYP2C8 model inhibitor.

Topics: Adult; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP2C8; Female; Gemfibrozil; Glucuronates; Humans; Hypoglycemic Agents; Male; Piperidines; Time Factors

Gemfibrozil 1-O-β-glucuronide inactivates CYP2C8 irreversibly. We investigated the effect of gemfibrozil dose on CYP2C8 activity in humans using repaglinide as a probe drug. In a randomized, five-phase crossover study, 10 healthy volunteers ingested 0.25 mg of repaglinide 1 h after different doses of gemfibrozil or placebo. Concentrations of plasma repaglinide, gemfibrozil, their metabolites, and blood glucose were measured. A single gemfibrozil dose of 30, 100, 300, and 900 mg increased the area under the concentration-time curve of repaglinide 1.8-, 4.5-, 6.7-, and 8.3-fold (P < 0.001), and its peak concentration 1.4-, 1.7-, 2.1-, and 2.4-fold (P < 0.05), compared with placebo, respectively. Gemfibrozil pharmacokinetics was characterized by a slightly more than dose-proportional increase in the area under the curve of gemfibrozil and its glucuronide. The gemfibrozil-repaglinide interaction could be mainly explained by gemfibrozil 1-O-β-glucuronide concentration-dependent, mechanism-based inhibition of CYP2C8, with a minor contribution by competitive inhibition of organic anion-transporting polypeptide 1B1 at the highest gemfibrozil dose. The findings are consistent with ∼50% inhibition of CYP2C8 already with a single 30-mg dose of gemfibrozil and >95% inhibition with 900 mg. In clinical drug-drug interaction studies, a single 900-mg dose of gemfibrozil can be used to achieve nearly complete inactivation of CYP2C8.

Topics: Adult; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Blood Glucose; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP2C8; Dose-Response Relationship, Drug; Double-Blind Method; Drug Interactions; Female; Gemfibrozil; Genotype; Humans; Male; Organic Anion Transporters; Piperidines; Young Adult

The aim of this research is to determine efficacy and safety of repaglinide alone and in combination with metformin in Chinese subjects with type 2 diabetes naive to oral antidiabetes therapy.. A 16-week, open-label, randomized, active-controlled, parallel-group trial was carried out. Subjects were randomized (1:1) to repaglinide 1 mg t.i.d. (maximum dose, 4 mg t.i.d.) or repaglinide plus metformin 1 mg/500 mg t.i.d. (maximum dose, 4 mg/500 mg t.i.d.). Eligible subjects (18 - 75 years old) had type 2 diabetes, A1C > 8.5%, BMI ≤ 35 kg/m(2), and were naive to oral antidiabetes agents.. The primary outcome was A1C reduction. Secondary end points included fasting plasma glucose (FPG), 2-h postprandial glucose (PPG), and 7-point plasma glucose. Baseline characteristics (repaglinide/metformin, n = 218; repaglinide-only, n = 214) were similar between groups. Mean A1C reduction (± SD) was 4.51 ± 1.64% (combination) and 4.05 ± 1.59% (monotherapy). Estimated mean treatment difference for repaglinide/metformin versus repaglinide-only was -0.30% (95% CI -0.49 to -0.11; p < 0.01). Combination treatment demonstrated significant improvements versus monotherapy in FPG, 7-point plasma glucose, and lunchtime and dinnertime 2-h PPG (all p < 0.05). Hypoglycemia rates were 2.04 (combination) versus 1.35 (monotherapy) events/subject-year (p = 0.058). Adverse events were comparable between groups.. Repaglinide plus metformin and repaglinide alone provided significant improvements in glycemic control and were well tolerated in Chinese patients naive to treatment with oral antidiabetes agents. Combination therapy with repaglinide plus metformin showed superiority to repaglinide monotherapy in this population. Limitations of this study are that subjects were newly diagnosed and had high mean baseline A1C, which may affect generalizability of results.

Topics: Adolescent; Adult; Aged; Blood Glucose; Carbamates; China; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Young Adult

St John's wort (SJW; Hypericum perforatum) has been one of the most commonly used herbal remedies for mood disorders. This study aimed to investigate the effect of SJW, a pregnane X receptor (PXR) agonist, on the pharmacokinetics and pharmacodynamics of repaglinide, a widely consumed glucose-lowering drug.. In a two-phase, randomized, crossover study with a 4-week washout period between phases, 15 healthy subjects with specific solute carrier organic anion transporter family member 1B1 (SLCO1B1) genotypes were given pretreatment with SJW 325 mg or placebo three times daily for 14 days, and a single dose of repaglinide 1 mg was administered followed by 75 g glucose at 15 minutes after repaglinide administration.. In all subjects, SJW had no effect on the total area under the plasma concentration-time curve from time zero to infinity (AUC(∞)), the peak plasma concentration (C(max)) or the elimination half-life (t(½)) of repaglinide. In addition, SJW had no significant effect on the blood glucose-lowering and insulin-elevating effects of repaglinide.. Consumption of SJW for 14 days had no clinically significant effect on the pharmacokinetics and pharmacodynamics of repaglinide.

Topics: Carbamates; Cross-Over Studies; Cytochrome P-450 Enzyme System; Depression; Genotype; Herb-Drug Interactions; Humans; Hypericum; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Organic Anion Transporters; Phytotherapy; Piperidines; Placebos; Plant Extracts; Pregnane X Receptor; Receptors, Steroid; Young Adult

To examine the effects of glibenclamide and repaglinide on glucose stimulated insulin release, incretins, oxidative stress and cell adhesion molecules in patients with type 2 diabetes suboptimally treated with metformin.. A randomized clinical trial was performed recruiting 27 subjects (HbA(1c) between 7.5 and 10.5%) free from cardiovascular and renal disease. Glucose, insulin, C-peptide, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), total antioxidant status, F(2)-isoprostane, interleukin-6 and cell adhesion molecules were measured during an oral glucose load at baseline and after eight weeks of treatment. The areas under the curve were analysed at 45, 60 and 120 min (AUC(45), AUC(60), AUC(120)).. Significant improvements in glucose were observed with repaglinide (HBA(1c): -1.5%, fasting glucose: -2.8 mmol/L, 2-h glucose: -3.7 mmol/L, AUC(120): -18.9%) and glibenclamide (-1.0%, -2.2 mmol/L, -2.5 mmol/L, -17.5%). Repaglinide was also associated with an increase in the AUC(60) and AUC(120) for insulin (+56%, +61%) and C-peptide (+41%, +36%). GLP-1, GIP, IL-6, ICAM-1 and E-selectin levels did not change in either group. No association was observed between GLP-1, GIP-1 and plasma markers of oxidative stress.. Repaglinide is associated with improved postprandial glycaemic control via insulin and C-peptide release. We observed no direct effects of glibenclamide or repaglinide on plasma levels of GLP-1 or GIP. We observed no associations of GLP-1 and GIP with plasma markers of oxidative stress.

Topics: Adult; Aged; Analysis of Variance; Biomarkers; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Drug Therapy, Combination; E-Selectin; F2-Isoprostanes; Female; Gastric Inhibitory Polypeptide; Glucagon-Like Peptide 1; Glyburide; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemic Agents; Incretins; Insulin; Intercellular Adhesion Molecule-1; Interleukin-6; Male; Metformin; Middle Aged; Oxidative Stress; Piperidines; Postprandial Period; Time Factors; Treatment Outcome; Wales

Deferasirox, a newly developed iron chelator, was coadministered orally with either a known inducer of drug metabolism or with cosubstrates for cytochrome P450 (CYP) to characterize the potential for drug-drug interactions. In the induction assessment, single-dose deferasirox pharmacokinetics were obtained in the presence and absence of a repeated-dose regimen of rifampin. In the CYP3A interaction evaluation, midazolam and its active hydroxylated metabolite were assessed after single doses of midazolam in the presence and absence of steady-state concentrations of deferasirox. To test for interaction at the level of CPY2C8, single-dose repaglinide pharmacokinetics/pharmacodynamics were determined with and without repeated-dose administration of deferasirox. After rifampin, a significant reduction (44%) in plasma exposure (AUC) to deferasirox was observed. Upon coadministration of midazolam, there was a modest reduction of up to 22% in midazolam exposure (AUC, C(max)), suggesting a modest induction of CYP3A4/5 by deferasirox. Def erasirox caused increases in repaglinide plasma C(max) and AUC of 1.5-fold to over 2-fold, respectively, with little change in blood glucose measures. Specific patient prescribing recommendations were established when coadministering deferasirox with midazolam, repaglinide, and rifampin. These recommendations may also apply to other substrates of CYP3A4/5 and CYP2C8 or potent inducers of glucuronidation.

Topics: Adult; Anesthetics, Intravenous; Aryl Hydrocarbon Hydroxylases; Benzoates; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Deferasirox; Drug Interactions; Enzyme Inhibitors; Female; Humans; Hypoglycemic Agents; Iron Chelating Agents; Male; Midazolam; Piperidines; Rifampin; Triazoles

This study showed that the polymorphisms KCNJ11 Lys23Glu and TCF7L2 rs290487(C/T) are associated with a heightened risk of developing type 2 diabetes mellitus (T2DM). We also explored the effects of these polymorphisms on the efficacy of repaglinide therapy in Chinese patients with T2DM. A total of 259 patients with T2DM and 188 healthy controls were genotyped. Forty patients with various genotypes were randomly selected to undergo an 8-week repaglinide treatment regimen. Patients with the G allele of the KCNJ11 Lys23Glu polymorphism showed higher levels of fasting plasma glucose (FPG) and postprandial plasma glucose (PPG) (P < 0.05). After repaglinide treatment, patients with the GA or AA genotype showed higher levels of FPG, PPG, and glycated hemoglobin (HbA(1c)) compared with patients with the GG genotype (P < 0.05). Patients with the C allele of TCF7L2 rs290487(C/T) had higher total cholesterol levels and lower body mass index (BMI) (P < 0.05). In patients with the TT genotype, the drug showed better efficacy with respect to levels of fasting insulin, triglycerides, and low-density lipoprotein cholesterol (LDL-c) than in patients with the CC or CT genotype (P < 0.05). The KCNJ11 and TCF7L2 polymorphisms were associated with repaglinide efficacy.

Topics: Adult; Alleles; Amino Acid Substitution; Asian People; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Female; Glutamic Acid; Humans; Lysine; Male; Middle Aged; Piperidines; Polymorphism, Genetic; Potassium Channels, Inwardly Rectifying; Risk Factors; TCF Transcription Factors; Transcription Factor 7-Like 2 Protein; Treatment Outcome

To compare effects of three different insulin secretagogues on early-phase insulin secretion, metabolism of glucose and lipids, and lipid peroxidation in newly diagnosed Type 2 Diabetes Mellitus (T2DM).. Totally 60 newly diagnosed T2DM outpatients were randomized to three groups with 1-month monotherapy of repaglinide (Rg), glimepiride (Gm) or gliclazide MR (Gli), respectively. Some indexes of early-phase insulin secretion, glucose, lipids, and lipid peroxidation were inspected.. Fasting plasma glucose (FPG), glycosylated hemoglobin (HbA(1c)) and fructosamine (FA) were improved in all groups similarly (p>0.05). Rg group was with the highest early-phase insulin secretion index (DeltaI30/DeltaG30) (p=0.026), lower mean amplitude of glycaemic excursion (MAGE) (p<0.05), lowest mean peak value of post-lunch glucose (p=0.043), and lowest postprandial triglyceride (TG) (p=0.039). Postprandial free fatty acid (FFA) was lower after Rg and Gli treatment (p<0.05). Serum 8-iso prostaglandin F(2alpha) (8-iso PGF(2alpha)) was improved in all groups, but the improvement showed statistically significant only in Rg group (p=0.04).. Rg, Gm and Gli can all decrease blood glucose effectively in newly diagnosed T2DM patients, while Rg performs outstandingly in the aspects of improving early-phase insulin secretion, glucose excursion, postprandial lipids and 8-iso PGF(2alpha).

Topics: Adult; Aged; Analysis of Variance; Blood Glucose; Carbamates; Chi-Square Distribution; Diabetes Mellitus, Type 2; Female; Fructosamine; Gliclazide; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Lipid Peroxidation; Lipids; Male; Middle Aged; Oxidative Stress; Piperidines; Postprandial Period; Sulfonylurea Compounds; Treatment Outcome

A progressive weight gain is associated with various pharmacological options improving glycemic control in type 2 diabetes mellitus (T2DM). Ghrelin has been implicated in the regulation of feeding behavior and energy balance in humans. Based on evidence that functional ATP-sensitive channels are present in ghrelin-producing cells, we hypothesized that meglitinides may affect circulating ghrelin levels in subjects with type 2 diabetes.. In a single-blinded randomized three-period crossover study (n = 20), repaglinide or nateglinide was given in combination with metformin for two treatment periods over a 1-week period, respectively, separated by a 1-week treatment with placebo. Liquid meal challenge tests (LMCTs) with single preprandial doses of repaglinide (2 mg), nateglinide (120 mg), or placebo were performed at the end of each treatment period. Ten control subjects without diabetes underwent a single LMCT without any medication.. Fasting ghrelin concentrations were not different between all treatments and between patients with diabetes and control subjects. Subjects with T2DM treated with placebo showed no suppression of ghrelin in the LMCT. After administration of meglitinides a nadir of serum ghrelin was observed at 60 min (8.6% of baseline [P = 0.038] for repaglinide and 7.5% of baseline [P = 0.081] for nateglinide), which was similar to the secretion pattern seen in control subjects. No correlations between postprandial insulin or glucose levels and circulating ghrelin concentrations were observed.. Treatment with meglitinides reconstructed postprandial ghrelin secretion patterns to those of controls without diabetes. This observation may help to improve the control of feeding behavior in patients with T2DM.

Topics: Adult; Aged; Benzamides; Blood Glucose; Body Mass Index; C-Peptide; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Eating; Feeding Behavior; Ghrelin; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Metformin; Middle Aged; Piperidines; Reference Values; Single-Blind Method

The traditional sulfonylureas with long half-lives have sustained stimulatory effects on insulin secretion compared to the short-acting insulin secretagogue. In this study, we used the frequently sampled intravenous glucose tolerance test (FSIGT) to evaluate the insulin sensitivity (IS), glucose sensitivity (SG), and acute insulin response after glucose load (AIRg) after 4 months treatment with either gliclazide or repaglinide. The design of study was randomizedcrossover. We enrolled 20 patients with new-onset type 2 diabetes (mean age, 49.3 years). Totally three FSIGTs were performed, one before and one after each of the two treatment periods as aforementioned. No significant differences in fasting plasma glucose, insulin, body mass index, blood pressure, glycated hemoglobin, or lipids were noted between the two treatments. After the repaglinide treatment, higher AIRg, lower IS, and lower SG were noted, but they did not reach statistical significance. The disposal index (DI) was also not significantly different between the two treatments. In conclusion, since non-significantly higher DI, AIRg, lower IS and SG were noted after repaglinide treatment, it might be a better treatment for diabetes, relative to gliclazide.

Topics: Adult; Blood Glucose; Blood Pressure; Body Mass Index; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Female; Gliclazide; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Piperidines; Time Factors; Treatment Outcome

Our aim was to study, at the same glycemic control, how treatment with either the insulin secretagogue repaglinide or exogenous insulin aspart affects endogenous insulin secretion, plasma insulin and IAPP (islet amyloid polypeptide) levels, GH-IGF (growth hormone-insulin-like growth factor) axis and plasma lipoprotein concentrations in patients with type 2 diabetes. Five patients, age 65.0+/-4.1 years (mean+/-SE), body weight 82.5+/-5.0 kg, BMI (body mass index) 27.7+/-1.5 kg/m(2) were treated for 10 weeks with repaglinide or insulin aspart in a randomized, cross-over study. At the end of each treatment a 24-h metabolic profile was performed. Blood glucose, C-peptide, free human insulin, free total (human and analogue) insulin, proinsulin, IAPP, IGF-I, IGFBP-1 (IGF binding protein-1), GHBP (growth hormone binding protein) and plasma lipoprotein concentrations were measured. Similar 24-h blood glucose profiles were obtained with repaglinide and insulin aspart treatment. During the repaglinide treatment, the meal related peaks of C-peptide and free human insulin were about twofold higher than during treatment with insulin aspart. Proinsulin, GHBP were higher and IAPP levels tended to be higher during repaglinide compared to insulin aspart. Postprandial plasma total cholesterol, triglycerides and apolipoprotein B concentrations were higher on repaglinide than on insulin aspart treatment. Our results show that, at the same glycemic control, treatment with exogenous insulin aspart in comparison with the insulin secretagogue repaglinide result in a lower endogenous insulin secretion, and a tendency towards a less atherogenic postprandial lipid profile.

Topics: Aged; Apolipoproteins; Blood Glucose; C-Peptide; Carbamates; Cholesterol; Cross-Over Studies; Diabetes Mellitus, Type 2; Drug Administration Schedule; Female; Humans; Hypoglycemic Agents; Insulin; Insulin Aspart; Insulin-Like Growth Factor Binding Protein 1; Insulin-Like Growth Factor I; Lipids; Lipoproteins; Male; Middle Aged; Piperidines; Proinsulin

The purpose of this study is to evaluate efficacy and safety of nateglinide tablet administration in comparison with those of repaglinide tablet as control on treating type 2 diabetes mellitus in China. Pooled-analysis with analysis of covariance (ANCOVA) method was applied to assess the efficacy and safety based on original data collected from four independent randomized clinical trials with similar research protocols. However meta-analysis was applied based on the outcomes of the four studies. The results by meta-analysis were comparable to those obtained by pooled-analysis. The means of HbA(1c), and fasting blood glucose in both the nateglinide and repaglinide groups were reduced significantly after 12 weeks duration but no statistical differences in reduction between the two groups. The adverse reaction rates were 9.89 and 6.51% in the nateglinide and repaglinide groups respectively, with the rate difference showing no statistical significance, and the Odds Ratio of adverse reaction rate (95% confidence interval) was 1.59 (0.99, 2.55). Both nateglinide and repaglinide administration have similarly significant effects on reducing HbA(1c) and FBG. However, the adverse reaction rate in the nateglinide group is higher than that in the latter using repaglinide but no statistical significance difference as revealed in the four clinical trials detailed below.

Topics: Carbamates; China; Cyclohexanes; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines

To compare the metabolic effects of acarbose and repaglinide in type 2 diabetic patients who are being treated with a sulphonylurea-metformin combination therapy. The primary endpoint of the study was to evaluate which add-on treatment between acarbose and repaglinide is more efficacious in reducing PPG. The second endpoint was to evaluate which of these two treatment is more efficacious in the global management of glucose homeostasis in the enrolled patients.. After a 4-week run-in period with a sulphonylurea-metformin combination, 103 patients were randomised to receive in addition either repaglinide, up to 6 mg/day (2 mg three times a day) or acarbose, up to 300 mg/day (100 mg three times a day) with forced titration (independently of their glycaemic control, unless side-effects developed due to the drug dosage) for 15 weeks. The treatment was then crossed-over for further 12 weeks until the 27th week. We assessed body mass index (BMI), glycosylated haemoglobin (HbA(1c)), fasting plasma glucose (FPG), postprandial plasma glucose (PPG), fasting plasma insulin (FPI), postprandial plasma insulin (PPI), homeostatic model assessment (HOMA) index, systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (Tg), at baseline and at 1, 2, 15 and 27 weeks of treatment.. Seven patients did not complete the study, comprising one patient who was lost to follow-up and a further six through side-effects (two in week 1, one in week 15 and three after cross-over) Side-effects were classified as nausea (one in acarbose group), gastrointestinal events (four in acarbose group), and hypoglycaemia (one in repaglinide group). After 15 weeks of therapy, the repaglinide-treated patients experienced a significant decrease in HbA(1c) (-1.1%, p < 0.05), FPG (-9.5%, p < 0.05), and PPG (-14.9%, p < 0.05), when compared to the baseline values. However, the same treatment was associated with a significant increase in body weight (+2.3%, p < 0.05), BMI (+3.3%, p < 0.05) and FPI (+22.5%, p < 0.05); The increase was reversed during the cross-over phase. After 15 weeks of therapy, the acarbose-treated patients experienced a significant decrease in body weight (-1.9%, p < 0.05), BMI (-4.1%, p < 0.05), HbA(1c) (-1.4%, p < 0.05), FPG (-10.7%, p < 0.05), PPG (-16.2%, p < 0.05), FPI (-16.1%, p < 0.05), PPI (-26.9%, p < 0.05), HOMA index (-30.1%, p < 0.05), when compared to the baseline values. All these changes were reversed during the cross-over study phase, except those relating to HbA(1c), FPG and PPG. The only changes that significantly differed when directly comparing acarbose- and repaglinide-treated patients were those relating to FPI (-16.1% vs. +22.5%, respectively, p < 0.05) and HOMA index (-30.1% vs. +2.7%, p < 0.05).. In addition from having a similar effect to repaglinide on PPG, acarbose appeared to have a more comprehensive positive effect on glucose metabolism compared to repaglinide in this relatively small sample of type 2 diabetic patients when used as add-on therapy to sulphonylureas and metformin.

Topics: Acarbose; Administration, Oral; Adult; Blood Glucose; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Therapy, Combination; Female; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Sulfonylurea Compounds

Combinations of insulin and oral antidiabetic drugs (OAD) are often prescribed instead of insulin alone. In this study, the effects of insulin glargine (IG) in combination with repaglinide or acarbose on glycemic parameters were investigated. Obese Type 2 diabetic patients with fasting blood glucose (FBG) levels >or= 7.7 mmol/l [corrected] and hemoglobin glycated (A1C) >or=9% under maximal OAD combination therapy were enrolled. Previous therapies were discontinued, and patients were randomized into 2 groups. The combinations of IG and repaglinide were administered to group 1, and of IG and acarbose to group 2 for 13 weeks. Twenty patients in group 1 and 18 patients in group 2 completed the study. A1C levels were significantly decreased from 10.9+/-1.4% to 7.7+/-1.1% in group 1 and 11.0+/-1.4% to 8.1+/-1.4% in group 2. FBG levels were significantly decreased from 11.9+/-2.7 to 7.1+/-2.3 mmol/l in group 1 and 11.1+/-2.5 to 6.8+/-1.4 mmol/l in group 2. Post-prandial glucose levels were significantly decreased from 15.3+/-3.8 to 10.3+/-3.0 mmol/l in group 1 and 14.0+/-3.1 to 8.9+/-2.2 mmol/l in group 2. Intergroup comparisons indicated no significant differences. More weight gain was detected in group 1, compared to the baseline. Symptomatic hypoglycemia incidence was similar in both groups. Severe hypoglycemic attacks were seen in two patients in group 1. Flatulence incidence was higher in acarbose group. Conclusively, repaglinide and acarbose were equally effective when combined with IG for obese Type 2 diabetic patients controlled inadequately with OAD alone. Furthermore, acarbose seems to have advantages over repaglinide concerning weight gain and severe hypoglycemic attacks.

Topics: Acarbose; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Glargine; Insulin, Long-Acting; Male; Middle Aged; Obesity; Piperidines; Weight Gain

To assess the use of a new repaglinide/metformin fixed-dose combination (FDC) tablet for the treatment of type 2 diabetes.. In this 26-week, multicentre, open-label, parallel-group trial, subjects poorly controlled with mono- or dual-oral antidiabetic therapy were randomized 1 : 1 : 1 to receive a repaglinide/metformin FDC tablet either two times daily (BID) or three times daily (TID) or a rosiglitazone/metformin FDC tablet BID. The primary objective comprised two hypotheses tested in a hierarchical order: (i) that treatment with the repaglinide/metformin FDC BID is non-inferior to that of a rosiglitazone/metformin FDC tablet BID as measured by changes in haemoglobin A1c (HbA1c) (results presented here) and (ii) if true, that treatment with the repaglinide/metformin FDC BID was non-inferior to that of the repaglinide/metformin FDC TID as measured by changes in HbA1c (results presented in a companion paper). Additional efficacy and safety end-points were also assessed.. Of the 561 subjects randomized, 383 completed the study. Reductions in HbA1c values became apparent at earlier times for repaglinide/metformin FDC BID treatment than rosiglitazone/metformin FDC BID, and final changes in HbA1c were not significantly different between treatment arms (p = 0.8186); thus, the predefined statistical criterion for non-inferiority was met. Overall adverse event profiles were comparable between treatment groups, and no major hypoglycaemic episodes were reported during the study.. The repaglinide/metformin FDC BID regimen showed efficacy that was non-inferior to that of the rosiglitazone/metformin FDC BID regimen currently in clinical use and a more rapid reduction of HbA1c values. Thus, repaglinide/metformin FDC BID is a clinically feasible alternative to rosiglitazone/metformin FDC BID.

Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Lipids; Male; Metformin; Middle Aged; Patient Satisfaction; Piperidines; Rosiglitazone; Tablets; Thiazolidinediones; Young Adult

To assess the efficacy and safety of a new repaglinide/metformin fixed-dose combination (FDC) tablet administered either twice a day (BID) or three times a day (TID) for the management of type 2 diabetes.. This was a 26-week, multicentre, open-label parallel trial in which subjects poorly controlled with mono- or dual-oral antidiabetic therapy were randomized 1 : 1 : 1 to instead receive repaglinide/metformin FDC either BID or TID or a rosiglitazone/metformin FDC BID. Two primary hypotheses were tested in a hierarchical manner: (i) treatment with the repaglinide/metformin FDC BID is non-inferior to that of the rosiglitazone/metformin FDC BID as measured by changes in haemoglobin A1c (HbA1c) (results presented in companion paper) and (ii) repaglinide/metformin BID is non-inferior to repaglinide/metformin TID (as measured by changes in HbA1c). Additional efficacy and safety end-points were also assessed.. A total of 561 subjects were randomized; 383 completed the study. Repaglinide/metformin FDC BID was non-inferior to repaglinide/metformin FDC TID with respect to HbA1c. Additionally, changes in mean fasting plasma glucose values from baseline to end of study were not significantly different between the BID and the TID dose groups. There were no major hypoglycaemic episodes reported in either group during the trial, and overall adverse event profiles were similar.. The efficacy of twice-daily dosing of a repaglinide/metformin FDC tablet was non-inferior to that of three-times-daily dosing.

Topics: Adult; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Metformin; Middle Aged; Patient Satisfaction; Piperidines; Tablets; Young Adult

An impaired early phase of insulin secretion in the type 2 diabetes mellitus (DM) is very important for the postprandial hyperglycemia. The aim of the study was to compare the efficacy of metformin/repaglinid and metformin/glimepirid regimes in type 2 diabetics uncontrolled with metformin monotherapy.. Totally, 60 type 2 diabetics with haemoglobin A1c > or = 7.5% and 2000 mg of metformin monotherapy for at least three months were divided in the following groups: A-30 patients with metformin+repaglinid (2 mg for each meal) and B metformin+glimepirid (3 mg in the morning). Assessment of the regimes efficacy comprised of haemoglobin A1c, fasting blood glucose (FBG) and postprandial blood glucose (PBG). Assessment of the safety was performed on the basis of recorded hypoglycemia (<4.0 mmol/l).. In both groups, FBG was significantly lower at the end of the study. In the group A it decreased from 9.03 +/- 1.00 to 7.32 +/- 0.65 (p < 0.001), in the group B from 8.94 +/- 1.01 to 7.23 +/- 0.70 (p < 0.001). There was no statistical difference between the groups. PBG was significantly lower after 12 weeks in both groups.. Metformin/repaglinid is an efficient and safe therapeutic regime in the treatment of the type 2 DM that ensure a better control of PBG levels (Tab. 4, Ref. 18).

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Sulfonylurea Compounds

Gemfibrozil 1-O-beta-glucuronide is a mechanism-based inhibitor of cytochrome P450 2C8. We studied the recovery of CYP2C8 activity after discontinuation of gemfibrozil treatment using repaglinide as a probe drug, to estimate the in vivo turnover half-life of CYP2C8. In a randomized five-phase crossover study, nine healthy volunteers ingested 0.25 mg of repaglinide alone or after different time intervals after a 3-day treatment with 600 mg of gemfibrozil twice daily. The area under the plasma concentration-time curve (AUC) from time 0 to infinity of repaglinide was 7.6-, 2.9-, 1.4- and 1.0-fold compared with the control phase when it was administered 1, 24, 48, or 96 h after the last gemfibrozil dose, respectively (P < 0.001 versus control for 1, 24, and 48 h after gemfibrozil). Thus, a strong CYP2C8 inhibitory effect persisted even after gemfibrozil and gemfibrozil 1-O-beta-glucuronide concentrations had decreased to less than 1% of their maximum (24-h dosing interval). In addition, the metabolite to repaglinide AUC ratios indicated that significant (P < 0.05) inhibition of repaglinide metabolism continued up to 48 h after gemfibrozil administration. Based on the recovery of repaglinide oral clearance, the in vivo turnover half-life of CYP2C8 was estimated to average 22 +/- 6 h (mean +/- S.D.). In summary, CYP2C8 activity is recovered gradually during days 1 to 4 after gemfibrozil discontinuation, which should be considered when CYP2C8 substrate dosing is planned. The estimated CYP2C8 half-life will be useful for in vitro-in vivo extrapolations of drug-drug interactions involving induction or mechanism-based inhibition of CYP2C8.

Topics: Administration, Oral; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Biotransformation; Blood Glucose; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP2C8; Drug Interactions; Enzyme Inhibitors; Female; Gemfibrozil; Genotype; Glucuronates; Half-Life; Humans; Hypoglycemic Agents; Hypolipidemic Agents; Liver-Specific Organic Anion Transporter 1; Male; Models, Biological; Molecular Probes; Organic Anion Transporters; Phenotype; Piperidines; Young Adult

To study the effect of insulin treatment in combination with metformin or an insulin secretagogue, repaglinide, on glycaemic regulation in non-obese patients with type 2 diabetes.. Randomised, double blind, double dummy, parallel trial.. Secondary care in Denmark between 2003 and 2006.. Non-obese patients (BMI

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Aspart; Male; Metformin; Middle Aged; Patient Compliance; Piperidines; Treatment Outcome; Weight Gain

Repaglinide and metformin enhance insulin secretion and decrease hepatic gluconeogenesis, respectively, and are commonly coadministered as separate formulations to treat patients with type 2 diabetes mellitus. A single combination therapy tablet offers increased patient convenience and the subsequent potential for increased therapy compliance. The aim of this randomized, single-blind, three-period crossover study was to determine the bioequivalence of a fixed-dose combination (FDC) tablet of repaglinide/metformin 2 mg/500 mg versus repaglinide 2 mg and metformin 500 mg coadministered as separate formulations. Secondary objectives included a comparison of the dose proportionality of an FDC tablet of repaglinide/metformin 1 mg/500 mg and an FDC tablet of repaglinide/metformin 2 mg/500 mg, as well as the safety and tolerability of repaglinide and metformin in combination tablet therapy.. Healthy subjects (n = 93, age 18-45 years) were randomized to one of six possible treatment sequences (Williams design) of an FDC tablet of repaglinide/metformin 2 mg/500 mg, repaglinide 2 mg and metformin 500 mg coadministered as separate tablets and an FDC of repaglinide/metformin 1 mg/500 mg. Fifty-five subjects completed the study. Four primary pharmacokinetic endpoints (area under the plasma concentration-time curve [AUC] from time 0 hours to infinity; AUC from time 0 to 24 hours; AUC from time 0 hours to time t [the last time of measurable concentration after dosing]; and the maximum plasma concentration) were used to assess bioequivalence and dose proportionality. The safety and tolerability of repaglinide and metformin in combination tablet therapy were also evaluated.. Both repaglinide and metformin in the combination tablet were determined to be bioequivalent to the individual tablets of repaglinide 2 mg and metformin 500 mg, as the limits of the 90% confidence interval of the mean treatment ratio for all pharmacokinetic parameters were contained within the pre-specified interval required for bioequivalence (0.8, 1.25). Additionally, an FDC tablet of repaglinide/metformin 2 mg/500 mg was determined to be dose proportional to an FDC of repaglinide/metformin 1 mg/500 mg for all analysed endpoints. No withdrawals as a result of adverse events occurred during this study. In addition, no clinically relevant abnormalities were found during physical examinations, in vital signs, ECG parameters or clinical laboratory parameters.. An FDC tablet of repaglinide/metformin 2 mg/500 mg was bioequivalent to individual tablets of repaglinide 2 mg and metformin 500 mg. Additionally, an FDC tablet of repaglinide/metformin 2 mg/500 mg was dose proportional to an FDC tablet of repaglinide/metformin 1 mg/500 mg. Finally, no unexpected safety concerns were noted with repaglinide/metformin combination tablet therapy. Our results suggest that FDC tablets of repaglinide and metformin would provide safety and efficacy comparable to that of repaglinide and metformin administered as separate formulations.

Topics: Adolescent; Adult; Area Under Curve; Carbamates; Cross-Over Studies; Drug Combinations; Drug Therapy, Combination; Female; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Sample Size; Single-Blind Method; Therapeutic Equivalency; Young Adult

Organic anion transporting polypeptide 1B1 (OATP1B1), encoded by SLCO1B1, is an influx transporter expressed on the sinusoidal membrane of human hepatocytes. The aim of this study was to investigate whether the SLCO1B1*1B haplotype affects the pharmacokinetics and pharmacodynamics of repaglinide and nateglinide.. Eight healthy volunteers with the SLCO1B1*1B/*1B genotype and 16 with the SLCO1B1*1A/*1A genotype ingested a single 0.5-mg dose of repaglinide and, after a washout period of 1 week, a single 60-mg dose of nateglinide. Plasma repaglinide and nateglinide and blood glucose concentrations were measured for 7 h.. The AUC(0-infinity) and Cmax of repaglinide were 32% (P=0.007) and 24% lower (P=0.056) in the individuals with the SLCO1B1*1B/*1B genotype than in those with the SLCO1B1*1A/*1A genotype. The mean blood glucose concentration from 0 to 7 h after repaglinide intake was 10% higher in the SLCO1B1*1B/*1B participants than in the SLCO1B1*1A/*1A participants (P=0.007). The Cmax of nateglinide occurred earlier in the SLCO1B1*1B/*1B participants than in the SLCO1B1*1A/*1A participants (P=0.004), but no differences were seen in the other pharmacokinetic variables of nateglinide.. The SLCO1B1*1B/*1B genotype is associated with reduced plasma concentrations of repaglinide, consistent with an enhanced hepatic uptake by OATP1B1, but has limited effects on the pharmacokinetics of nateglinide.

Topics: Administration, Oral; Adult; Area Under Curve; Blood Glucose; Carbamates; Cyclohexanes; Female; Haplotypes; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Male; Nateglinide; Organic Anion Transporters; Phenylalanine; Piperidines; Time Factors

In a randomized crossover study, 24 SLCO181-genotyped healthy volunteers were given daily doses of 1,200 mg gemfibrozil, 40 mg atorvastatin, or placebo, followed by 0.25 mg of repaglinide on day 3. The mean increase in the repaglinide area under the plasma concentration-time curve from 0 h to infinity (AUC(0-infinity)) produced by gemfibrozil was larger in individuals with the SLCO1B1 c.521CC genotype (n = 6) than in those with the c.521TC (n = 6) and c.521TT (n = 12) genotypes, by factors of 1.56 (P = 0.004) and 1.54 (P = 0.002), respectively. Gemfibrozil prolonged the repaglinide elimination half-life 1.43 times more in the c.521 CC group than in the c.521TT group (P = 0.047), but no differences were seen in the effects on peak plasma concentration (C(max)). While on gemfibrozil, the minimum blood glucose concentration after repaglinide intake was 19% lower in the c.521CC participants than in the c.521TT participants (P = 0.009). In the c.521TT group, atorvastatin intake had the effect of increasing repaglinide Cmax and AUC(0-infinity) by41% (P = 0.001) and 18% (P = 0.033), respectively. In conclusion, the extent of gemfibrozil-repaglinide interaction depends on SLCO1B1 genotype. Atorvastatin raises plasma repaglinide concentrations, probably by inhibiting organic anion transporting polypeptide 1B1 (OATP1B1).

Topics: Administration, Oral; Adult; Area Under Curve; Atorvastatin; Blood Glucose; Carbamates; Cross-Over Studies; Drug Interactions; Female; Gemfibrozil; Genotype; Half-Life; Heptanoic Acids; Humans; Hypoglycemic Agents; Hypolipidemic Agents; Liver-Specific Organic Anion Transporter 1; Male; Organic Anion Transporters; Piperidines; Polymorphism, Genetic; Pyrroles

To evaluate the efficacy and safety of the association of repaglinide, metformin and bedtime NPH insulin compared to two classic regimens: metformin plus NPH and two doses of NPH in patients with poorly controlled type 2 diabetes despite two or more oral antidiabetic drugs (OADs).. Random, parallel and open study of 24 weeks with 37 patients randomized into three therapeutic groups: group A (n=12) (repaglinide/metformin/NPH), group B (n=12) (metformin/NPH) and group C (n=13) (NPH/NPH). The insulin was adjusted in the visits to obtain a basal blood glucose <110 mg/dl. The endpoint criteria included HbA1c, blood glucose profile, hypoglycemias and body weight.. At the end of the study, group A presented HbA1c (mean+/-standard deviation) 7.2+/-0.7%, which was significantly less than B (8.8+/-0.1%) and C (8.4+/-1.2%). In terms of absolute reduction, there were only differences (p=0.01) between group A (-2.4+/-1.1%) and B (-0.7+/-1.2%). Group A presented lower postprandial blood glucose values (p<0.01). Nor were there any significant differences in weight gain and incidence of hypoglycemia.. The combination of repaglinide, metformin and bedtime NPH is safe and effective and it provides better postprandial blood glucose control. The association of metformin and a dose of NPH does not obtain suitable control in patients with a long evolution who have already received two or more OADs.

Topics: Aged; Blood Glucose; Blood Pressure; Body Mass Index; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Insulin, Isophane; Male; Metformin; Middle Aged; Piperidines; Prospective Studies; Safety; Weight Gain

Non-obese patients with type 2 diabetes (T2DM) are characterized by predominant defective insulin secretion. However, in non-obese T2DM patients, metformin, targeting insulin resistance, is non-inferior to the prandial insulin secretagogue, repaglinide, controlling overall glycaemia (HbA1c). Whether the same apply for postprandial glucose and lipid metabolism is unknown. Here, we compared the effect of metformin versus repaglinide on postprandial metabolism in non-obese T2DM patients.. Single-centre, double-masked, double-dummy, crossover study during 2x4 months involving 96 non-obese (body mass index < or = 27 kg/m2) insulin-naïve T2DM patients. At enrolment, patients stopped prior oral hypoglycaemic agents therapies and after a 1-month run-in period on diet-only treatment, patients were randomized to repaglinide (2 mg) thrice daily followed by metformin (1 g) twice daily or vice versa each during 4 months with 1-month washout between interventions.. Postprandial metabolism was evaluated by a standard test meal (3515 kJ; 54% fat, 13% protein and 33% carbohydrate) with blood sampling 0-6 h postprandially.. Fasting levels and total area under the curve (AUC) for plasma glucose, triglycerides and free fatty acids (FFA) changed equally between treatments. In contrast, fasting levels and AUC of total cholesterol, low-density lipoprotein (LDL) cholesterol, non-high-density lipoprotein (non-HDL) cholesterol and serum insulin were lower during metformin than repaglinide (mean (95% confidence intervals), LDL cholesterol difference metformin versus repaglinide: AUC: -0.17 mmol/l (-0.26; -0.08)). AUC differences remained significant after adjusting for fasting levels.. In non-obese T2DM patients, metformin reduced postprandial levels of glycaemia, triglycerides and FFA similarly compared to the prandial insulin secretagogue, repaglinide. Furthermore, metformin reduced fasting and postprandial cholesterolaemia and insulinaemia compared with repaglinide. These data support prescription of metformin as the preferred drug in non-obese patients with T2DM targeting fasting and postprandial glucose and lipid metabolism.

Topics: Aged; Area Under Curve; Blood Glucose; Carbamates; Cholesterol; Cholesterol, LDL; Cross-Over Studies; Diabetes Mellitus, Type 2; Double-Blind Method; Fasting; Fatty Acids, Nonesterified; Female; Humans; Hypoglycemic Agents; Insulin; Lipids; Male; Metformin; Middle Aged; Piperidines; Postprandial Period; Triglycerides

Glycemic control in elderly persons with type 2 diabetes mellitus (T2DM) is challenging because they are more likely to have other age-associated medical conditions and to experience hypoglycemia during intensive therapy. A best therapeutic strategy for these patients has not yet been defined. We investigated the efficacy and safety of adding once-daily insulin glargine to patients' current oral antidiabetic drugs (OAD) regimen, compared to increasing the OAD doses. The study enrolled patients aged 65 years or more, with poor glycemic control. Patients were randomized to two groups and entered a 3-week titration period in which their actual therapy was adjusted to meet the study's glycemic goals, by either adding insulin glargine to current therapy (group A, 27 patients) or increasing current OAD dosages (group B, 28 patients). Thereafter, therapies were continued unchanged for a 24-week observation period. The mean therapeutic dosage of insulin glargine in group A was 14.9 IU/day (SD = 5.0 IU/day). During the observation period, mean levels of glycosylated hemoglobin (HbA1c) reduced by 1.5% in group A and 0.6% in group B (P = 0.381). An HbA1c level <7.0% was achieved by five patients in each group. Mean fasting blood glucose levels reduced by 29 and 15% in groups A and B, respectively (P = 0.029). Group A had fewer total hypoglycemic events (23 vs. 79, P = 0.030) and fewer patients experiencing any such event (9 vs. 17, P = 0.045). Neither a serious hypoglycemic event nor other adverse event occurred. These results suggest that, compared to increasing OAD dosage, the addition of insulin glargine to current OAD therapy is as effective but safer in terms of the risk for hypoglycemia in elderly patients with T2DM.

Topics: Administration, Oral; Aged; Blood Glucose; Body Mass Index; Carbamates; Drug Therapy, Combination; Female; Gliclazide; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Glargine; Insulin, Long-Acting; Male; Metformin; Pioglitazone; Piperidines; Research Design; Rosiglitazone; Thiazolidinediones

Thirty-two healthy volunteers with different SLCO1B1 genotypes ingested a 0.5-mg dose of repaglinide and 60-mg dose of nateglinide with a washout period of 1 week. Participants with SLCO1B1 c.521CC genotype (n = 4) had a 59% (P = 0.001) or 72% (P < 0.001) greater mean area under the plasma repaglinide concentration-time curve (AUC(0-infinity)) than participants with c.521TC (n = 12) or c.521TT (n = 16) genotypes. The AUC(0-infinity) of repaglinide metabolites M2 and M4 were 112% (P = 0.004) and 81% (P = 0.002) larger in participants with c.521CC genotype than in those with c.521TT genotype, but no differences existed in the pharmacokinetics of M1. Maximum decrease in blood glucose concentration correlated with repaglinide AUC(0-infinity) (r = 0.412, P = 0.019). SLCO1B1 polymorphism had no significant effect on the pharmacokinetics or pharmacodynamics of nateglinide or its M7 metabolite. Thus, in contrast to repaglinide, the disposition of nateglinide is unaffected by the SLCO1B1 c.521T>C polymorphism.

Topics: Analysis of Variance; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Blood Glucose; Carbamates; Chromatography, Liquid; Cyclohexanes; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP2C9; Dose-Response Relationship, Drug; Genotype; Half-Life; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Metabolic Clearance Rate; Molecular Structure; Nateglinide; Organic Anion Transporters; Pharmacogenetics; Phenylalanine; Piperidines; Polymorphism, Single Nucleotide; Tablets; Tandem Mass Spectrometry

Repaglinide is metabolized by cytochrome P450 (CYP) 2C8 and 3A4. Gemfibrozil has the effect of increasing the area under the concentration-time curve (AUC) of repaglinide eightfold. We studied the effect of dosing interval on the extent of the gemfibrozil-repaglinide interaction. In a randomized five-phase crossover study, 10 healthy volunteers ingested 0.25 mg repaglinide, with or without gemfibrozil pretreatment. Plasma repaglinide, gemfibrozil, their metabolites, and blood glucose were measured. When the last dose of 600 mg gemfibrozil was ingested simultaneously with repaglinide, or 3, 6, or 12 h before, it increased the AUC(0-infinity) of repaglinide 7.0-, 6.5-, 6.2- and 5.0-fold, respectively (P < 0.001). The peak repaglinide concentration increased approximately twofold (P < 0.001), and the half-life was prolonged from 1.2 h to 2-3 h (P < 0.001) during all the gemfibrozil phases. The drug interaction effects persisted at least 12 h after gemfibrozil was administered, although plasma gemfibrozil and gemfibrozil 1-O-beta-glucuronide concentrations were only 5 and 10% of their peak values, respectively. The long-lasting interaction is likely caused by mechanism-based inhibition of CYP2C8 by gemfibrozil glucuronide.

Topics: Adult; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Blood Glucose; Carbamates; Cytochrome P-450 CYP2C8; Drug Interactions; Female; Gemfibrozil; Glucuronates; Half-Life; Humans; Hypoglycemic Agents; Hypolipidemic Agents; Male; Piperidines

In patients with type 2 diabetes mellitus (T2DM), biomarkers reflecting inflammation and endothelial dysfunction have been linked to cardiovascular disease (CVD biomarkers) and metabolic regulation. In T2DM patients, metformin and insulin secretagogues have demonstrated equal anti-hyperglycaemic potency. Here, we report the effect of metformin versus an insulin secretagogue, repaglinide, on CVD biomarkers in non-obese T2DM patients.. Single-centre, double-masked, double-dummy, crossover study during 2x4 months involving 96 non-obese (body mass index< or =27 kg/m(2)) insulin-naïve T2DM patients. At enrolment, previous oral hypoglycaemic agents were stopped and the patients entered a 1-month run-in on diet-only treatment. Hereafter, patients were randomized to either 2 mg repaglinide thrice daily followed by 1 g metformin twice daily or vice versa each during 4 months with a 1-month washout between interventions.. Levels of tumour necrosis factor-alpha, plasminogen activator inhibitor-1 antigen, tissue-type plasminogen activator antigen, von Willebrand factor, soluble intercellular adhesion molecule-1 and soluble E-selectin were significantly lower during metformin versus repaglinide treatments. In contrast, Amadori albumin and heart rate were higher during metformin versus repaglinide. Levels of interleukin-6, fibrinogen, soluble vascular cell adhesion molecule-1, asymmetric dimethylarginine and advanced glycation end products as well as glycaemic levels (previously reported) and 24-h blood pressure were similar between treatments. Adjustment for known macrovascular disease did not affect the between-treatment effects.. In non-obese T2DM patients, metformin was more effective in reducing selected biomarkers reflecting inflammation and endothelial dysfunction compared with repaglinide despite similar glycaemic levels between treatments.

Topics: Aged; Blood Glucose; Body Weight; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Endothelium, Vascular; Female; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Risk Factors; Treatment Outcome; Vasculitis

Ischemic preconditioning is an increased tolerance to myocardial ischemia during the second of two consecutive exercise tests. ATP-sensitive K(+) channel blockers, such as glinides and sulfonylurea drugs, can induce loss of ischemic preconditioning. This study aimed to investigate the effects of repaglinide, a hypoglycemic agent with an affinity for myocardial ATP-sensitive K (+)channels, on the results of consecutive exercise tests in patients with diabetes and multivessel coronary artery disease.. Forty-two patients with type 2 diabetes and chronic stable angina pectoris, and two-vessel or three-vessel disease participated in this study. The patients underwent two consecutive treadmill exercise tests (phase 1). On the day after these exercise tests, 2 mg of oral repaglinide was given to the patients. One week later, two exercise tests were repeated consecutively (phase 2).. All patients achieved 1.0-mm ST-segment depression during the four exercise tests (T1, T2, T3, and T4). In phase 2, seven patients improved in time to onset of 1.0-mm ST-segment depression. The worsening of the time to onset of 1.0-mm ST-segment depression in phase 2 demonstrated ischemic preconditioning block in 83.3% of patients (P=0.0001). Even the postexercise electrocardiographic parameters (ST-segment depression morphology and magnitude and arrhythmias) were significantly different between the groups with and without pharmacologic ischemic preconditioning block (P=0.031).. Repaglinide, an oral hypoglycemic agent with ATP-sensitive K(+) channel-blocker activity, eliminated the myocardial ischemic preconditioning in patients with coronary disease and diabetes.

Topics: Angina Pectoris; Carbamates; Diabetes Mellitus, Type 2; Electrocardiography; Exercise Test; Female; Humans; Hypoglycemic Agents; Ischemic Preconditioning, Myocardial; Male; Middle Aged; Piperidines; Time Factors

Treatment with K-ATP channel openers, such as diazoxide, can have beneficial effects on insulin secretion in both Type 1 and Type 2 diabetes. However, the precise conditions for obtaining beneficial effects without untoward events have not been determined. We tested the hypothesis that intermittent administration of diazoxide at bedtime for 12 weeks could produce beneficial effects in the absence of side-effects in Type 2 diabetic patients who were not taking insulin.. After an 8-week run-in period, during which treatment with repaglinide and metformin was optimized, we randomized 26 patients to either diazoxide, 100 mg at bedtime, or placebo.. Side-effects were absent or minimal. HbA(1c) did not change. However day-time glucose concentrations by home glucose monitoring were approximately 1.5 mmol/l higher with diazoxide vs. placebo. Stimulation tests (C-peptide-glucagon and breakfast) did not indicate improved pancreatic B-cell function, except by posthoc analysis, in a subgroup of younger age.. Compared with previous results with diazoxide together with bedtime insulin, the present results are less favourable and indicate that concomitant insulin treatment is needed during intervention with K-ATP channel openers.

Topics: Carbamates; Diabetes Mellitus, Type 2; Diazoxide; Dose-Response Relationship, Drug; Female; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Insulin-Secreting Cells; Male; Metformin; Middle Aged; Piperidines; Treatment Outcome

Metformin is the 'drug-of-first-choice' in obese patients with type 2 diabetes mellitus (T2DM) due to its antihyperglycaemic and cardiovascular protective potentials. In non-obese patients with T2DM, insulin secretagogues are empirically used as first choice. In this investigator-initiated trial, we evaluated the effect of metformin vs. an insulin secretagogue, repaglinide on glycaemic regulation and markers of inflammation and insulin sensitivity in non-obese patients with T2DM.. A single-centre, double-masked, double-dummy, crossover study during 2 x 4 months involved 96 non-obese (body mass index < or = 27 kg/m(2)) insulin-naïve patients with T2DM. At enrolment, previous oral hypoglycaemic agents (OHA) were stopped and patients entered a 1-month run-in on diet-only treatment. Hereafter, patients were randomized to either repaglinide 2 mg thrice daily followed by metformin 1 g twice daily or vice versa each during 4 months with 1-month washout between interventions.. End-of-treatment levels of haemoglobin A(1c) (HbA(1c)), fasting plasma glucose, mean of seven-point home-monitored plasma glucose and fasting levels of high-sensitivity C-reactive protein and adiponectin were not significantly different between treatments. However, body weight, waist circumference, fasting serum levels of insulin and C-peptide were lower and less number of patients experienced hypoglycaemia during treatment with metformin vs. repaglinide. Both drugs were well tolerated.. In non-obese patients with T2DM, overall glycaemic regulation was equivalent with less hypoglycaemia during metformin vs. repaglinide treatment for 2 x 4 months. Metformin was more effective targeting non-glycaemic cardiovascular risk markers related to total and abdominal body fat stores as well as fasting insulinaemia. These findings may suggest the use of metformin as the preferred OHA also in non-obese patients with T2DM.

Topics: Adiponectin; Biomarkers; Blood Glucose; Body Weight; C-Peptide; C-Reactive Protein; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Male; Metformin; Middle Aged; Patient Compliance; Piperidines; Prospective Studies; Waist-Hip Ratio

To compare combination use of repaglinide, metformin and bedtime Neutral Protamine Hagedorn (NPH) insulin with conventional approaches of insulin initiation in patients with Type 2 diabetes (T2DM).. Eighty-two patients with T2DM with suboptimal glycaemic control on oral glucose-lowering agents were randomized to one of three treatment regimens for 4 months. Group 1 received metformin and twice daily biphasic 30/70 human insulin mixture (n = 27), group 2 metformin and bedtime NPH insulin (n = 26) and group 3 metformin, bedtime NPH insulin and mealtime repaglinide (n = 25).. Seventy-five patients completed the study. Baseline and end-point mean HbA1c levels fell from 9.0 +/- 1.1 to 7.9 +/- 1.1% in group 1, 10.0 +/- 2.2 to 9.2 +/- 1.4% group 2 and 10.0 +/- 1.7 to 8.1 +/- 1.5% in group 3, respectively. All groups showed improvements in HbA1c. There was no significant difference between groups in the proportions of patients experiencing hypoglycaemia (29.6, 25.0 and 16.7%, respectively; P = 0.55) or in mean weight gain (2.9, 0.7 and 2.2 kg, respectively; P = 0.06). By 4 months, insulin doses were 0.63 +/- 0.32 IU/kg in group 1, 0.58 +/- 0.21 IU/kg in group 2 and 0.37 +/- 0.22 IU/kg in group 3 (group 3 vs. groups 1 and 2: P < 0.002).. The approach using repaglinide, metformin and NPH insulin improved glycaemic control with a similar safety profile to conventional insulin initiation in T2DM and produced final glycaemic control similar to metformin and a twice daily biphasic insulin mixture.

Topics: Adult; Aged; Aged, 80 and over; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Drug Therapy, Combination; Female; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin, Isophane; Male; Metformin; Middle Aged; Piperidines; Treatment Outcome; Weight Gain

To evaluate the efficacy of nateglinide vs. repaglinide in blood glucose (BG) control and the effect on insulin resistance and beta-Cell function in patients with type 2 diabetes.. A randomized controlled double-blind and double-dummy multicentre clinical trial was conducted. A total of 230 Chinese patients with type 2 diabetes were enrolled in five clinical centres. The patients were divided randomly into group A [repaglinide 1.0 mg three times daily (t.i.d.), n = 115] or group B (nateglinide 90 mg t.i.d., n = 115). At baseline and end of the 12-week clinical trial, standard mixed meal tolerance tests were performed.. A total of 223 patients (96.9%) completed the trial. There was no significant difference between repaglinide and nateglinide groups in the effects of reducing fasting blood glucose (FBG), 30-, 60- and 120-min BG during 12 weeks (p > 0.05). At week 12, no significant difference was shown between the two groups in BG or haemoglobin A(1c) (HbA(1c)) (p > 0.05). However, the effect on HbA(1c) in repaglinide group was stronger than that in nateglinide group (p < 0.05). After 12-week treatment, area under the curve (AUC) of BG decreased (p < 0.05), and AUC of insulin and C-peptide (CP) increased in both groups (p < 0.05). The effects of nateglinide on AUC of BG, insulin and CP were similar to that of repaglinide (p > 0.05). There was no significant difference between the two groups in AUC of BG, insulin or CP in week 12 (p > 0.05). Furthermore, homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function indexes measured by HOMA-beta, DeltaI(30)/DeltaG(30) and (DeltaI(30)/DeltaG(30))/HOMA-IR were improved significantly in both groups during 12 weeks (p < 0.05). The effects of improving HOMA-IR and beta-cell function indexes in nateglinide group were comparable with that of repaglinide group (p > 0.05).. The efficacy of repaglinide and nateglinide in FBG, postprandial glucose excursion and early-phase insulin secretion is similar. But the effect of repaglinide 1.0 mg t.i.d. on HbA(1c) is stronger than that of nateglinide 90 mg t.i.d.. This trial had shown that nateglinide and repaglinide could comparably improve insulin sensitivity and beta-cell function.

Topics: Adult; Age of Onset; Aged; Area Under Curve; Asian People; Blood Glucose; Carbamates; China; Cyclohexanes; Diabetes Mellitus, Type 2; Double-Blind Method; Humans; Insulin; Insulin Secretion; Insulin-Secreting Cells; Middle Aged; Nateglinide; Phenylalanine; Piperidines

The primary aim of the study was to investigate the possible effect of the CYP2C8*3 allele and of grapefruit juice on the pharmacokinetics of repaglinide. Furthermore, the impact of a single dose of grapefruit juice on the pharmacokinetics of repaglinide in relation to dose.. Thirty-six healthy male subjects, genotyped for CYP2C8*3 (11 genotyped as CYP2C8*1/*3, one as CYP2C8*3/*3 and 24 as CYP2C8*1/*1), participated in a randomized, cross-over trial. In the two phases, the subjects drank 300 mL water or 300 mL grapefruit juice, in randomized order, 2 h before administration of a single dose of either 0.25 mg or 2 mg repaglinide.. Neither the mean AUC(0-infinity) (geometric mean ratio: 1.01; 95% CI: 0.93-1.1, P = 0.88) nor the mean C(max) (geometric mean ratio: 1.05; 95% CI: 0.94-1.2, P = 0.35) of repaglinide were statistically significantly different in the group carrying the CYP2C8*3 mutant allele compared with wild-types. Grapefruit juice caused a 19% decrease in the geometric mean ratio of the 3-hydroxyquinidine to quinidine ratio (difference: 0.81; 95% CI: 0.75-0.87, P < 0.0001), which was used as an index of CYP3A4 activity, and an increase in the mean AUC(0-infinity) of repaglinide (geometric mean ratio: 1.13; 95% CI: 1.04-1.2, P = 0.0048), but had no statistically significant effect on the t(1/2). There was no statistically significant difference in blood glucose concentration in subjects who had or had not ingested grapefruit juice. The effect was more pronounced at the low dose of repaglinide (0.25 mg) than at the therapeutic dose of 2 mg.. The pharmacokinetics of repaglinide in subjects carrying the CYP2C8*3 mutant allele did not differ significantly from those in the wild-types. Grapefruit juice increased the bioavailability of repaglinide, suggesting significant intestinal elimination of the drug which was assumed to be primarily mediated by CYP3A4 in the gut.

Topics: Administration, Oral; Adult; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Beverages; Blood Glucose; Carbamates; Citrus paradisi; Cross-Over Studies; Cytochrome P-450 CYP2C8; Genotype; Humans; Hypoglycemic Agents; Male; Piperidines; Polymorphism, Genetic; Quinidine

To compare the effects of treatment with repaglinide and glibenclamide on platelet function and endothelial markers in patients with Type 2 diabetes mellitus, before and after a standardized meal.. Fifteen patients with Type 2 diabetes were investigated on three occasions: at baseline without oral hypoglycaemic drug treatment, and after 6 weeks' treatment with repaglinide or glibenclamide, respectively, in an open randomized cross-over study. Agonist-induced platelet P-selectin expression and platelet aggregation, urinary thromboxane, soluble P-selectin, von Willebrand factor (VWF), soluble E-selectin, intercellular adhesion molecule (ICAM-1) and C-reactive protein (CRP) were measured. In addition, pre-meal data were compared with non-diabetic control subjects (n = 15), matched for sex, age and BMI.. Adenosine diphosphate (ADP)-induced platelet P-selectin expression increased post-meal in Type 2 diabetic patients both at baseline and after treatment with repaglinide and glibenclamide (P < 0.01 for all; repeated measures anova). Repaglinide treatment reduced fasting ADP-induced P-selectin expression compared with baseline (P = 0.01), but did not influence meal-induced platelet hyper-reactivity (P = 0.32). No significant anti-platelet effects of glibenclamide treatment were found. Plasma concentrations of VWF and ICAM-1 were elevated in patients with Type 2 diabetes compared with control subjects (P < 0.05 for both) and were reduced during treatment with repaglinide (P < 0.01 for both) but did not change during glibenclamide treatment.. The post-meal state is associated with enhanced platelet reactivity in patients with Type 2 diabetes mellitus. Pre-meal treatment with repaglinide or glibenclamide does not inhibit postprandial platelet activation, but repaglinide treatment is associated with attenuated platelet and endothelial activity in the fasting state.

Topics: Adenosine Diphosphate; Blood Glucose; C-Reactive Protein; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Eating; Fasting; Female; Glyburide; Humans; Hypoglycemic Agents; Insulin; Intercellular Adhesion Molecule-1; Male; Middle Aged; P-Selectin; Piperidines; Platelet Activation; Platelet Function Tests; Postprandial Period; Treatment Outcome; von Willebrand Factor

Pioglitazone, a thiazolidinedione antidiabetic, inhibits cytochrome P450 (CYP) 2C8 and CYP3A4 enzymes in vitro. Repaglinide, a meglitinide analogue antidiabetic, is metabolised by CYP2C8 and CYP3A4. In patients with type 2 diabetes, the pioglitazone-repaglinide combination has acted synergistically on glycaemic parameters. Our aim was to determine whether pioglitazone increases the plasma concentrations of repaglinide.. In a randomized, 2-phase cross-over study, 12 healthy volunteers received 30 mg pioglitazone or placebo once daily for 5 days. On day 5, they ingested a single 0.25 mg dose of repaglinide 1 h after the last pretreatment dose. Plasma repaglinide and pioglitazone, and blood glucose concentrations were measured for 12 h.. During the pioglitazone phase, the mean peak plasma repaglinide concentration (C(max)) and the total area under the concentration-time curve [AUC(0-infinity)] of repaglinide were 100% (range 53-157%, P=0.99) and 90% (range 63-120%, P=0.22), respectively, of those during the placebo phase. Also the half-life of repaglinide was unaffected, but the median peak time of repaglinide was shortened from 40 min to 20 min by pioglitazone (P=0.014). The short-term pioglitazone administration did not modify the blood glucose-lowering effect of a single dose of repaglinide.. Pioglitazone does not increase the plasma concentrations of repaglinide, indicating that the inhibitory effect of pioglitazone on CYP2C8 and CYP3A4 is very weak in vivo, probably due to its extensive plasma protein binding. The synergistic effect of repaglinide and pioglitazone on the glycaemic parameters, seen in patients with type 2 diabetes during their long-term use, is unlikely to be caused by inhibition of repaglinide metabolism by pioglitazone.

Topics: Administration, Oral; Adult; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Blood Glucose; Capsules; Carbamates; Chromatography, Liquid; Cross-Over Studies; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drug Administration Schedule; Enzyme Inhibitors; Female; Gas Chromatography-Mass Spectrometry; Half-Life; Humans; Hypoglycemic Agents; In Vitro Techniques; Male; Pioglitazone; Piperidines; Substrate Specificity; Thiazolidinediones

The antidiabetic repaglinide is metabolized by cytochrome P450 (CYP) 2C8 and CYP3A4. Telithromycin, an antimicrobial agent, inhibits CYP3A4 in vitro and in vivo. Montelukast, an antiasthmatic drug, is a potent inhibitor of CYP2C8 in vitro. We studied the effects of telithromycin, montelukast, and the combination of telithromycin and montelukast on the pharmacokinetics and pharmacodynamics of repaglinide.. In a randomized 4-phase crossover study, 12 healthy volunteers received 800 mg telithromycin, 10 mg montelukast, both telithromycin and montelukast, or placebo once daily for 3 days. On day 3, they ingested a single 0.25-mg dose of repaglinide. Plasma and urine concentrations of repaglinide and its metabolites M1, M2, and M4, as well as blood glucose concentrations, were measured for 12 hours.. Telithromycin alone raised the mean peak plasma repaglinide concentration to 138% (range, 91%-209%; P = .006) and the total area under the plasma concentration-time curve from 0 hours to infinity [AUC0-infinity] of repaglinide to 177% (range, 125%-257%; P < .001) of control (placebo). Telithromycin reduced the AUC0-infinity ratio of the metabolite M1 to repaglinide by 68% (P < .001) and the urinary excretion ratio of M1 to repaglinide by 77% (P = .001). In contrast to previous estimates based on in vitro CYP2C8 inhibition data, montelukast had no significant effect on the pharmacokinetics of repaglinide or its metabolites and did not significantly alter the effect of telithromycin on repaglinide pharmacokinetics. Telithromycin, unlike montelukast, lowered the maximum blood glucose concentration (P = .002) and mean blood glucose concentration from 0 to 3 hours (P = .008) after repaglinide intake, as compared with placebo.. Telithromycin increases the plasma concentrations and blood glucose-lowering effect of repaglinide by inhibiting its CYP3A4-catalyzed biotransformation and may increase the risk of hypoglycemia. Unexpectedly, montelukast has no significant effect on repaglinide pharmacokinetics, suggesting that it does not significantly inhibit CYP2C8 in vivo. The low free fraction of montelukast in plasma may explain the lack of effect on CYP2C8 in vivo, despite the low in vitro inhibition constant, highlighting the importance of incorporating plasma protein binding to interaction predictions.

Topics: Acetates; Adolescent; Adult; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Biotransformation; Blood Glucose; Carbamates; Cross-Over Studies; Cyclopropanes; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Drug Interactions; Female; Humans; Hypoglycemic Agents; Ketolides; Leukotriene Antagonists; Male; Piperidines; Quinolines; Sulfides

The purpose of this study was to investigate the use of the short-acting insulin secretion drug repaglinide in new-onset diabetes mellitus (NODM) after renal transplantation. Twenty-three Caucasian patients with NODM after renal transplantation were selected to receive repaglinide therapy and were followed for at least 6 months. A control group treated with rosiglitazone was chosen for comparison. Successful repaglinide treatment was defined as a significant improvement of blood glucose concentrations and HbA1c <7% in the absence of glucosuria and without the need for the addition of further anti-diabetic agents. After 6 months of treatment with repaglinide, 14 of the 23 patients were successfully treated. Mean HbA1c decreased from 7.6 +/- 0.6% to 5.8 +/- 0.6% in 14 patients treated successfully. In nine patients, hyperglycemia persisted, and they were switched to insulin treatment (HbA1c 8.5 +/- 2.9% at the beginning to 7.4 +/- 2.2%). Mean serum creatinine levels, cyclosporine A and tacrolimus blood levels did not change significantly following institution of repaglinide therapy. The rate of successful treatment and the degree of HbA1c decrease were similar compared to rosiglitazone-treated control patients. The data from our observational study indicate that repaglinide can be an effective treatment option in Caucasian patients with NODM after renal transplantation.

Topics: Carbamates; Diabetes Mellitus; Female; Humans; Hypoglycemic Agents; Kidney Transplantation; Male; Middle Aged; Piperidines; Rosiglitazone; Thiazolidinediones; Treatment Outcome

Impaired glucose tolerance (IGT) is associated with increased cardiovascular risk. The pathophysiological mechanisms linking post-challenge hyperglycemia to accelerated atherosclerosis, however remain to be elucidated.. A prospective, open, randomised, cross-over study was performed to investigate the effect of 2 mg repaglinide on hyperglycemia and endothelial function during an oral glucose tolerance test (75 g glucose) in 12 subjects with diagnosed IGT. Blood samples for determination of plasma glucose were drawn fasting, 1 and 2 hours after glucose ingestion. Endothelial function was assessed by measuring flow-mediated dilatation (FMD) of the brachial artery with high-resolution ultrasound.. Administration of repaglinide resulted in a significant reduction of plasma glucose at 2 hours (172.8+/-48.4 vs. 138.3+/-41.2 mg/dl; p < 0.001). The flow-mediated dilatation (FMD) 2 hours after the glucose-load was significantly reduced in comparison to fasting in the control group (6.21+/-2.69 vs. 7.98+/-2.24 %; p = 0.028), whereas after theadministration of repaglinide the FMD was not significantly different to fasting values (7.24+/-2.57 vs. 8.18+/-2.93 %; p = n.s.). Linear and logistic regression analysis revealed that only the change of glucose was significantly correlated to the change of FMD observed (p < 0.001). Regression analysis after grouping for treatment and time confirmed the strong negative association of the changes of plasma glucose and FMD and indicate that the effect of repaglinide observed is based on the reduction glycemia.. In subjects with IGT, the endothelial dysfunction observed after a glucose challenge is related to the extent of hyperglycemia. Reduction of hyperglycemia by repaglinide reduces endothelial dysfunction in a glucose dependent manner.

Topics: Aged; Blood Glucose; Carbamates; Cross-Over Studies; Endothelium, Vascular; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Male; Middle Aged; Piperidines; Prospective Studies; Vascular Diseases

This study was conducted to compare the treatment efficacy between a prandial glucose regulator, repaglinide and a new sulphonylurea, glimepiride in Muslim Type 2 diabetic patients who practice Ramadan fasting. Forty-one patients, previously treated with a sulphonylurea or metformin, were divided to receive either repaglinide (n=20, preprandially three-times daily) or glimepiride (n=21, preprandially once daily) 3 months before the month of Ramadan. During Ramadan, patients modified their eating pattern to two meals daily, and the triple doses of repaglinide were redistributed to two preprandial doses. Four point blood glucose monitoring were performed weekly during the month of Ramadan and the subsequent month. Measurements of the 4-point blood glucose were significantly lower in the glimepiride group compared to the repaglinide group both during and after Ramadan. The glycaemic excursion was better in the morning for the repaglinide group and better in the afternoon and evening for the glimepiride group during the Ramadan period. There was no statistically significant difference in the incidence of hypoglycaemia between the two groups during and after Ramadan. There was no difference in the glycaemic excursion post-Ramadan. The longer duration of action of glimepiride may offer an advantage over repaglinide during the 13.5 hours of fast in Ramadan for diabetic patients.

Topics: Adult; Aged; Blood Glucose; Carbamates; Ceremonial Behavior; Diabetes Mellitus, Type 2; Fasting; Female; Humans; Hypoglycemic Agents; Islam; Male; Middle Aged; Piperidines; Sulfonylurea Compounds; Time Factors; Treatment Outcome

Topics: Aged; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Glyburide; Humans; Piperidines

In this study, we investigated the effects of combining preprandial repaglinide to the insulin therapy for reducing the exogenous insulin requirements and serum HbA(1c) levels in type 2 diabetic patients whose blood glucose levels were previously regulated by multiple dose intensive insulin therapy. Fifty patients with type 2 diabetes who had been initially treated with oral antidiabetic agents without a satisfactory response were included in this study. After adequate glycemic control was achieved with intensive insulin therapy, the patients were divided into two subgroups. The first group continued with intensive insulin therapy. The second group received a combination of multiple insulin injections and oral repaglinide (1.5 mgr tid). The doses of insulin injections were gradually decreased accordingly in the second group. Both groups were followed-up for 3 months. Repaglinide was well tolerated and had no toxicity. A significant reduction regarding exogenous insulin requirements and serum HbA(1c) levels were demonstrated in patients taking preprandial repaglinide (p<0.01). Combining repaglinide to intensive insulin therapy could be a safe and effective alternative to intensive insulin therapy alone for the glycemic control and for reducing exogenous insulin requirements in type 2 diabetic patients.

Topics: Body Mass Index; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Piperidines

The effect of repaglinide and gliclazide on postmeal suppression of endogenous glucose production (EGP) has been studied using a variable-rate tracer methodology. Groups of age-, sex-, and weight-matched type 2 diabetic subjects randomized to gliclazide or repaglinide were studied after ingesting a standard mixed meal (550 kcal; 67% carbohydrate, 19% fat, 14% protein). Plasma glucose profiles were similar in each group and markedly different from that of a nondiabetic control group. Endogenous glucose production was similar basally (3.01 +/- 0.30 vs 3.06 +/- 0.19 mg/kg per minute, gliclazide and repaglinide, respectively). After glucose ingestion, EGP declined rapidly in both the groups until 30 minutes and the greatest suppression was reached earlier in the repaglinide group [0.88 mg/kg per minute at 120 minutes vs 0.77 mg/kg per minute at 210 minutes in gliclazide group (P < .05); median time, 85 vs 195 minutes, respectively (P < .05)]. The area under the curve (30-150) for EGP was significantly greater in the gliclazide group than in the nondiabetic control group (109 +/- 11 vs 198 +/- 22 mg/kg per min 2 ; P > .02) but not significantly different in the repaglinide group (153 +/- 25 mg/kg per min 2 ; P = .17). Repaglinide has minimal physiological advantage over gliclazide, but both therapies for type 2 diabetes fall far short of correcting the endocrine and metabolic abnormalities.

Topics: Adult; Carbamates; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Gliclazide; Glucagon; Glucose; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Oxidation-Reduction; Piperidines; Postprandial Period

Several studies have demonstrated that endothelial dysfunction plays a central role in diabetic mortality and that the prooxidative effect of postprandial hyperglycemia may actively contribute to atherogenesis. Thus, we investigated the possible effect of short-acting (repaglinide) and long-acting (glibenclamide) insulin secretagogues on endothelial function in type 2 diabetic patients.. Sixteen type 2 diabetic patients undergoing diet treatment and with poor glucose control volunteered for the study. The study was designed as a 4-month, randomized, cross-over, parallel-group trial of repaglinide (1 mg twice a day) versus glibenclamide (5 mg twice a day). All patients underwent the following investigations: 1) anthropometrics determinations, 2) blood sampling for routine laboratory analyses and for assessment of oxidative stress indexes, and 3) a brachial reactivity test to evaluate the endothelial function through the study of arterial diameter and flow changes with and without intraarterial infusion of N(G)-monomethyl-l-arginine, an inhibitor of nitric oxide synthase and tetraethylammonium chloride (TEA), a Ca(2+)-activated K(+) (K(Ca)) channel blocker. All patients were randomly assigned to receive repaglinide or glibenclamide for a period of 4 weeks.. Repaglinide administration was associated with a significant reduction in 2-h plasma glucose levels (P < 0.001) and in plasma thiobarbituric acid-reactive substances (TBARS) concentrations (P < 0.001) and with a significant increase in plasma antioxidant power, assessed as Trolox equivalent antioxidant capacity (TEAC) (P < 0.001), effects not observed after glibenclamide administration. With regard to brachial reactivity parameters, repaglinide but not glibenclamide was associated with a significant improvement in brachial reactivity parameters (P < 0.003 for all parameters). In contrast, intra-arterial infusion of L-NMMA and TEA reduced the beneficial effect of repaglinide.. Repaglinide administration, through good control of postprandial glucose levels, improves brachial reactivity and declines oxidative stress indexes.

Topics: Aged; Blood Glucose; Brachial Artery; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Endothelium, Vascular; Female; Glyburide; Humans; Hypoglycemic Agents; Male; Middle Aged; Oxidative Stress; Piperidines

Repaglinide, a new insulin secretagogue, is purported to be as effective as sulphonylurea but is less hypoglycemic-prone.. To assess the efficacy of repaglinide and its proclivity for hypoglycemia in a post-marketing study.. The study group comprised 688 patients, aged 26-95 years, clinically diagnosed with non-insulin-dependent type 2 diabetes. The patients were divided into three groups based on previous therapy: a) sulphonylurea-treated (group 1, n = 132); b) metformin with or without sulphonylurea where sulphonylurea was replaced with repaglinide (group 2, n = 302); and c) lifestyle modification alone (drug-naive) (group 3, n = 254). At initiation of the study, all patients were transferred from their current treatment to repaglinide. Only patients in group 2, with combined sulphonylurea plus metformin, continued with metformin plus repaglinide. Fasting blood sugar, hemoglobin A1c and weight were measured at study entry and 4-8 weeks following repaglinide therapy. A questionnaire documented the number of meals daily and the presence of eating from fear of hypoglycemia.. The fasting blood sugar level of the entire cohort dropped from 191 +/- 2.4 to 155 +/- 2.0 mg/dl (P < 0.0001); HbA1c from 8.8 +/- 0.1 to 7.7 +/- 0.1% (P < 0.0001). The drop of HbA1c in groups 1, 2 and 3 respectively were: 1.04 +/- 0.22% (P < 0.0001), 1.14 +/- 0.24% (P < 0.0001), and 1.51 +/- 0.31% (P = 0.0137). Weight dropped from 81 +/- 0.7 to 80.2 +/- 0.7 kg (P < 0.0001), and eating from fear of hypoglycemia from 157 to 97 (P < 0.001). The daily number of meals decreased from 2.9 +/- 0.4 to 2.4 +/- 0.4 (P < 0.001). No serious adverse reactions occurred during the study.. Repaglinide is an effective oral hypoglycemic agent taken either as monotherapy or combination therapy. There is less eating to avoid hypoglycemia, fewer meals consumed, and weight loss.

Topics: Adult; Aged; Aged, 80 and over; Blood Glucose; Body Weight; Carbamates; Diabetes Mellitus, Type 2; Diet; Feeding Behavior; Female; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Stereoisomerism; Treatment Outcome

To compare the efficacy of nateglinide with repaglinide in the treatment of type 2 diabetes mellitus.. Forty-six type 2 diabetic patients were randomly treated with repaglinide (group A, 1.0 mg tid, n=23) or nateglinide (group B, 90.0 mg tid, n=23). The trial consisted of a 4-week equilibrated period followed by 12 weeks of treatment course.. In group A, the fasting blood glucose (FBG) and 30-, 60-, 120- min postprandial blood glucose (PBG), as well as hemoglobin A1c were decreased significantly (P<0.05). In group B, the 60-min and 120-min PBG decreased remarkably (P<0.05), but FBG, 30-min PBG and A1c decreased with no statistical significance (P>0.05). After 12 weeks treatment, the 30-, 60-, 120-min postprandial insulin level, area under the curve of insulin and C peptide (0 to 120 min) increased in both groups (P<0.05). No significant difference was found between the effects of repaglinide and nateglinide on early phase insulin secretion.. The glucose lowering effect of repaglinide at a dosing level of 1.0 mg tid was better than that of nateglinide 90 mg tid on fasting blood glucose and A1c during 12 weeks treatment period, yet the insulinotropic effects of the two drugs were similar.

Topics: Adult; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines

To assess the effects of incremental doses of repaglinide on postprandial insulin and glucose profiles after a standard 500-kcal test meal.. Sixteen diet-treated Caucasians with type 2 diabetes (mean HbA(1c) 8.4%) were enrolled in this randomized, open-label, crossover trial. Subjects received 0.5, 1, 2, and 4 mg repaglinide or placebo in a random fashion, followed by a standard 500-kcal test meal on 5 separate study days, 1 week apart.. The insulinogenic index (DeltaI30/DeltaG30) and insulin area under the curve (AUC) from 0 to 30 min (AUC(0-30)) were higher with the 4-mg drug dose compared with the two lower doses and with 2 mg compared with 0.5 mg. On subgroup analysis, the incremental insulin responses were apparent only in the fasting plasma glucose (FPG) < 9-mmol/l subgroup of subjects and not in the FPG >9-mmol/l subgroup. There was a significant dose-related increase in the late postprandial insulin secretion (insulin AUC(120-240)), which resulted in hypoglycemia in four subjects. Proinsulin-to-insulin ratios at 30 and 60 min improved with increasing doses of repaglinide; higher drug doses (2 and 4 mg) were more effective than the 0.5- and 1-mg doses.. Significant dose-related increases in early insulin secretion were found only in less advanced diabetic subjects. In advanced diabetic patients, only the maximum dose (4 mg) was significant compared with placebo. Better proinsulin-to-insulin processing was noted with increasing drug doses.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Eating; Female; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Male; Middle Aged; Piperidines; Postprandial Period

Topics: Adult; Blood Glucose; Body Mass Index; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin, Isophane; Male; Patient Dropouts; Piperidines

Aim our study is to compare the effects of repaglinide vs glimepiride administration on cardiovascular risk factors after meal test. Thus, after 2 weeks washout period, a 3-month randomised, cross-over parallel group trial of repaglinide (1 mg x 2/day) vs glimepiride (2 mg/day) in 14 patients with type 2 diabetes "naive" on diet treatment was made. Both treatments significantly declined plasma glucose, total-cholesterol, LDL-cholesterol, triglycerides, PAI-1, PAP levels and increased HDL-cholesterol. Lowering in plasma PAI-1 and PAP levels was significantly greater in repaglinide group. Furthermore, repaglinide administration resulted in a significant decrease in fasting plasma free fatty acids, fibrinogen, thrombin-antithrombin complex and reaction product of malondialdehyde with thiobarbituric acid (TBARS) levels, in absence of significant difference in fasting plasma insulin levels. Decrease in plasma TBARS levels correlated with the decrease in Plasminogen Activator Inhibitor-1 (r = 0.72; P < 0.003) and free fatty acids concentrations (r = 0.62; P < 0.01). Analysis of the insulin and glucose concentrations throughout the meal test revealed that AUC for glucose (758 +/- 19 vs 780 +/- 28 mg/Lxmin; P = 0.02) was significantly lower after repaglinide than glimepiride administration despite similar AUC for insulin (2327 +/- 269 vs 2148 +/- 292 mU/Lxmin; P = 0.105). At time 120' of meal test, repaglinide vs glimepiride administration was associated with a significant decline in plasma triglycerides, free fatty acids, fibrinogen, Plasminogen Activator Inhibitor-1, plasmin-alpha(2)-antiplasmin complex, thrombin-antithrombin complex, TBARS levels and increase in plasma HDL-cholesterol levels. In repaglinide group a negative correlation between insulin secretion during 1st phase of meal-test and plasma TBARS levels (r = -0.55; P < 0.03) at time 120' was found. Such correlation was lost after adjusting for changes in postprandial hyperglycaemia (r = -0.48; P < 0.09). In conclusion, our results support the hypothesis that repaglinide is more efficient than glimepiride on controlling for postprandial glucose excursion and may have beneficial effect on reducing cardiovascular risk factors.

Topics: Aged; Aged, 80 and over; Area Under Curve; Blood Glucose; Carbamates; Cardiovascular Diseases; Cross-Over Studies; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diet, Diabetic; Eating; Female; Humans; Hypoglycemic Agents; Insulin; Lipids; Male; Middle Aged; Piperidines; Sulfonylurea Compounds; Thiobarbituric Acid Reactive Substances

First-phase insulin release and coordinated insulin pulsatility are disturbed in Type 2 diabetes. The present study was undertaken to explore a possible influence of the oral prandial glucose regulator, repaglinide, on first-phase insulin secretion and high-frequency insulin pulsatility in Type 2 diabetes.. We examined 10 patients with Type 2 diabetes in a double-blind placebo-controlled, cross-over design. The participants were treated for 6 weeks with either repaglinide [2-9 mg/day (average 5.9 mg)] or placebo in random order. At the end of each treatment period, first-phase insulin secretion was measured. Entrainment of insulin secretion was assessed utilizing 1-min glucose bolus exposure (6 mg/kg body weight every 10 min) for 60 min during (A) baseline conditions, i.e. 12 h after the last repaglinide/placebo administration, and (B) 30 min after an oral dose of 0.5 mg repaglinide/placebo with subsequent application of time-series analyses.. Postprandial (2-h) blood glucose was significantly reduced by repaglinide after 5 weeks of treatment (P < 0.001). The fall in HbA(1c) did not reach statistical significance (P = 0.07). AUC(ins,0-12 min) during the first-phase insulin secretion test was enhanced (P < 0.05). In addition, glucose entrained insulin secretory burst mass and amplitude increased markedly (burst mass: repaglinide, 44.4 +/- 6.0 pmol/l/pulse vs. placebo, 31.4 +/- 3.3 pmol/l/pulse, P < 0.05; burst amplitude: repaglinide, 17.7 +/- 2.4 pmol/l/min vs. placebo, 12.6 +/- 1.3 pmol/l/min, P < 0.05) while basal insulin (non-pulsatile) secretion was unaltered. After acute repaglinide exposure (0.5 mg) basal insulin secretion increased significantly (P < 0.05). Neither acute nor chronic repaglinide administration influenced frequency or regularity of insulin pulses during entrainment.. Repaglinide augments first-phase insulin secretion as well as high-frequency insulin secretory burst mass and amplitude during glucose entrainment in patients with Type 2 diabetes, while regularity of the insulin release process was unaltered.

Topics: Administration, Oral; Adult; Aged; Blood Glucose; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Homeostasis; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Middle Aged; Piperidines; Secretory Rate

Repaglinide is an antidiabetic drug metabolized by cytochrome P450 (CYP) 2 C 8 and 3A4, and it appears to be a substrate of the hepatic uptake transporter organic anion transporting polypeptide 1B1 (OATP1B1). We studied the effects of cyclosporine (INN, ciclosporin), an inhibitor of CYP3A4 and OATP1B1, on the pharmacokinetics and pharmacodynamics of repaglinide.. In a randomized crossover study, 12 healthy volunteers took 100 mg cyclosporine or placebo orally at 8 pm on day 1 and at 8 am on day 2. At 9 am on day 2, they ingested a single 0.25-mg dose of repaglinide. Concentrations of plasma and urine repaglinide and its metabolites (M), blood cyclosporine, and blood glucose were measured for 12 hours. The subjects were genotyped for single-nucleotide polymorphisms in CYP2C8, CYP3A5, SLCO1B1 (encoding OATP1B1), and ABCB1 (P-glycoprotein). The effect of cyclosporine on repaglinide metabolism was studied in human liver microsomes in vitro.. During the cyclosporine phase, the mean peak repaglinide plasma concentration was 175% (range, 56%--365%; P=.013) and the total area under the plasma concentration-time curve [AUC0--infinity] was 244% (range, 119%--533%; P<.001) of that in the placebo phase. The amount of unchanged repaglinide and its metabolites M2 and M4 excreted in urine were raised 2.7--fold, 7.5--fold, and 5.0--fold, respectively, by cyclosporine (P<.001). The amount of M1 excreted in urine remained unchanged, but cyclosporine reduced the ratio of M1 to repaglinide by 62% (P<.001). Cyclosporine had no significant effect on the elimination half-life or renal clearance of repaglinide. Although the mean blood glucose-lowering effect of repaglinide was unaffected in this low-dose study with frequent carbohydrate intake, the subject with the greatest pharmacokinetic interaction had the greatest increase in blood glucose-lowering effect. The effect of cyclosporine on repaglinide AUC0-infinity was 42% lower in subjects with the SLCO1B1 521TC genotype than in subjects with the 521TT (reference) genotype (P=.047). In vitro, cyclosporine inhibited the formation of M1 (IC50 [concentration of inhibitor to cause 50% inhibition of original enzyme activity], 0.2 micromol/L) and M2 (IC50, 4.3 micromol/L) but had no effect on M4.. Cyclosporine raised the plasma concentrations of repaglinide, probably by inhibiting its CYP3A4-catalyzed biotransformation and OATP1B1-mediated hepatic uptake. Coadministration of cyclosporine may enhance the blood glucose-lowering effect of repaglinide and increase the risk of hypoglycemia.

Topics: Adult; Aryl Hydrocarbon Hydroxylases; ATP Binding Cassette Transporter, Subfamily B, Member 1; Blood Glucose; Carbamates; Cross-Over Studies; Cyclosporine; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Drug Synergism; Genotype; Humans; Hypoglycemic Agents; Immunosuppressive Agents; In Vitro Techniques; Liver-Specific Organic Anion Transporter 1; Male; Microsomes, Liver; Organic Anion Transporters; Piperidines; Polymorphism, Single Nucleotide

In vitro data have recently suggested that sulfonylureas (SUs) enhance GH secretion by modulating the effects of GHRH and somatostatin in pituitary cells. The present study was undertaken to explore in more detail a possible influence of a single dose of SU (glibenclamide) and a non-SU (repaglinide) insulin secretagogue on circulating GH dynamics. Ten C-peptide-negative type 1 diabetic individuals were examined on three occasions in random order. Either glibenclamide (10.5 mg), repaglinide (8 mg), or placebo was administered after overnight normalization of plasma glucose by iv insulin infusion. Subsequently, GH concentrations were measured regularly after stimulation with GHRH (bolus 0.1 micro g/kg) alone and during concomitant infusion with somatostatin (7 ng.kg(-1).min(-1)). Insulin was replaced at baseline levels (0.25 mU.kg(-1).min(-1)) and plasma glucose clamped at 5-6 mmol/liter. Overall, there were no significant statistical differences in GH responses determined as either GH peak concentrations, integrated levels of GH, or secretory burst mass of GH during the experimental protocol. In contrast, plasma glucagon concentrations were significantly increased during glibenclamide and repaglinide exposure. The present experimental design does not support the hypothesis that acute administration of pharmacological doses of the oral antihyperglycemic agents glibenclamide and repaglinide per se enhance GH release in humans. Additionally, this study shows that these potassium channel inhibitors seem to stimulate glucagon secretion in people who have severe intraislet insulin deficiency (e.g. type 1 diabetes). However, extrapolation of our findings to type 2 diabetic individuals should be done with some caution.

Topics: Blood Glucose; C-Peptide; Carbamates; Diabetes Mellitus, Type 1; Fatty Acids, Nonesterified; Glucagon; Glucose Clamp Technique; Glyburide; Growth Hormone-Releasing Hormone; Human Growth Hormone; Humans; Hypoglycemic Agents; Insulin; Piperidines; Placebos; Potassium Channel Blockers; Somatostatin

The efficacy and safety of combination therapy (repaglinide plus pioglitazone) was compared to repaglinide or pioglitazone in 24-week treatment of type 2 diabetes. This randomized, multicenter, open-label, parallel-group study enrolled 246 adults (age 24-85) who had shown inadequate response in previous sulfonylurea or metformin monotherapy (HbA(1c) > 7%). Prior therapy was withdrawn for 2 weeks, followed by randomization to repaglinide, pioglitazone, or repaglinide/pioglitazone. In the first 12 weeks of treatment, repaglinide doses were optimized, followed by 12 weeks of maintenance therapy. Pioglitazone dosage was fixed at 30 mg per day. Baseline HbA(1c) values were comparable (9.0% for repaglinide, 9.1% for pioglitazone, 9.3% for combination). Mean changes in HbA(1c) values at the end of treatment were -1.76% for repaglinide/pioglitazone, -0.18% for repaglinide, +0.32% for pioglitazone. Fasting plasma glucose reductions were -82 mg/dl for combination therapy, -34 mg/dl for repaglinide, -18 mg/dl for pioglitazone. Minor hypoglycemia occurred in 5% of patients for the combination, 8% for repaglinide, and 3% for pioglitazone. Weight gains for combination therapy were correlated to individual HbA(1c) reductions. In summary, for patients who had previously failed oral antidiabetic monotherapy, the combination repaglinide/pioglitazone had acceptable safety, with greater reductions of glycemic parameters than therapy using either agent alone.

Topics: Adult; Aged; Aged, 80 and over; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Lipids; Middle Aged; Pioglitazone; Piperidines; Thiazolidinediones

Our aim was to investigate the effect of the CYP2C8 inhibitor trimethoprim on the pharmacokinetics and pharmacodynamics of the antidiabetic drug repaglinide, and to examine the influence of the former on the metabolism of the latter in vitro.. In a randomized, double-blind, crossover study with two phases, nine healthy volunteers took 160 mg trimethoprim or placebo orally twice daily for 3 days. On day 3, 1 h after the last dose of trimethoprim or placebo, they ingested a single 0.25 mg dose of repaglinide. Plasma repaglinide and blood glucose concentrations were measured for up to 7 h post-dose. In addition, the effect of trimethoprim on the metabolism of repaglinide by human liver microsomes was investigated.. Trimethoprim raised the AUC(0, infinity ) and C(max) of repaglinide by 61% (range, 30-117%; P= 0.0008) and 41% (P = 0.005), respectively, and prolonged the t((1/2)) of repaglinide from 0.9 to 1.1 h (P = 0.001). Trimethoprim had no significant effect on the pharmacokinetics of its aromatic amine metabolite (M1), but decreased the M1 : repaglinide AUC(0, infinity ) ratio by 38% (P = 0.0005). No effect of trimethoprim on the blood glucose-lowering effect of repaglinide was detectable. In vitro, trimethoprim inhibited the metabolism of (220 nm) repaglinide in a concentration-dependent manner.. Trimethoprim raised the plasma concentrations of repaglinide probably by inhibiting its CYP2C8-mediated biotransformation. Although the interaction did not significantly enhance the effect of repaglinide on blood glucose concentration at the drug doses used, the possibility of an increased risk of hypoglycaemia should be considered during concomitant use of trimethoprim and repaglinide in patients with diabetes.

Topics: Adult; Aryl Hydrocarbon Hydroxylases; Biotransformation; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP2C8; Diabetes Mellitus; Double-Blind Method; Drug Interactions; Female; Humans; Hypoglycemic Agents; Male; Piperidines; Trimethoprim

To compare the effect of Repaglinide vs Glimepiride on glucose- and meal-induced insulin secretion and on meal-test induced postprandial glucose excursions.. After 2 weeks washout period, a 3-Month randomised, cross-over parallel group trial of R (1 mg x 2/die) vs G (2 mg/die) in 14 patients with type 2 diabetes "naive" in diet treatment was made.. Both R and G significantly but similarly lowered fasting glucose levels and improved fasting plasma insulin levels vs baseline. Hyperglycemic clamp showed that both 1st (129.15 +/- 23.6 vs 106.90 +/- 18.6 pmol/L; p=0.01) and 2nd phase (189.42 +/- 34.4 vs 144.21 +/- 37.3 pmol/L; p=0.003) B-cell response to glucose as well as area under the curve (52.07 +/- 10.86 vs 39.54 +/- 10.27 micromol/L x 120'; p=0.005) were greater in R than G groups. Insulin action (4.0 +/- 1.1 vs 3.2 +/- 0.9 mg x Kg x 60'/microU/mL; p=0.046) was also improved by R than G administration. In the meal test, R therapy produced a more rapId induction of insulin secretion during the first part. In fact, the mean rise in insulin secretion peaked at 45 min in R (p=0.001 vs G) and at 60 min in G (p=0.001 vs R). Consequently, glucose spike at 60 min was higher in G group compared to glucose spike at 45 min in R group (p=0.002).. Our study demonstrates that R is more efficient that G on improving glucose- and meal- induced insulin secretion as well as on controlling for postprandial glucose excursion.

Topics: Aged; Aged, 80 and over; Blood Glucose; C-Peptide; Carbamates; Cholesterol; Diabetes Mellitus, Type 2; Female; Glucose Clamp Technique; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Kinetics; Male; Middle Aged; Piperidines; Postprandial Period; Sulfonylurea Compounds; Time Factors; Triglycerides

To investigate if rifampicin is both an inducer and an inhibitor of repaglinide metabolism, it was determined whether the timing of rifampicin co-administration influences the pharmacokinetics of repaglinide.. Male volunteers ( n=12) participated in a randomised, two-period, crossover trial evaluating the effect of multiple doses of 600 mg rifampicin once daily for 7 days on repaglinide metabolism. Subjects were, after baseline measurements of repaglinide pharmacokinetics, randomised to receive, on either day 7 or day 8 of the rifampicin administration period, a single dose of 4 mg repaglinide and vice versa in the following period.. When repaglinide was given, together with the last rifampicin dose, on day 7, an almost 50% reduction of the median repaglinide area under the plasma concentration-time curve (AUC) was observed. Neither the peak plasma concentration (C(max)), time to reach C(max) (t(max)) nor terminal half-life (t(1/2)) was statistically significantly affected. When repaglinide was given on day 8, 24 h after the last rifampicin dose, an almost 80% reduction of the median repaglinide AUC was observed. The median C(max) was now statistically significantly reduced from 35 ng/ml to 7.5 ng/ml. Neither t(max) nor t(1/2) was significantly affected.. When rifampicin and repaglinide are administered concomitantly, rifampicin seems to act as both an inducer and an inhibitor of the metabolism of repaglinide. After discontinuing rifampicin administration, while the inductive effect on CYP3A4 and probably also CYP2C8 is still present, an even more marked reduction in the plasma concentration of repaglinide was observed. Our results suggest that concomitant administration of rifampicin and repaglinide may cause a clinically relevant decrease in the glucose-lowering effect of repaglinide, in particular when rifampicin treatment is discontinued or if the drugs are not administered simultaneously or within a few hours of each other.

Topics: Administration, Oral; Adolescent; Adult; Anti-Bacterial Agents; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Carbamates; Chromatography, High Pressure Liquid; Cross-Over Studies; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drug Interactions; Enzyme Induction; Humans; Hydrocortisone; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Quinidine; Rifampin; Time Factors

A total of 385 drug-therapy naïve patients, with inadequately controlled type 2 diabetes, were randomised into a multinational, parallel-group study to compare two strategies for dose titration of the oral hypoglycaemic agent repaglinide. Patients were allocated to either a fasting blood glucose (FBG) monitoring group with titration target 4.4-6.1 mmol/l or to a post-prandial blood glucose (PPBG) monitoring group with titration target 4.4-8.0 mmol/l. An initial titration period of up to 8 weeks was followed by a 12-week treatment period. Glycaemic control and hypoglycaemic outcomes were compared for the respective groups. HbA(1c) decreased significantly more in the FBG monitoring group by a mean of 1.38% compared to the PPBG group by a mean of 1.22% (P=0.03). The glycaemic control targets were met by fewer patients in the FBG group than in the PPBG group (57% versus 86% (P<0.001)) despite a higher mean dose of repaglinide in the FBG group. The within-patient blood glucose variability was significantly lower in the FBG group than in the PPBG group (P<0.001). In conclusion, repaglinide lowered the HbA(1c) effectively and safely in both groups and self-monitored FBG is a suitable parameter for titration of repaglinide. Whether a lower PPBG target might be as good a guide as FBG for titration of repaglinide should be addressed in a future study.

Topics: Adult; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Fasting; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Piperidines; Postprandial Period; Safety

This 24-week, randomized, multicentre, open-label, parallel-group clinical trial compared efficacy and safety of repaglinide monotherapy, rosiglitazone monotherapy, and combination therapy (repaglinide plus rosiglitazone) in Type 2 diabetes after unsatisfactory response to sulphonylurea or metformin monotherapy.. Enrolled patients (n = 252) were adults having Type 2 diabetes for at least 1 year, with HbA(1c) values > 7.0% after previous monotherapy (sulphonylurea or metformin, >/= 50% maximal dose). Prior therapy was withdrawn for 2 weeks, followed by randomization to repaglinide, rosiglitazone, or repaglinide/rosiglitazone. Study treatments were initiated with a 12-week dose optimization period (doses optimized according to labelling), followed by a 12-week maintenance period. Efficacy endpoints were changes in HbA(1c) values (primary) or fasting plasma glucose values (secondary).. Baseline HbA(1c) values were comparable (9.3% for repaglinide, 9.0% for rosiglitazone, 9.1% for combination). Mean changes in HbA(1c) values at the end of treatment were greater for repaglinide/rosiglitazone therapy (-1.43%) than for repaglinide (-0.17%) or rosiglitazone (-0.56%) monotherapy. Reductions of fasting plasma glucose values were also greater for combination therapy (-5.2 mmol/l, -94 mg/dl) than for repaglinide monotherapy (-3.0 mmol/l, -54 mg/dl) or rosiglitazone monotherapy (-3.7 mmol/l, -67 mg/dl). Minor hypoglycaemic events occurred in 9% of combination therapy patients, vs. 6% for repaglinide and 2% for rosiglitazone. Individual weight gains for combination therapy were correlated to HbA(1c) response.. The combination therapy regimen was well tolerated. In patients previously showing unsatisfactory response to oral monotherapy, glycaemic reductions were greater for the repaglinide/rosiglitazone combination regimen than for use of either repaglinide or rosiglitazone alone.

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Rosiglitazone; Thiazolidinediones; Treatment Outcome; Weight Gain

A randomized, parallel-group, open-label, multicenter 16-week clinical trial compared efficacy and safety of repaglinide monotherapy and nateglinide monotherapy in type 2 diabetic patients previously treated with diet and exercise.. Enrolled patients (n = 150) had received treatment with diet and exercise in the previous 3 months with HbA(1c) >7 and < or =12%. Patients were randomized to receive monotherapy with repaglinide (n = 76) (0.5 mg/meal, maximum dose 4 mg/meal) or nateglinide (n = 74) (60 mg/meal, maximum dose 120 mg/meal) for 16 weeks. Primary and secondary efficacy end points were changes in HbA(1c) and fasting plasma glucose (FPG) values from baseline, respectively. Postprandial glucose, insulin, and glucagon were assessed after a liquid test meal (baseline, week 16). Safety was assessed by incidence of adverse events or hypoglycemia.. Mean baseline HbA(1c) values were similar in both groups (8.9%). Final HbA(1c) values were lower for repaglinide monotherapy than nateglinide monotherapy (7.3 vs. 7.9%). Mean final reductions of HbA(1c) were significantly greater for repaglinide monotherapy than nateglinide monotherapy (-1.57 vs. -1.04%; P = 0.002). Mean changes in FPG also demonstrated significantly greater efficacy for repaglinide than nateglinide (-57 vs. -18 mg/dl; P < 0.001). HbA(1c) values <7% were achieved by 54% of repaglinide-treated patients versus 42% for nateglinide. Median final doses were 6.0 mg/day for repaglinide and 360 mg/day for nateglinide. There were 7% of subjects treated with repaglinide (five subjects with one episode each) who had minor hypoglycemic episodes (blood glucose <50 mg/dl) versus 0 patients for nateglinide. Mean weight gain at the end of the study was 1.8 kg in the repaglinide group as compared with 0.7 kg for the nateglinide group.. In patients previously treated with diet and exercise, repaglinide and nateglinide had similar postprandial glycemic effects, but repaglinide monotherapy was significantly more effective than nateglinide monotherapy in reducing HbA(1c) and FPG values after 16 weeks of therapy.

Topics: Biomarkers; Body Mass Index; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Diet, Diabetic; Exercise; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines; Time Factors

Postprandial hyperglycemia may be a risk factor for cardiovascular disease. We compared the effects of two insulin secretagogues, repaglinide and glyburide, known to have different efficacy on postprandial hyperglycemia, on carotid intima-media thickness (CIMT) and markers of systemic vascular inflammation in type 2 diabetic patients.. We performed a randomized, single-blind trial on 175 drug-naive patients with type 2 diabetes mellitus (93 men and 82 women), 35 to 70 years of age, selected from a population of 401 patients who participated in an epidemiological analysis assessing the relation of postprandial hyperglycemia to surrogate measures of atherosclerosis. Eighty-eight patients were randomly assigned to receive repaglinide and 87 patients to glyburide, with a titration period of 6 to 8 weeks for optimization of drug dosage and a subsequent 12-month treatment period. The effects of repaglinide (1.5 to 12 mg/d) and glyburide (5 to 20 mg/d) on CIMT were compared by using blinded, serial assessments of the far wall. After 12 months, postprandial glucose peak was 148+/-28 mg/dL in the repaglinide group and 180+/-32 mg/dL in the glyburide group (P<0.01). HbA(1c) showed a similar decrease in both groups (-0.9%). CIMT regression, defined as a decrease of >0.020 mm, was observed in 52% of diabetics receiving repaglinide and in 18% of those receiving glyburide (P<0.01). Interleukin-6 (P=0.04) and C-reactive protein (P=0.02) decreased more in the repaglinide group than in the glyburide group. The reduction in CIMT was associated with changes in postprandial but not fasting hyperglycemia.. Reduction of postprandial hyperglycemia in type 2 diabetic patients is associated with CIMT regression.

Topics: Adult; Aged; Biomarkers; Blood Glucose; Carbamates; Carotid Artery Diseases; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Fasting; Female; Glyburide; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemic Agents; Inflammation; Insulin; Lipids; Male; Middle Aged; Piperidines; Postprandial Period; Single-Blind Method; Tunica Intima; Tunica Media; Ultrasonography

The effects of a combination of repaglinide and metformin on the insulin secretion pattern and insulin sensitivity were studied in a fixed-dose, open-label, placebo-controlled cross-over study. Eleven patients with T2 DM were allocated in random order to treatment with placebo or repaglinide (1 mg pre-meal 3 x/day) in combination with metformin (2550 mg/day) for one-week periods of each. At the end of each period a hyperglycaemic (HC) and a euglycaemic clamp (EC) were performed. Both early (0 - 10 min) and late (25 - 180 min) phases of insulin secretion were significantly increased during HC with repaglinide compared to placebo (263.3 +/- 133.1 vs. 443.6 +/- 138.5 pmol/l/10 min, p = 0.008 and 18 750.9 +/- 5936.4 vs. 34 508.65 +/- 9234.0 pmol/l/25 - 180 min; p = 0.008). The C-peptide concentrations under steady-state conditions were lower in EC with placebo than with repaglinide (p = 0.014). When euglycaemia was achieved in EC, the C-peptide concentrations decreased from hyperglycaemic to normoglycaemic values in the presence of repaglinide but remained higher than after placebo. The insulin sensitivity index (ISI) was increased by 35 % after 1 week of combination therapy with repaglinide plus metformin (1.11 +/- 0.03 x 10 (2) vs. 0.83 +/- 0.21 x 10 (2) mg x kg (-1) body weight x min (-1) x pmol (-1) x l, respectively; p = 0.033). Repaglinide increased early and late phases of insulin responses in HC, without markedly enhancing insulin secretion in euglycaemia. Repaglinide in combination with metformin produced a significant enhancement of ISI, suggesting a synergistic effect on insulin sensitivity.

Topics: Adult; Aged; C-Peptide; Carbamates; Cohort Studies; Cross-Over Studies; Diabetes Mellitus, Type 2; Drug Synergism; Drug Therapy, Combination; Female; Glucose Clamp Technique; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Metformin; Middle Aged; Piperidines; Placebos; Time Factors

This study was designed to compare the effects of repaglinide plus acarbose combination treatment to repaglinide alone on postprandial glucose, serum insulin, C-peptide and proinsulin concentrations. A total of 40 patients with Type 2 diabetes (T2DM) (fasting blood glucose: 120-180 mg/dl; postprandial blood glucose: 140-240 mg/dl) were included in this single-centre, controlled, randomised, single-dose, cross-over study. On two consecutive days, patients either received 2 mg repaglinide 15 min before breakfast followed by 100 mg acarbose with breakfast or repaglinide alone. Two fasting (7.30 h, 8.00 h) and five postprandial blood samples (from 8.30 h to 12.00 h) were taken for blood glucose, serum insulin, C-peptide and proinsulin determination. Repaglinide plus acarbose treatment significantly reduced the mean increase in postprandial blood glucose levels (24.2+/-18.2 mg/dl) compared to repaglinide alone (51.1+/-29.0 mg/dl; p<0.001). Serum insulin, C-peptide and proinsulin levels [mean area under the curve (AUC7.30-12.00h)] were significantly lower than those observed with repaglinide monotherapy (e.g. insulin: 1089.2+/-604.5 hr x pmol/l and 1596.8+/-1080.6 hr x pmol/l, resp., p<0.001), suggesting that acarbose modifies the rapid insulin release induced by repaglinide. Prandial treatment with a combination of acarbose and repaglinide results in an additive glucose lowering effect and modified insulin secretion compared to repaglinide alone. Postprandial hyperglycaemia is not abolished by rapid stimulation of insulin release induced by repaglinide. Additional reduction of postprandial blood glucose by acarbose modifies the stimulation of insulin release.

Topics: Acarbose; Adult; Aged; Blood Glucose; C-Peptide; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Food; Humans; Hypoglycemic Agents; Insulin; Islets of Langerhans; Male; Middle Aged; Piperidines; Proinsulin

Oral hypoglycemic agents bind to the ATP-sensitive potassium channel and lower glucose levels effectively in individuals with diabetes. Although the principle mechanism of action can also promote hypoglycemia, clinically profound hypoglycemia is rare. Decreased stimulation of insulin secretion by these agents at mild hypoglycemia could provide protection from more profound hypoglycemia. Sulfonylureas and meglitinides bind to both shared and unique sites on the ATP-sensitive potassium receptor/channel complex but have different pharmacokinetic profiles. To evaluate the differential ability of both sulfonylureas and meglitinides to stimulate insulin release at modest hypoglycemia, we evaluated dextrose infusion rates necessary to maintain plasma glucose after oral administration of repaglinide (1 mg) or glipizide (5 mg) at euglycemia and again at modest hypoglycemia. Healthy subjects with no family history of diabetes underwent four clamp studies, two performed while maintaining isoglycemia (glucose levels at the fasted value) and two while maintaining modest hypoglycemia of 2.78 mmol/liter (50 mg/dl) induced by low-dose insulin infusion (3.6 pmol/kg.min). There was a marked decrease in the dextrose infusion rate with administration of either repaglinide or glipizide at hypoglycemia compared with drug administration at euglycemia (P

Topics: Administration, Oral; Adult; Carbamates; Cross-Over Studies; Double-Blind Method; Female; Glipizide; Glucose; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Male; Piperidines

Gemfibrozil markedly increases the plasma concentrations and blood glucose-lowering effects of repaglinide, but the effects of other fibrates on repaglinide pharmacokinetics are not known. Our aim was to investigate the effects of bezafibrate and fenofibrate on the pharmacokinetics and pharmacodynamics of repaglinide.. In a randomized, three-phase cross-over study, 12 healthy subjects received 400 mg bezafibrate, 200 mg fenofibrate or placebo once daily for 5 days. On day 5, a single 0.25 mg dose of repaglinide was ingested 1 h after the last pretreatment dose. The concentrations of plasma repaglinide, bezafibrate and fenofibrate and blood glucose were measured up to 7 h postdose.. During the bezafibrate and fenofibrate phases, the total area under the concentration-time curve [AUC(0, infinity )] of repaglinide was 99% (95% confidence interval of the ratio to the control phase 73, 143%) and 99% (85, 127%) of the corresponding value during the placebo (control) phase, respectively. Bezafibrate and fenofibrate had no significant effect on the peak concentration (Cmax) of repaglinide. The mean half-life of repaglinide was 1.3 h in all phases. The blood glucose-lowering effect of repaglinide was not affected by bezafibrate or fenofibrate. The AUC(0,8 h) values for bezafibrate and fenofibrate varied 3.0-fold and 4.4-fold between individual subjects, respectively. Neither bezafibrate nor fenofibrate affected the pharmacokinetic variables of repaglinide.. Bezafibrate and fenofibrate do not affect the pharmacokinetics or pharmacodynamics of repaglinide.

Topics: Adult; Bezafibrate; Blood Glucose; Carbamates; Cross-Over Studies; Delayed-Action Preparations; Drug Interactions; Fenofibrate; Humans; Hypolipidemic Agents; Male; Piperidines; Tablets

To examine the effect of short-term improvements in glycaemic control on brachial artery endothelial function as a marker of cardiovascular health.. Persons with Type 2 diabetes who were poorly controlled on oral therapy were randomly assigned to monotherapy with repaglinide or combination therapy with repaglinide plus metformin. Brachial artery flow-mediated vasodilation was assessed by ultrasonography at randomization and following 16 weeks of therapy. The primary outcome was change in brachial artery endothelial function from baseline. Comparison of randomized groups was a secondary aim.. Eighty-six participants were randomized, and 83 were followed to study completion. Post occlusion brachial artery vasodilation was 3.74% at baseline and 3.82% following 16 weeks of therapy (P = 0.77). The treatment effect was 0.08% (95% CI: -0.48%, 0.64%). No difference was seen between treatment groups (P = 0.69). Overall, A1C was reduced from 8.3% to 7.0%, with a greater reduction in the combination therapy group (from 8.4% to 6.7%) than in the monotherapy group (from 8.3% to 7.3%, p for difference between groups = 0.01). Statistically significant reductions were observed in fasting glucose, and plasminogen activator inhibitor-1. Statistically significant increases were observed for fasting insulin, uric acid, weight and BMI.. Brachial artery endothelial function was not influenced by short-term improvements in glycaemic control. The CONTROL DM group was successful in lowering A1C. Future research should explore more intensive and longer-lasting improvements in glycaemic control on endothelial function. Some data previously published in abstract form (Diabetes 2001; 50 (Suppl. 2): A217).

Topics: Administration, Oral; Adult; Aged; Brachial Artery; Carbamates; Combined Modality Therapy; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Treatment Outcome; Vasodilation

Diabetes and its treatment can cause problems for the Muslim population. The aim of this study was to evaluate the effect of different therapy models on clinical and metabolic status in type 2 diabetic patients during Ramadan.. Fifty-two type 2 diabetic patients were included to this study. Twelve of patients were on diabetic diet only before and during Ramadan (Group 1). Forty of patients had had sulfonylurea (Glimepiride 23 patients, gliclazide 17 patients) before Ramadan. Thirteen of these patients were on a single dose sulfonylurea (Glimepiride 8 patients, gliclazide 5 patients) (Group 2) and 27 were on Repaglinide 2 x 2 mg (Group 3) during Ramadan. Beta-hydroxybutyric acid, glucose, fructosamine, HbA1c, lipid levels and body weight were measured before and after Ramadan.. Body weight, fasting plasma glucose, fructosamine, HbA1c, total cholesterol were not changed in groups during the study. Triglyceride level decreased after Ramadan in groups 2 (p = 0.002) and 3 (p = 0.024). HDL-cholesterol level increased in group 3 (p = 0.022). Fasting capillary beta-hydroxybutyric acid level increased in group 1 (p = 0.034) and didn't change in groups 2 and 3 during the Ramadan. Only one hypoglycemic event occurred at day 6 of Ramadan in patients in group 2 (the patient was on 3 mg glimepiride).. Our results conclude that Ramadan fasting affects metabolic parameters in type 2 diabetes and hypoglycemia should be kept in mind especially in patients using sulfonylurea treatment. Ramadan fasting is not advised for type 2 diabetics while taking medical therapy. If the patient wants Ramadan fasting, these patients using Repaglinide can reduce the frequency of hypoglycemia.

Topics: 3-Hydroxybutyric Acid; Blood Glucose; Carbamates; Cholesterol, HDL; Diabetes Mellitus, Type 2; Fasting; Humans; Hypoglycemic Agents; Islam; Middle Aged; Piperidines; Postprandial Period; Sulfonylurea Compounds; Triglycerides

Repaglinide is an oral anti-diabetic agent that has a short duration of action, and is suitable for preventing post-prandial rises in glucose levels. Targeting post-prandial glucose levels may lead to lower HbA(1c) levels and rates of hypoglycaemia than targeting pre-prandial glucose levels.. In 42 centres, 193 drug-naive (n = 122) or metformin-treated (n = 71) individuals with Type 2 diabetes were randomly allocated to a 40-day period of repaglinide dose-titration (starting at 0.5 mg three times daily) based on either self-measured pre-prandial or post-prandial glucose levels. They were followed for a further 12 weeks and HbA(1c) and hypoglycaemia rates were recorded.. Repaglinide reduced HbA(1c) by 1.25 and 1.07% in the post-prandial and pre-prandial groups, respectively (P for difference = 0.6), and achieved target glucose levels in 80.7 and 66.7%, respectively (P = 0.16). The effect of titration strategy differed by baseline drug therapy, and was more effective in the metformin-treated individuals who experienced a HbA(1c) fall of 0.6 vs. 1.10% with pre-prandial vs. post-prandial titration (P for metformin-allocated group interaction = 0.043). The rate of hypoglycaemia did not differ by group.. In drug-naive individuals with Type 2 diabetes, similar HbA(1c) levels are achieved with repaglinide when dosing is adjusted according to either post-prandial or pre-prandial levels. Conversely, in metformin-treated individuals, repaglinide dosing according to post-prandial levels may lead to better glycaemic control than dosing according to pre-prandial levels.

Topics: Adult; Aged; Blood Glucose; Blood Specimen Collection; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Drug Monitoring; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Postprandial Period

The effect of repaglinide on insulin secretion and oxidative stress was evaluated in type 2 diabetic patients in a randomized, controlled, open-label trial. Forty-six patients were treated for 2 months with repaglinide, added to either diet (n=21) or metformin (n=25). A control group of 29 patients, matched for age, weight and glycaemic control, on either diet (n=13) or metformin (n=16) was also followed-up. Phases of insulin secretion (first-FPIS and second-SPIS) ware studied during IVGTT. Total serum antioxidant capacity and serum superoxide dismutase (SOD) activity were measured to assess oxidative stress. HbA(1c) decreased significantly in the repaglinide-treated group (P=0.01), the difference being significant compared with the control group (P=0.01). FPIS increased significantly after repaglinide (P<0.001). The area under the curve (AUC) for FPIS increased significantly (P<0.001), while the AUC for SPIS and for total insulin secretion did not change. Insulin secretion remained unchanged after 2 months in the control group. There was a significant increase after repaglinide in total serum antioxidant capacity (P<0.05) and serum SOD activity (P<0.0004); the difference compared to the control group being significant (P<0.002). Our results demonstrate the physiological effect of repaglinide on endogenous insulin secretion in a controlled, randomized, open-label study-there is a rise only in FPIS, which is the main beta-cell defect in type 2 diabetes mellitus. This improvement in glycaemic control was accompanied by a beneficial effect on oxidative stress in diabetes mellitus.

Topics: Carbamates; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Middle Aged; Oxidative Stress; Piperidines; Superoxide Dismutase; Treatment Outcome

The objective of this study was to investigate the pharmacokinetics of three different single doses (0.5, 1.0, and 2.0 mg) of repaglinide in healthy Caucasian and Japanese subjects. In this single-center, open-label, randomized, three-period crossover study, 27 healthy male subjects (15 Caucasian and 12 Japanese) each received three different single doses of repaglinide (0.5, 1.0, and 2.0 mg) at consecutive 24-hour intervals. Pharmacokinetic profiles, including area under the curve (AUC0-t), maximum serum concentration (Cmax), time to Cmax (tmax), and half-life (t1/2), were determined for each dose of repaglinide. The relative change in blood glucose level (RC1h) and area under the blood glucose curve (AUGC0-1) at 1 hour after dose were also measured. After oral dosing, both Cmax and AUC0-t increased linearly with dose within the 0.5- to 2.0-mg dose range, regardless of ethnic group. Both Cmax and AUC0-t were significantly higher in Japanese subjects than in Caucasian subjects. At each dose of repaglinide, Cmax and AUC were statistically significantly higher in Japanese than in Caucasian subjects (p = 0.0038 and 0.023, respectively). Discrepancies in body weight and body mass index (BMI) between Caucasian and Japanese subjects could not explain the between-group differences in Cmax or AUC0-t. Statistically significant differences in pharmacodynamic parameters (RC1h and AUGC0-1) were found between ethnic groups (p < 0.0001), the difference being more pronounced for RC1h than AUGC0-1. At a dose of 2.0 mg, the mean decrease in RC1h was 41% for Japanese subjects and 24% for Caucasian subjects. Hypoglycemic reactions were more common at the highest dose (2.0 mg), where they were observed more frequently in Japanese (7 cases) than in Caucasian subjects (4 cases). It was concluded that higher serum levels of repaglinide and greater reductions in blood glucose levels are found in Japanese than in Caucasian subjects following a single oral dose of repaglinide within the 0.5- to 2.0-mg dose range. Repaglinide is well tolerated in both ethnic groups. The results indicate that glycemic control targets may be achieved at lower doses within the recommended range (0.5-4.0 mg/meal) when repaglinide is used to treat Japanese patients in comparison to Caucasian patients.

Topics: Adolescent; Adult; Asian People; Carbamates; Cross-Over Studies; Dose-Response Relationship, Drug; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; White People

To evaluate the influence of renal impairment on the safety and efficacy of repaglinide in type 2 diabetic patients.. This multinational, open-label study comprised a 6-week run-in period, continuing prestudy antidiabetic medication, followed by a titration period (1-4 weeks) and a 3-month maintenance period. Patients with normal renal function (n = 151) and various degrees of renal impairment (n = 130) were treated with repaglinide (maximal dose of 4 mg, three times daily). Safety and efficacy assessments were performed at baseline (end of run-in) and at the end of study treatment.. The type and severity of adverse events during repaglinide treatment were similar to the run-in period. The number of patients with adverse events was not significantly related to renal function during run-in or repaglinide treatment. Percentage of patients with hypoglycemic episodes increased significantly (P = 0.007) with increasing severity of renal impairment during run-in but not during repaglinide treatment (P = 0.074). Metabolic control (HbA(1c) and fasting blood glucose) with repaglinide was unchanged from that on previous antidiabetic medication. Final repaglinide dose tended to be lower for patients with severe and extreme renal impairment than for patients with less severe renal impairment or normal renal function (P = 0.032).. Repaglinide has a good safety and efficacy profile in type 2 diabetic patients complicated by renal impairment and is an appropriate treatment choice, even for individuals with more severe degrees of renal impairment.

Topics: Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Female; Humans; Hypoglycemic Agents; Lipids; Male; Middle Aged; Piperidines; Severity of Illness Index

Our aim was to investigate possible interactions of gemfibrozil, itraconazole, and their combination with repaglinide.. In a randomised crossover study, 12 healthy volunteers received twice daily for 3 days either 600 mg gemfibrozil, 100 mg itraconazole (first dose 200 mg), both gemfibrozil and itraconazole, or placebo. On day 3 they ingested a 0.25 mg dose of repaglinide. Plasma drug and blood glucose concentrations were followed for 7 h and serum insulin and C-peptide concentrations for 3 h postdose.. Gemfibrozil raised the area under the plasma concentration-time curve (AUC) of repaglinide 8.1-fold (range 5.5- to 15.0-fold; p<0.001) and prolonged its half-life (t(1/2)) from 1.3 to 3.7 h (p<0.001). Although itraconazole alone raised repaglinide AUC only 1.4-fold (1.1- to 1.9-fold; p<0.001), the gemfibrozil-itraconazole combination raised it 19.4-fold (12.9- to 24.7-fold) and prolonged the t(1/2) of repaglinide to 6.1 h (p<0.001). Plasma repaglinide concentration at 7 h was increased 28.6-fold by gemfibrozil and 70.4-fold by the gemfibrozil-itraconazole combination (p<0.001). Gemfibrozil alone and in combination with itraconazole considerably enhanced and prolonged the blood glucose-lowering effect of repaglinide; i.e., repaglinide became a long-acting and stronger antidiabetic.. Clinicians should be aware of this previously unrecognised and potentially hazardous interaction between gemfibrozil and repaglinide. Concomitant use of gemfibrozil and repaglinide is best avoided. If the combination is considered necessary, repaglinide dosage should be greatly reduced and blood glucose concentrations carefully monitored.

Topics: Adult; Antifungal Agents; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Biotransformation; Blood Glucose; C-Peptide; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Drug Interactions; Female; Gemfibrozil; Half-Life; Humans; Hypoglycemic Agents; Hypolipidemic Agents; Insulin; Itraconazole; Male; Piperidines

Repaglinide and glimepiride are relatively new oral hypoglycemic agents. Few data are available concerning their effects on metabolic parameters other than measures of glycemic control.. In addition to assessing the effects of repaglinide and glimepiride on glycemic control in patients with type 2 diabetes mellitus, this study also examined the effects of these agents on 3 metabolic parameters known to be cardiovascular risk factors--lipoprotein(a) (Lp[a]), plasminogen activator inhibitor-1 (PAI-1), and homocysteine (Hcy).. This randomized, placebo-controlled, double-blind trial was conducted at a single center in Italy. Eligible patients were nonsmokers; had no hypertension or coronary heart disease; were taking no hypolipidemic drugs, diuretics, beta-blockers, or thyroxin; and had normal renal function. After an initial 4-week placebo washout period, patients were randomized to receive repaglinide 1 mg/d or glimepiride 1 mg/d. The dose of study drug was optimized over an 8-week titration period, which was followed by a 12-month treatment period. Measures of glycemic control (glycated hemoglobin [HbA1c], fasting plasma glucose [FPG], postprandial plasma glucose [PPG], fasting plasma insulin [FPI], postprandial plasma insulin [PPI]) and the other metabolic parameters of interest were assessed after 6 and 12 months of treatment.. One hundred twenty-four patients (63 women, 61 men) completed the study, 62 in each treatment group. There were no significant differences in demographic characteristics between groups. After 6 and 12 months of treatment, FPG levels and HbA1c values were significantly reduced from baseline in both groups (6 months, P < 0.05; 12 months, P < 0.01). After 6 months, PPG levels were significantly decreased only in the repaglinide group (P < 0.05 vs baseline); at 12 months, however, PPG levels were significantly reduced from baseline in both groups (P < 0.01 repaglinide, P < 0.05 glimepiride). No significant changes from baseline in FPI or PPI levels were seen in either group at 6 months, although FPI levels were significantly increased in the repaglinide group at 12 months (P < 0.05). Repaglinide significantly lowered levels of Lp(a), PAI-1, and Hcy after 12 months (all, P < 0.05 vs baseline). Glimepiride significantly lowered levels of Lp(a) and Hcy after 6 months (both, P < 0.05 vs baseline) and levels of Lp(a) (P < 0.01 vs baseline), Hcy (P < 0.01 vs baseline), and PAI-1 (P < 0.05 vs baseline) after 12 months.. Repaglinide and glimepiride improved glycemic control and reduced levels of other metabolic parameters of interest in this population of patients with type 2 diabetes. It is possible that the reductions in Lp(a), PAI-1, and Hcy were the result of improved glucose metabolism; however, the possibility that repaglinide and glimepiride may have a direct effect on these parameters should not be excluded.

Topics: Blood Glucose; Blood Pressure; Carbamates; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Homocysteine; Humans; Hypoglycemic Agents; Lipoprotein(a); Male; Middle Aged; Piperidines; Plasminogen Activator Inhibitor 1; Risk Factors; Sulfonylurea Compounds; Time Factors; Treatment Outcome

To compare glycaemic control and cardiovascular risk profile in patients with type 2 diabetes following 12 months' treatment with either repaglinide or metformin.. This was an open uncontrolled randomised study in n=112 patients with inadequately controlled type 2 diabetes not previously treated with oral hypoglycaemic agents. Patients beginning treatment with either repaglinide or metformin entered an 8-week titration period (to optimise dosage: repaglinide, 2-4 mg/day; metformin, 1500-2500 mg/day) followed by a 12-month treatment period. Glycaemic control and cardiovascular risk factors were determined at baseline and at the end of the treatment period.. Mean (S.D.) final drug doses were 3 (+/-1) mg/day in the repaglinide group and 2000 (+/-500) mg/day in the metformin group. Significant improvements in glycaemic control [glycated haemoglobin, fasting and 2-h postprandial plasma glucose (PPG)] were demonstrated in both treatment groups. The decrease in PPG was significantly greater in the repaglinide group (P<0.05). During the treatment period, fasting plasma insulin (FPI) decreased significantly in both groups, more so with metformin (P<0.05). Two-hour postprandial plasma insulin (PPI) levels decreased only in the metformin group (P<0.05). Significant improvements between baseline and final visit were demonstrated in one or both groups in the following cardiovascular risk factors: total cholesterol, low-density lipoprotein cholesterol (LDL-C), triglycerides, plasminogen activator inhibitor, lipoprotein(a) and homocysteine. No changes were observed in high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I, apolipoprotein B, fibrinogen, body mass index (BMI) or blood pressure.. The use of repaglinide or metformin in drug therapy-nai;ve patients with type 2 diabetes over a 12-month period is associated with improvements in both glycaemic control and cardiovascular risk profile. The latter cannot necessarily be attributed to the pharmacotherapy per se, but provides reassurance in the context of initiating oral hypoglycaemic drug therapy with these agents.

Topics: Blood Glucose; Carbamates; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Insulin; Lipoproteins; Male; Metformin; Middle Aged; Piperidines; Prospective Studies; Risk Factors; Triglycerides

This prospective, 16-week, randomised, double-blind, parallel-group study assessed the differential impact of the prandial glucose regulating oral hypoglycaemic drug, repaglinide, and placebo upon perceptions of quality of life (QoL) and treatment satisfaction in pharmacotherapy-naive patients with Type 2 diabetes. In addition, the study assessed whether these outcomes were influenced by the patients' level of glycaemic control. A total of 253 patients were randomised in a 2:1 ratio of repaglinide: placebo, with doses taken flexibly with main meals (2-4 per day), whenever they were eaten. Repaglinide was initiated at 0.5 mg per meal, increased to 1 mg after 4 weeks if fasting plasma glucose exceeded 7.8 mmol/l. QoL and treatment satisfaction outcomes were compared using generic and disease-specific self-assessment measures, previously applied in diabetes: the WHO Wellbeing Questionnaire (WHO-WBQ), WHO Diabetes Treatment Satisfaction Questionnaire (WHO-DTSQ) and EuroQoL EQ-5D. Over the trial period, repaglinide-treated patients reported a significant 9% improvement in (WHO-DTSQ) treatment satisfaction score (p < 0.05). No significant increase was associated with placebo. The correlation between decrease in glycated haemoglobin (HbA1c) and increase in treatment satisfaction (WHO-DTSQ) was -0.22 (p < 0.01). Scores obtained with the other measures did not change significantly during the trial in either group, but the cohort exhibited only a slight reduction in wellbeing (WHO-WBQ) and health status (EQ-5D) at baseline compared with the background population. In conclusion, flexible mealtime dosing with oral medication appears to be well accepted by pharmacotherapy-naïve patients with Type 2 diabetes. The results suggest that repaglinide provides a higher level of treatment satisfaction than placebo, and this may in part relate to improved glycaemic control.

Topics: Carbamates; Diabetes Mellitus, Type 2; Double-Blind Method; Health Status; Health Status Indicators; Humans; Hypoglycemic Agents; Patient Satisfaction; Piperidines; Prospective Studies; Quality of Life; Surveys and Questionnaires; Translating

The object of this study was to analyze drug interactions between repaglinide, a short-acting insulin secretagogue, and five other drugs interacting with CYP3A4: ketoconazole, rifampicin, ethinyloestradiol/levonorgestrel (in an oral contraceptive), simvastatin, and nifedipine. In two open-label, two-period, randomized crossover studies, healthy subjects received repaglinide alone, repaglinide on day 5 of ketoconazole treatment, or repaglinide on day 7 of rifampicin treatment. In three open-label, three-period, randomized crossover studies, healthy subjects received 5 days of repaglinide alone; 5 days of ethinyloestradiol/levonorgestrel, simvastatin, or nifedipine alone; or 5 days of repaglinide concomitant with ethinyloestradiol/levonorgestrel, simvastatin, or nifedipine. Compared to administration of repaglinide alone, concomitant ketoconazole increased mean AUC0-infinity for repaglinide by 15% and mean Cmax by 7%. Concomitant rifampicin decreased mean AUC0-infinity for repaglinide by 31% and mean Cmax by 26%. Concomitant treatment with CYP3A4 substrates altered mean AUC0-5 h and mean Cmax for repaglinide by 1% and 17% (ethinyloestradiol/levonorgestrel), 2% and 27% (simvastatin), or 11% and 3% (nifedipine). Profiles of blood glucose concentration following repaglinide dosing were altered by less than 8% by both ketoconazole and rifampicin. In all five studies, most adverse events were related to hypoglycemia, as expected in a normal population given a blood glucose regulator. The safety profile of repaglinide was not altered by pretreatment with ketoconazole or rifampicin or by coadministration with ethinyloestradiol/levonorgestrel. The incidence of adverse events increased with coadministration of simvastatin or nifedipine compared to either repaglinide or simvastatin/nifedipine treatment alone. No clinically relevant pharmacokinetic interactions occurred between repaglinide and the CYP3A4 substrates ethinyloestradiol/levonorgestrel, simvastatin, or nifedipine. The pharmacokinetic profile of repaglinide was altered by administration of potent inhibitors or inducers, such as ketoconazole or rifampicin, but to a lesser degree than expected. These results are probably explained by the metabolic pathway of repaglinide that involves other enzymes than CYP3A4, reflected to some extent by a small change in repaglinide pharmacodynamics. Thus, careful monitoring of blood glucose in repaglinide-treated patients receiving strong inhibitors or inducers of CYP3A4 is

Topics: Adult; Area Under Curve; Blood Glucose; Carbamates; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Drug Interactions; Female; Half-Life; Humans; Hypoglycemic Agents; Ketoconazole; Male; Piperidines; Rifampin; Simvastatin

An open-label, parallel-group, randomized, multicenter trial was conducted to compare efficacy and safety of repaglinide versus nateglinide, when used in a combination regimen with metformin for treatment of type 2 diabetes.. Enrolled patients (n = 192) had HbA(1c) >7% and < or =12% during previous treatment with a sulfonylurea, metformin, or low-dose Glucovance (glyburide < or =2.5 mg, metformin < or =500 mg). After a 4-week metformin run-in therapy period (doses escalated to 1,000 mg b.i.d.), patients were randomized to addition of repaglinide (n = 96) (1 mg/meal, maximum 4 mg/meal) or nateglinide (n = 96) (120 mg/meal, reduced to 60 mg if needed) to the regimen for 16 weeks. Glucose, insulin, and glucagon were assessed after a liquid test meal at baseline and week 16.. Final HbA(1c) values were lower for repaglinide/metformin treatment than for nateglinide/metformin (7.1 vs. 7.5%). Repaglinide/metformin therapy showed significantly greater mean reductions of HbA(1c) (-1.28 vs. -0.67%; P < 0.001) and of fasting plasma glucose (FPG) (-39 vs. -21 mg/dl; P = 0.002). Self-monitoring of blood glucose profiles were significantly lower for repaglinide/metformin before breakfast, before lunch, and at 2:00 A.M. Changes in the area under the curve of postprandial glucose, insulin, or glucagon peaks after a test meal were not significantly different for the two treatment groups during this study. Median final doses were 5.0 mg/day for repaglinide and 360 mg/day for nateglinide. Safety assessments were comparable for the two regimens.. The addition of repaglinide to metformin therapy resulted in reductions of HbA(1c) and FPG values that were significantly greater than the reductions observed for addition of nateglinide.

Topics: Area Under Curve; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Male; Metformin; Middle Aged; Nateglinide; Phenylalanine; Piperidines; Postprandial Period; Safety

The effect of acute repaglinide administration (2 mg) on postprandial glycaemia and lipaemia has been examined in 20 subjects with type 2 diabetes mellitus. Each subject received in the morning, after a 12 to 14 h fast, a standard mixed meal (total energy 783 kcal), preceded by one tablet of 2 mg repaglinide or placebo. Chylomicrons and chylomicron-deficient plasma were prepared by ultracentrifugation. Triglyceride levels in CM fraction (CM-triglycerides) in total plasma as well as in CM-deficient plasma (non-CM-triglycerides) were determined. A significant reduction in postprandial glycaemia was observed after repaglinide administration compared to placebo ( p < 0.001). Plasma concentrations of total triglycerides, CM-triglycerides, non-CM-triglycerides, free fatty acids and the other plasma lipids measured, were not significantly different between the two phases of the study. It is concluded that, in contrast to sulphonylureas, acute repaglinide administration does not improve postprandial lipaemia in patients with type 2 diabetes.

Topics: Analysis of Variance; Blood Glucose; C-Peptide; Carbamates; Cholesterol; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Glycated Hemoglobin; Humans; Hyperlipidemias; Hypoglycemic Agents; Insulin; Kinetics; Piperidines; Postprandial Period; Triglycerides

Our objective was to investigate the effects of genetic polymorphisms of cytochrome P450 (CYP) 2C8 on the pharmacokinetics and pharmacodynamics of the meglitinide analog antidiabetic drug repaglinide.. We genotyped 28 healthy volunteers who had participated in our pharmacokinetic studies on repaglinide for variant alleles of the CYP2C8 gene. Each subject ingested a 0.25-mg dose of repaglinide, and plasma drug and blood glucose concentrations were monitored for 7 hours after dosing.. There were 19 subjects (68%) with the CYP2C8*1/*1 genotype (wild type), 6 subjects (21%) with the CYP2C8*1/*3 genotype, and 3 subjects (11%) with the CYP2C8*1/*4 genotype. In the 3 genotypic groups, the mean +/- SD area under the plasma repaglinide concentration-time curve from time 0 to infinity [AUC(0- infinity )] was 5.8 +/- 2.5 ng. h/mL for CYP2C8*1/*1, 3.6 +/- 0.9 ng. h/mL for CYP2C8*1/*3, and 5.1 +/- 3.6 ng. h/mL for CYP2C8*1/*4. The mean AUC(0- infinity ) of repaglinide was 45% (P <.005) lower and the peak concentration in plasma was 39% lower (P <.05) in subjects with the CYP2C8*1/*3 genotype compared with those with the CYP2C8*1/*1 genotype. No statistically significant differences were found in the blood glucose response to repaglinide between the genotypes.. Unexpectedly, the CYP2C8*3 variant allele was associated with reduced plasma concentrations of repaglinide. The effects of CYP2C8 polymorphisms on the pharmacokinetics of CYP2C8 substrates warrant further study.

Topics: Adult; Alleles; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Blood Glucose; Carbamates; Cytochrome P-450 CYP2C8; Female; Genotype; Half-Life; Humans; Hypoglycemic Agents; Linear Models; Male; Piperidines; Polymorphism, Genetic

This open-label randomized controlled clinical trial compared the effect on glycaemic control and weight gain of repaglinide vs. gliclazide combined with bedtime NPH insulin in patients with Type 2 diabetes inadequately controlled with oral hypoglycaemic therapy [HbA1c>7.0% (DCCT aligned assay, normal range 4.6-6.2%)].. Eighty subjects with Type 2 diabetes were randomized to 13 weeks' open-label treatment with repaglinide 4 mg t.i.d. or gliclazide 160 mg b.i.d. in combination with bedtime NPH insulin (initial dose 0.5 units/kg). The fasting blood glucose (FBG) target was < or =6.0 mmol/l.. Baseline characteristics were similar for age, sex, weight, BMI, FBG and HbA1c. Glycaemic control improved similarly in both groups-insulin/gliclazide by (mean) 1.0%, from 9.2 to 8.2% (P=0.001) and by 0.9%, from 9.4 to 8.5% in the insulin/repaglinide group (P=0.005) (P=0.83 between groups). Weight gain averaged (mean +/- sem) 4.1 +/- 0.5 and 3.4 +/- 0.4 kg in the insulin/gliclazide and insulin/repaglinide groups, respectively (P<0.0001 for both groups from baseline) (P=0.29 between groups). The mean number of hypoglycaemic episodes experienced per patient was 2.95 +/- 0.82 (insulin/gliclazide) and 2.3 +/- 0.52 (insulin/repaglinide) (P=0.81 between groups). Both treatments were associated with significant improvements in Diabetes Treatment Satisfaction [Diabetes Treatment Satisfaction Questionnaire-potential range 0 (min) to 36 (max)]; in the insulin/gliclazide group, by 4.9 +/- 1.1 points to 33.3 +/- 0.6 (P<0.0001) and by 3.0 +/- 0.9 points to 34.6 +/- 0.4 (P=0.0006) in the insulin/repaglinide group (P=0.29 between groups).. Over 13 weeks, both repaglinide and gliclazide, when combined with bedtime NPH insulin produce similar significant improvements in glycaemic control (-1%) and similar weight gain.

Topics: Administration, Oral; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Gliclazide; Hemoglobin A; Humans; Hypoglycemic Agents; Insulin, Isophane; Male; Metformin; Middle Aged; Patient Satisfaction; Piperidines; Surveys and Questionnaires; Weight Gain

To compare the effects of repaglinide, glipizide, and glibenclamide on insulin secretion and postprandial glucose after a single standard 500-kcal test meal.. A total of 12 type 2 diabetic patients with early diabetes (mean HbA(1c) of 6.1%) and 12 matched control subjects were enrolled in this randomized, double-blind, crossover trial. Subjects received placebo, 2 mg repaglinide, 5 mg glipizide, and 5 mg glibenclamide in a random fashion during the trial. Administration of each drug was followed by a single standard 500-kcal test meal. A washout period of 7-12 days existed between the four study visits.. All three drugs were equally effective on the total prandial insulin secretion (area under the curve [AUC] -15 to 240 min). However, clear differences were noted in the early insulin secretion (AUC -15 to 30 min); both repaglinide and glipizide increased secretion in nondiabetic subjects by approximately 61 and 34%, respectively, compared with placebo. In the diabetic patients, the difference versus placebo was 37 and 47%, respectively. The difference between glipizide and glibenclamide reached significance in both groups of subjects, whereas repaglinide was more effective than glibenclamide only in the healthy nondiabetic subject group. All three drugs were effective in decreasing total glucose AUC in the nondiabetic and diabetic population. In the nondiabetic subjects, however, repaglinide was significantly more effective than glibenclamide. The differences disappeared in the diabetic subjects, probably as a result of increased prevalence of insulin resistance in this group.. Repaglinide and glipizide but not glibenclamide significantly enhanced the early insulin secretion in both nondiabetic and diabetic subjects with preserved beta-cell function after a single standard meal.

Topics: Aged; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 2; Double-Blind Method; Eating; Female; Glipizide; Glyburide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Male; Middle Aged; Piperidines

This study compared treatment with a prandial glucose regulator (repaglinide) and a sulphonylurea (glibenclamide) in Muslim Type 2 diabetic patients who practice Ramadan fasting. Two hundred and thirty-five patients, previously treated with a sulphonylurea, were randomised to receive either repaglinide (n=116, preprandially three-times daily) or glibenclamide (n=119, preprandially once- or twice-daily) 6 weeks before Ramadan. During Ramadan, patients changed their eating pattern to two meals daily, and the daily dose of repaglinide was redistributed to two preprandial doses. After Ramadan, patients resumed their regular meal pattern and treatment dosage for 4 weeks. During Ramadan, a statistically significant reduction in mean serum fructosamine concentration from baseline was observed in the repaglinide group (-16.9+/-4.9 micromol/l, -3.8%, P<0.05) but not the glibenclamide group (-6.9+/-4.8 micromol/l, -0.8%). Difference in change in HbA(1c) from baseline was not statistically significant between groups. The number of hypoglycaemic events with midday blood glucose <4.5 mmol/l was significantly lower in the repaglinide group (2.8%) than the glibenclamide group (7.9%) (P=0.001). Apart from hypoglycaemia, both treatments were equally well tolerated. Type 2 diabetic Muslims using prandial repaglinide showed a trend towards better glycaemic control and had a lower frequency of hypoglycaemia than patients using glibenclamide during Ramadan.

Topics: Biomarkers; Carbamates; Diabetes Mellitus, Type 2; Fasting; Feeding Behavior; Female; Fructosamine; Glyburide; Humans; Hypoglycemia; Hypoglycemic Agents; Islam; Malaysia; Male; Middle Aged; Piperidines; Risk Factors; Safety; Time Factors

To compare the effect on glycemic control and weight gain of repaglinide versus metformin combined with bedtime NPH insulin in patients with type 2 diabetes.. A total of 80 subjects treated with 850 or 1,000 mg t.i.d. metformin combined with bedtime NPH insulin were randomized to 13 weeks of open-label treatment with 4 mg t.i.d. repaglinide (n = 39) or metformin (dose unchanged) (n = 41). Insulin dose was titrated at the clinician's discretion, aiming for a fasting blood glucose (FBG) < or =6.0 mmol/l.. Baseline age, diabetes duration, insulin requirement, weight, BMI, FBG, and HbA(1c) (Diabetes Control and Complications Trial-aligned assay, normal range 4.6-6.2%) were similar. Glycemic control improved (nonsignificantly) with insulin/metformin by (mean) 0.4%, from 8.4 to 8.1% (P = 0.09) but deteriorated with insulin/repaglinide by (mean) 0.4%, from 8.1 to 8.6% (P = 0.03; P = 0.005 between groups). Weight gain was less with insulin/metformin: 0.9 +/- 0.4 kg (means +/- SE) (P = 0.01) versus 2.7 +/- 0.4 kg (P < 0.0001) (P = 0.002 between groups). The Diabetes Treatment Satisfaction Questionnaire score (potential range 0 [minimum] to 36 [maximum]) increased from 32.4 +/- 0.8 to 34.1 +/- 0.5 (P = 0.01) with insulin/metformin but decreased from 32.5 +/- 0.9 to 29.1 +/- 1.3 (P < 0.002) with insulin/repaglinide.. Combined with bedtime NPH insulin, metformin provides superior glycemic control to repaglinide with less weight gain and improved diabetes treatment satisfaction.

Topics: Blood Glucose; Carbamates; Creatinine; Diabetes Mellitus, Type 2; Drug Administration Schedule; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Insulin, Isophane; Male; Metformin; Middle Aged; Piperidines; Time Factors

Repaglinide, a novel antidiabetic agent that has a rapid onset and short duration of action, was developed for mealtime dosing. The purpose of this pharmacodynamic study was to validate a prandial regimen of repaglinide by comparing meal-related dosing with a regimen in which the same total daily dose was divided into only two doses at morning and evening meals.. The study was a double-blind, randomized, parallel-group trial in 19 antidiabetic agent-naive subjects with type 2 diabetes (mean age 58 years, known duration of diabetes 3.5 years, HbA(1c) 7.3%, and BMI 32 kg/m(2)). Patients were randomly assigned to receive repaglinide either before each of the three main meals or before breakfast and before the evening meal. Patients in both groups received the same total daily dose of repaglinide. Twenty-four hour profiles of blood glucose, plasma insulin, and plasma C-peptide concentrations were measured at baseline and after 4 weeks of treatment.. Repaglinide increased postprandial insulin levels and markedly reduced postprandial glucose levels relative to baseline in both groups. Significant reductions were also recorded in fasting blood glucose and HbA(1c) levels. The repaglinide regimen, in which a dose was taken before each main meal, was more effective in improving glycemic control (including postprandial glucose and HbA(1c) levels) than the same total dose of repaglinide divided into morning and evening mealtime doses.. These data support the strategy of mealtime dosing with repaglinide. The improvements in glycemic control observed in these patients are encouraging. In addition to classic parameters of glycemic control, improvements in postprandial glucose excursions may prove to be important because postprandial hyperglycemia has been suggested to be an independent risk factor for cardiovascular disease in diabetes.

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Double-Blind Method; Eating; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Middle Aged; Piperidines; Postprandial Period

To develop a predictive population pharmacokinetic/ pharmacodynamic (PK/PD) model for repaglinide (REP), an oral hypoglycemic agent, using artificial neural networks (ANNs).. REP, glucose concentrations, and demographic data from a dose ranging Phase 2 trial were divided into a training set (70%) and a test set (30%). NeuroShell Predictor was used to create predictive PK and PK/PD models using population covariates: evaluate the relative significance of different covariates; and simulate the effect of covariates on the PK/PD of REP. Predictive performance was evaluated by calculating root mean square error and mean error for the training and test sets. These values were compared to naive averaging (NA) and randomly generated numbers (RN).. Covariates found to have an influence on PK of REP include dose, gender. race, age, and weight. Covariates affecting the glucose response included dose, gender, and weight. These differences are not expected to be clinically significant.. We came to the following three conclusions: 1) ANNs are more precise than NA and RN for both PK and PD; 2) the bias was acceptable for ANNs as compared with NA and RN; and 3) neural networks offer a quick and simple method for predicting, for identifying significant covariates, and for generating hypotheses.

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Male; Neural Networks, Computer; Piperidines; Predictive Value of Tests

This double-blind randomized placebo-controlled parallel group study assessed the efficacy and safety (with particular regard to body weight and hypoglycemia) of repaglinide when used in a flexible mealtime dosing regimen in a situation close to everyday clinical practice.. A total of 408 patients with type 2 diabetes considered poorly controlled by diet, but without a history of previous antidiabetic medication, were randomized to receive 0.5 mg repaglinide at mealtimes (increased to 1 mg after 4 weeks depending on blood glucose response) or placebo for 16 weeks. Patients were free to choose a flexible meal pattern, adjusting the dosing schedule from two to four preprandial doses per day in accordance with a "one meal, one dose; no meal, no dose" principle. Additional snacks were not a requirement of the treatment schedule.. Treatment with repaglinide significantly improved glycemic control with respect to baseline and placebo, reducing HbA1c by 1.14% from baseline and fasting plasma glucose by 1.8 mmol/l. Improvement in glycemic control was independent of the meal pattern adopted by patients, including those most commonly taking two or four meals daily, with no correlation between meal pattern and risk of hypoglycemia. The improvement in glycemic control was also independent of degree of obesity and age < or =65 or >65 years. There was no significant body weight increase in the repaglinide group.. Mealtime dosing with repaglinide is effective in improving overall glycemic control in type 2 diabetic patients for which control is suboptimal using diet alone. Patients are able to vary their meal pattern from a conventional regimen of three meals daily without compromising control or increasing the risk of adverse events.

Topics: Aged; Blood Glucose; Body Weight; Carbamates; Diabetes Mellitus, Type 2; Diet; Double-Blind Method; Fasting; Female; Food; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Placebos

This study was designed to compare the pharmacodynamic effects of single doses of nateglinide (A-4166), repaglinide, and placebo on mealtime insulin secretion and glycemic control in healthy subjects.. Fifteen healthy volunteers participated in this open-label five-period crossover study. They received single 10-min preprandial doses of 120 mg nateglinide, 0.5 or 2 mg repaglinide, or placebo or 1 min preprandially of 2 mg repaglinide. Subjects received each dose only once, 48 h apart. Pharmacodynamic and pharmacokinetic assessments were performed from 0 to 12 h postdose.. Nateglinide induced insulin secretion more rapidly than 2 and 0.5 mg repaglinide and placebo (10 min preprandial), with mean rates of insulin rise of 2.3, 1.3, 1.15, and 0.8 microU x ml(-1) x min(-1), respectively, over the 0- to 30-min postmeal interval. After peaking, insulin concentrations decreased rapidly in the nateglinide-treated group and were similar to placebo within 2 h postdose. After 2 mg repaglinide, peak insulin concentrations were delayed and returned to baseline more slowly than with nateglinide treatment. Nateglinide treatment produced lower average plasma glucose concentrations in the 0- to 2-h postdose interval than either dose of repaglinide and placebo (P < 0.05 vs. 0.5 mg repaglinide and placebo). Plasma glucose concentrations returned more rapidly to predose levels with nateglinide treatment than with either dose of repaglinide. Treatment with repaglinide produced a sustained hypoglycemic effect up to 6 h postdose.. In this single-dose study in nondiabetic volunteers, nateglinide provided a more rapid and shorter-lived stimulation of insulin secretion than repaglinide, resulting in lower meal-related glucose excursions. If similar results are observed in diabetes, nateglinide may produce a more physiological insulin secretory response with the potential for a reduced risk of postabsorptive hypoglycemia.

Topics: Adolescent; Adult; Blood Glucose; Body Mass Index; Body Weight; Carbamates; Cross-Over Studies; Cyclohexanes; Female; Food; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Kinetics; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines; Placebos; Time Factors

The primary objective of this single-centre, open-label, parallel-group study was to evaluate the pharmacokinetics and safety profile of the prandial glucose regulator repaglinide, following single and multiple dosing, in patients with type 2 diabetes with and without varying degrees of renal impairment.. The study comprised three screening visits, followed by a 7-day inpatient period. Thirty-four patients, with normal renal function (n = 12), mild-to-moderate renal dysfunction (n = 12) or severe renal dysfunction (n = 10), received a single 2-mg dose of repaglinide on day 1, followed by preprandial 2-mg doses with main meals (breakfast, lunch and dinner) on each of days 2-4. A final 2-mg dose of repaglinide was administered on day 5.. Patients with mild-to-moderate renal impairment showed no significant differences in the pharmacokinetics of repaglinide, compared with patients with normal renal function. In the group of patients with severe renal dysfunction, the main pharmacokinetic finding was a longer half-life after multiple dosing. Rates of minor hypoglycaemia were similar in patients with severe, mild-to-moderate and no renal dysfunction. No major hypoglycaemic episodes occurred.. Patients with type 2 diabetes and mild or moderate impairment of renal function may be treated with repaglinide without special precautions. If repaglinide is used in patients with severely impaired renal function, dose adjustment may be necessary if indicated by blood glucose measurements.

Topics: Aged; Analysis of Variance; Area Under Curve; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Female; Half-Life; Humans; Hypoglycemic Agents; Male; Metabolic Clearance Rate; Middle Aged; Piperidines; Renal Insufficiency

Our objective was to study the effects of the macrolide antibiotic clarithromycin on the pharmacokinetics and pharmacodynamics of repaglinide, a novel short-acting antidiabetic drug.. In a randomized, double-blind, 2-phase crossover study, 9 healthy volunteers were treated for 4 days with 250 mg oral clarithromycin or placebo twice daily. On day 5 they received a single dose of 250 mg clarithromycin or placebo, and 1 hour later a single dose of 0.25 mg repaglinide was given orally. Plasma repaglinide, serum insulin, and blood glucose concentrations were measured up to 7 hours.. Clarithromycin increased the mean total area under the concentration-time curve of repaglinide by 40% (P <.0001) and the peak plasma concentration by 67% (P <.005) compared with placebo. The mean elimination half-life of repaglinide was prolonged from 1.4 to 1.7 hours (P <.05) by clarithromycin. Clarithromycin increased the mean incremental area under the concentration-time curve from 0 to 3 hours of serum insulin by 51% (P <.05) and the maximum increase in the serum insulin concentration by 61% (P <.01) compared with placebo. No statistically significant differences were found in the blood glucose concentrations between the placebo and clarithromycin phases.. Even low doses of the cytochrome P4503A4 (CYP3A4) inhibitor clarithromycin increase the plasma concentrations and effects of repaglinide. Concomitant use of clarithromycin or other potent inhibitors of CYP3A4 with repaglinide may enhance its blood glucose-lowering effect and increase the risk of hypoglycemia.

Topics: Adult; Analysis of Variance; Anti-Bacterial Agents; Blood Glucose; Carbamates; Clarithromycin; Cross-Over Studies; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Double-Blind Method; Drug Administration Schedule; Female; Humans; Hypoglycemic Agents; Insulin; Male; Mixed Function Oxygenases; Piperidines; Reference Values; Time Factors

To evaluate the long-term effectiveness and safety of repaglinide, a novel prandial glucose regulator, in comparison with glipizide in the treatment of patients with Type 2 diabetes.. Diet or tablet-treated patients with Type 2 diabetes (n = 256; age 40-75 years, body mass index (BMI) 20-35 kg/m2, HbA1c 4.2-12.8%), without signs of severe microvascular or macrovascular complications, were included in this double-blind, multicentre, parallel-group comparative trial. Patients were randomized at a 2:1 ratio to repaglinide, 1-4 mg at mealtimes, or glipizide, 5-15 mg daily.. Changes in fasting blood glucose (FBG) and HbA1c during the 12 months of treatment showed a significant difference in favour of repaglinide. In oral hypoglycaemic agents (OHA)-naive patients, HbA1c decreased in the repaglinide and glipizide groups by 1.5% and 0.3%, respectively (P < 0.05 between groups). Fasting blood glucose decreased in the repaglinide group by 2.4 mmol/l and increased in the glipizide group by 1.0 mmol/l (P < 0.05 between groups). In the study population as a whole, repaglinide was able to maintain glycaemic control (HbA1c level) during the 1-year study period, whereas control deteriorated significantly with glipizide. Change in HbA1c from baseline was significantly better with repaglinide than with glipizide after 12 months (P < 0.05). In addition, FBG deteriorated significantly in the glipizide group compared with the repaglinide group (P < 0.05). No patients in either group experienced a major hypoglycaemic event; the number of patients experiencing minor hypoglycaemia was similar in the repaglinide and glipizide groups (15% and 19%, respectively).. Repaglinide, given as a prandial glucose regulator, is shown to be an effective and safe treatment of patients with Type 2 diabetes, and is better than glipizide in controlling HbA1c and FBG levels, overall, and in OHA-naive patients.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Carbamates; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Double-Blind Method; Fasting; Female; Glipizide; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Piperidines

The prandial glucose regulator repaglinide has a rapid onset of action, a short half-life and is metabolised mainly by the liver. Here we report the findings of a 10-week, double-blind, parallel, placebo controlled, randomised trial with repaglinide in 25 diet-treated, sulphonylurea-naïve patients with Type 2 diabetes. Repaglinide was titrated, based on capillary blood glucose, from 0.5 mg to a maximum of 4 mg, preprandially with breakfast and dinner. After 10 weeks, repaglinide was associated with a decrease in HbA(1c) of 2.3%Hb relative to the placebo group (P=0.018). This reflected a 30% decrease within the repaglinide group from a mean HbA(1c) of 7.0 to 4.9%Hb (P<0.002). Repaglinide was also associated with a decrease in fructosamine, by 0.88 mmol/l, relative to placebo (P<0.001), with a 20% decrease (from 3.80 to 3.04 mmol/l) within the repaglinide group (P<0.001). Fasting and postprandial blood glucose concentrations decreased in association with repaglinide by 3.6 and 6.4 mmol/l, respectively, relative to placebo (P<0.001 in each case). Within the repaglinide group fasting and postprandial blood glucose decreased by 3.9 and 6.2 mmol/l, respectively (P<0.001 in each case). The number of patients reporting hypoglycaemia in the repaglinide group was similar to placebo (15 vs. 20, respectively; NS). Test meal assessments confirmed that repaglinide effectively controls glucose levels by stimulating mealtime insulin secretion. Fasting serum insulin concentration was not raised compared to baseline or placebo during repaglinide therapy, albeit that fasting glucose levels were decreased by repaglinide. Twice-daily meal-related insulin secretagogue therapy with repaglinide, a new short and rapid-acting prandial glucose regulator, is capable of improving all measures of glycaemic control without increased hypoglycaemia or fasting hyperinsulinaemia.

Topics: Area Under Curve; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Administration Schedule; Fasting; Fructosamine; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Middle Aged; Piperidines; Placebos; Postprandial Period; Time Factors

In this 24-week multicenter, double-blind, randomized, fixed-dose trial, 361 patients having type 2 diabetes received daily preprandial treatment with placebo (n = 75), repaglinide 1 mg (n = 140), or repaglinide 4 mg (n = 146). By a last-observation carried-forward calculation, repaglinide 1 mg or 4 mg treatment decreased mean fasting plasma glucose (FPG) values (by -47 mg/dL or -49 mg/dL) while the placebo group had increased FPG values (by 19 mg/dL). For the repaglinide treatment groups at the end of the study, changes in HbA1c from baseline values ranged from 1.8 to 1.9 percentage points lower than the placebo group. There were no events of severe hypoglycemia. Nearly all hypoglycemic symptom episodes had blood glucose levels above 45 mg/dL. Repaglinide was well tolerated in a preprandial fixed-dose regimen of 1 mg or 4 mg, assigned without adjustment for clinical parameters.

Topics: Adult; Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Double-Blind Method; Fasting; Female; Humans; Hypoglycemic Agents; Male; Middle Aged; Patient Dropouts; Piperidines; Time Factors; Treatment Outcome

Repaglinide is a novel insulin secretagogue developed in response to the need for a fast-acting, oral prandial glucose regulator for the treatment of type 2 (non-insulin-dependent) diabetes mellitus. Repaglinide is metabolized mainly in the liver; its pharmacokinetics may therefore be altered by hepatic dysfunction. This open, parallel-group study compared the pharmacokinetics and tolerability of a single 4 mg dose of repaglinide in healthy subjects (n = 12) and patients with chronic liver disease (CLD) (n = 12). Values for AUC and Cmax were significantly higher in CLD patients compared with healthy subjects, and the MRT was prolonged in CLD patients. Values for tmax did not differ between the groups, but t1/2 was significantly prolonged in CLD patients compared with previously determined values in healthy subjects. AUC was inversely correlated with caffeine clearance in CLD patients but not in healthy subjects. Blood glucose profiles were similar in both groups. Adverse events (principally hypoglycemia) were similar in the two groups; none was serious. Repaglinide clearance is significantly reduced in patients with hepatic impairment; the agent should be used with caution in this group.

Topics: Adult; Blood Glucose; Blood Proteins; Caffeine; Carbamates; Chronic Disease; Humans; Hypoglycemic Agents; Liver Diseases; Male; Middle Aged; Piperidines; Protein Binding

To evaluate the effect of renal impairment and renal failure on the pharmacokinetics and safety of repaglinide.. We conducted a phase I, multicenter, parallel-group, pharmacokinetic comparison trial with single and multiple doses of repaglinide in subjects with various degrees of renal impairment. Subjects with normal renal function (n = 6) and subjects with renal impairment (mild to moderate, n = 6; severe, n = 6) received treatment with 2 mg repaglinide for 7 days. Subjects in the hemodialysis group (n = 6) received two single doses of 2 mg repaglinide separated by a 7- to 14-day washout period. All subjects had repaglinide serum pharmacokinetic profiles measured for the first and last doses administered. Serum steady-state levels, urine levels, and dialysate levels were also measured.. Pharmacokinetic parameters did not show significant changes after single or multiple doses of repaglinide, although the elimination rate constant in the group with severe renal impairment decreased after 1 week of treatment. Subjects with severe impairment had significantly higher area under the curve values after single and multiple doses of repaglinide than subjects with normal renal function. No significant differences in values for maximum serum concentration or time to reach maximum concentration were detected between subjects with renal impairment and those with normal renal function. Hemodialysis did not significantly affect repaglinide clearance.. Repaglinide was safe and well tolerated in subjects with varying degrees of renal impairment. Although adjustment of starting doses of repaglinide is not necessary for renal impairment or renal failure, severe impairment may require more care when upward adjustments of dosage are made.

Topics: Adult; Analysis of Variance; Area Under Curve; Carbamates; Creatinine; Female; Gas Chromatography-Mass Spectrometry; Humans; Hypoglycemic Agents; Kidney Diseases; Male; Middle Aged; Piperidines; Protein Binding; Renal Dialysis; Severity of Illness Index

Repaglinide is a new oral hypoglycemic agent that acts as a prandial glucose regulator proposed for the treatment of type 2 diabetes by stimulating insulin secretion. The aim of this study was to explore actions of repaglinide on the rapid pulsatile insulin release by high-frequency insulin sampling and analysis of insulin-concentration time series.. We examined 8 healthy lean male subjects in a single-dose double-blind placebo-controlled crossover design. After the subjects underwent an overnight fast, blood sampling was initiated and continued every minute for 120 min. After 40 min, a single dose (0.5 mg) of repaglinide or placebo was given. Serum insulin-concentration time series were assessed by deconvolution analyses and the regularity statistic by approximate entropy (ApEn).. Average insulin concentration was increased after repaglinide administration (basal vs. stimulated period, P values are placebo vs. repaglinide) (25.1 +/- 3.6 vs. 33.5 +/- 4.1 pmol/l, P < 0.001). Insulin secretory burst mass (15.8 +/- 2.2 vs. 19.6 +/- 2.8 pmol x l(-1) x pulse(-1), P = 0.02) and amplitude (6.1 +/- 0.9 vs. 7.7 +/- 1.2 pmol x l(-1) x min(-1), P = 0.008) were augmented after repaglinide administration. A concomitant trend toward an increase in basal insulin secretion was observed (2.5 +/- 0.3 vs. 3.2 +/- 0.4 pmol x l(-1) x min(-1), p = 0.06), while the interpulse interval was unaltered (6.8 +/- 1.0 vs. 5.4 +/- 0.4 min/pulse, P = 0.38). ApEn increased significantly after repaglinide administration (0.623 +/- 0.045 vs. 0.670 +/- 0.034, P = 0.04), suggesting less orderly oscillatory patterns of insulin release.. In conclusion, a single dose of repaglinide amplifies insulin secretory burst mass (and basal secretion) with no change in burst frequency. The possible importance of these mechanisms in the treatment of type 2 diabetes characterized by disrupted pulsatile insulin secretion remains to be clarified.

Topics: Adult; Blood Glucose; C-Peptide; Carbamates; Cross-Over Studies; Double-Blind Method; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Kinetics; Male; Piperidines; Placebos

To examine the dose-related pharmacodynamics and pharmacokinetics of a single preprandial oral dose of repaglinide in patients with type 2 diabetes.. A total of 16 Caucasian men with type 2 diabetes participated in two placebo-controlled double-blind randomized cross-over studies. Patients were randomized to receive a single oral dose of repaglinide (0.5, 1.0, and 2.0 mg in study 1 and 4.0 mg in study 2) or placebo (both studies) administered 15 min before the first of two sequential identical standard meals (breakfast and lunch) that were 4 h apart. During each of the study days, which were 1 week apart, blood samples were taken at frequent intervals over a period of approximately 8 h for measurement of plasma glucose, insulin, C-peptide, and repaglinide concentrations.. During the first meal period (0-240 min), administration of repaglinide reduced significantly the area under the curve (AUC) for glucose concentration and significantly increased the AUC for insulin levels, C-peptide levels, and the insulin secretion rate. These results, compared with those of administering placebo, were dose dependent and log linear. The effect of repaglinide administration on insulin secretion was most pronounced in the early prandial period. Within 30 min, it caused a relative increase in insulin secretion of up to 150%. During the second meal period (240-480 min), there was no difference between repaglinide and placebo administration in the AUC for glucose concentration, C-peptide concentration, and the estimated insulin secretion rate.. A single dose of repaglinide (0.5-4.0 mg) before breakfast improves insulin secretion and reduces prandial hyperglycemia dose-dependently Administration of repaglinide had no effect on insulin secretion with the second meal, which was consumed 4 h after breakfast.

Topics: Administration, Oral; Area Under Curve; Blood Glucose; C-Peptide; Carbamates; Cohort Studies; Cross-Over Studies; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Administration Schedule; Eating; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Middle Aged; Piperidines

This multicenter open-label clinical trial compared the efficacy and safety of repaglinide/troglitazone combination therapy, repaglinide monotherapy, and troglitazone monotherapy in type 2 diabetes that had been inadequately controlled by sulfonylureas, acarbose, or metformin alone.. Patients with type 2 diabetes (n = 256) who had inadequate glycemic control (HbA1c > or =7.0%) during previous monotherapy were randomly assigned to receive repaglinide (0.5-4.0 mg at meals), troglitazone (200-600 mg once daily), or a combination of repaglinide (1-4 mg at meals) and troglitazone (200-600 mg once daily). After a 4-6 week washout period, the trial assessed 22 weeks of treatment: 3 weeks (weeks 0-2) of forced titration, 11 weeks of fixed-dose treatment (weeks 3-13), and 8 weeks (weeks 14-21) of titration to maximum dose. Changes in HbA1c and fasting plasma glucose (FPG) values were measured.. The combination therapy showed a significant reduction in mean HbA1c values (-1.7%) that was greater than with either type of monotherapy Repaglinide monotherapy resulted in a reduction of HbA1c values that was significantly greater than troglitazone (-0.8 vs. -0.4%) (P < 0.05). Combination therapy was more effective in reducing FPG values (-80 mg/dl) than either repaglinide (-43 mg/dl) or troglitazone (-46 mg/dl) monotherapies. Adverse events were similar in all groups.. Combination therapy with repaglinide and troglitazone leads to better glycemic control than monotherapy with either agent alone. Repaglinide monotherapy was more effective in lowering HbA1c levels than troglitazone monotherapy Repaglinide/troglitazone combination therapy was effective and did not show unexpected adverse events.

Topics: Adult; Aged; Biomarkers; Blood Glucose; Carbamates; Chromans; Cross-Over Studies; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Thiazoles; Thiazolidinediones; Troglitazone

To study the effects of rifampin (INN, rifampicin) on the pharmacokinetics and pharmacodynamics of repaglinide, a new short-acting antidiabetic drug.. In a randomized, two-phase crossover study, nine healthy volunteers were given a 5-day pretreatment with 600 mg rifampin or matched placebo once daily. On day 6 a single 0.5-mg dose of repaglinide was administered. Plasma repaglinide and blood glucose concentrations were measured up to 7 hours.. Rifampin decreased the total area under the concentration-time curve of repaglinide by 57% (P < .001) and the peak plasma repaglinide concentration by 41% (P = .001). The elimination half-life of repaglinide was shortened from 1.5 to 1.1 hours (P < .01). The blood glucose decremental area under the concentration-time curve from 0 to 3 hours was reduced from 0.94 to -0.23 mmol/L x h (P < .05), and the maximum decrease in blood glucose concentration from 1.6 to 1.0 mmol/L (P < .05) by rifampin.. Rifampin considerably decreases the plasma concentrations of repaglinide and also reduces its effects. This interaction is probably caused by induction of the CYP3A4-mediated metabolism of repaglinide. It is probable that the effects of repaglinide are decreased during treatment with rifampin or other potent inducers of CYP3A4, such as carbamazepine, phenytoin, or St John's wort.

Topics: Adult; Area Under Curve; Blood Glucose; Carbamates; Cross-Over Studies; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Drug Interactions; Enzyme Inhibitors; Female; Half-Life; Humans; Hypoglycemic Agents; Male; Mixed Function Oxygenases; Piperidines; Rifampin

Repaglinide is a newly developed oral blood glucose-lowering agent that exerts its effect by stimulating insulin secretion. This multicenter study was designed to compare the efficacy and safety of this drug with glyburide in a 1-year randomized double-blind study of outpatients with type 2 diabetes.. A total of 424 subjects (154 women, 270 men) participated and had the following characteristics: age, 61 +/- 9 years; duration of diabetes. 8 years (range 0.5-35); BMI, 28.3 +/- 3.5 kg/m2; HbA1c, 7.1 +/- 1.4%; and fasting plasma glucose, 10.8 +/- 3.1 mmol/l. The majority of the subjects (91%) were previously treated with sulfonylurea, alone or in combination with metformin. The patients were randomized to a 2:1 ratio of repaglinide (0.5-4 mg t.i.d.) or glyburide (1.75-10.5 mg daily) treatment. The study protocol included a screening visit to assess patient eligibility; a titration period of 6-8 weeks, during which the dosages of repaglinide and glyburide were optimized; and a subsequent 12-month treatment period on fixed, optimal dosages.. The trial was completed by 320 subjects, 211 (74%) in the repaglinide and 109 (78%) in the glyburide group. HbA1c initially decreased in both groups and then increased during the second half-year of the maintenance period to a similar extent in the repaglinide and glyburide subjects (0.58 and 0.45% vs. at screening, respectively). In the small group of subjects who previously controlled their condition with diet only (n = 37), a sustained improvement of metabolic control could be observed with both drugs, which was slightly better with glyburide than with repaglinide (theta HbA1c -2.4 vs. -1.0%; P < 0.05). The same trends were seen with fasting plasma glucose. There were no changes in serum lipids. Over the course of the study, 15% of the repaglinide-treated and 13% of glyburide-treated subjects withdrew due to adverse events, mostly hyperglycemia. No differences in adverse events between both drugs were reported. There were no differences in incidences of hypoglycemia.. Repaglinide is a safe and efficacious oral blood glucose-lowering agent, with a potency similar to that of glyburide. Its rapid onset of action and hepatic clearance allows meal-related administration, including in subjects with impaired kidney function.

Topics: Adult; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Double-Blind Method; Fasting; Female; Glyburide; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines

This study was designed to compare diurnal blood glucose excursions and the effects of accidental dietary noncompliance in type 2 diabetic patients who are well-controlled on either repaglinide or glyburide treatment.. This single-center double-blind randomized study comprised type 2 diabetic patients whose mean fasting blood glucose value after repaglinide/glyburide titration and stabilization was in the range of 90-140 mg/dl. The study consisted of an initial screening day, a titration period of 3 weeks, a 1-week stabilization period, a study period, and an end-of-study day. During the 3-day study period, half the patients of each group received two meals on the first day and three meals on the next 2 days, and in the other half, this sequence was reversed. Repaglinide was administered preprandially with each meal, and glyburide was administered as recommended in current labeling, i.e., either one or two daily doses before breakfast and dinner, regardless of whether lunch had been omitted. The diurnal blood glucose excursions on a day in which three meals were eaten were compared between the two groups, and the minimum blood glucose concentration (BGmin) measurements were compared between lunch and dinner on days with three and two meals.. Of the 83 randomized patients, 43 entered into the 3-day study period and completed the trial. The results showed no significant differences between the repaglinide and glyburide groups in average blood glucose excursions from fasting blood glucose (P = 0.44). The influence on the mean BGmin of omitting a meal differed significantly between the repaglinide and glyburide groups (P = 0.014). In the latter group, BGmin decreased from 77 to 61 mg/dl as a result of omitting lunch, whereas in the repaglinide group, BGmin was unchanged for the two-meal day (78 mg/dl) and the three-meal day (76 mg/dl). All hypoglycemic events (n = 6) occurred in the glyburide group on the two-meal day, in connection with omitting lunch. No hypoglycemic events were recorded in the repaglinide group.. These results suggest that treatment with repaglinide in well-controlled type 2 diabetic patients who miss or delay a meal is superior to treatment with longer-acting sulfonylurea drugs (such as glyburide) with respect to the risk of hypoglycemic episodes.

Topics: Adult; Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Diet, Diabetic; Double-Blind Method; Drug Administration Schedule; Eating; Energy Intake; Fasting; Glyburide; Humans; Hypoglycemic Agents; Middle Aged; Piperidines

To compare the effect of repaglinide in combination with metformin with monotherapy of each drug on glycemic control in patients with type 2 diabetes.. A total of 83 patients with type 2 diabetes who had inadequate glycemic control (HbA1c > 7.1%) when receiving the antidiabetic agent metformin were enrolled in this multicenter, double-blind trial. Subjects were randomized to continue with their prestudy dose of metformin (n = 27), to continue with their prestudy dose of metformin with the addition of repaglinide (n = 27), or to receive repaglinide alone (n = 29). For patients receiving repaglinide, the optimal dose was determined during a 4- to 8-week titration and continued for a 3-month maintenance period.. In subjects receiving combined therapy, HbA1c was reduced by 1.4 +/- 0.2%, from 8.3 to 6.9% (P = 0.0016) and fasting plasma glucose by 2.2 mmol/l (P = 0.0003). No significant changes were observed in subjects treated with either repaglinide or metformin monotherapy in HbA1c (0.4 and 0.3% decrease, respectively) or fasting plasma glucose (0.5 mmol/l increase and 0.3 mmol/l decrease respectively). Subjects receiving repaglinide either alone or in combination with metformin, had an increase in fasting levels of insulin between baseline and the end of the trial of 4.04 +/- 1.56 and 4.23 +/- 1.50 mU/l, respectively (P < 0.02). Gastrointestinal adverse events were common in the metformin group. An increase in body weight occurred in the repaglinide and combined therapy groups (2.4 +/- 0.5 and 3.0 +/- 0.5 kg, respectively; P < 0.05).. Combined metformin and repaglinide therapy resulted in superior glycemic control compared with repaglinide or metformin monotherapy in patients with type 2 diabetes whose glycemia had not been well controlled on metformin alone. Repaglinide monotherapy was as effective as metformin monotherapy.

Topics: Australia; Blood Glucose; C-Peptide; Carbamates; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Therapy, Combination; Fasting; Fatty Acids, Nonesterified; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Triglycerides

In this open-label, single-center, pharmacokinetic study of repaglinide, 12 healthy volunteers (6 men, 6 women) were enrolled in each of 2 groups (total, 24 volunteers). One group consisted of young adult subjects (18 to 40 years), and the other group consisted of elderly subjects (> or = 65 years). On day 1, after a 10-hour fast, all 24 subjects received a single 2-mg dose of repaglinide. Starting on day 2 and continuing for 7 days, subjects received a 2-mg dose of repaglinide 15 minutes before each of 3 meals. On day 9, subjects received a single 2-mg dose of repaglinide. Pharmacokinetic profiles, including area under the curve, maximum concentration (Cmax), time to Cmax, and half-life, were determined at completion of the single-dose and multiple-dose regimens (days 1 and 9, respectively). Trough repaglinide values were collected on days 2 through 7 to assess steady state. The single-dose and multiple-dose pharmacokinetic variables of serum repaglinide were not significantly different between young adult and elderly subjects. Repaglinide was well tolerated in both groups. Hypoglycemic events occurred in 5 young adult and 5 elderly subjects. This study demonstrates that the pharmacokinetics of repaglinide are similar in healthy young adult and elderly subjects.

Topics: Adult; Age Factors; Aged; Area Under Curve; Carbamates; Drug Administration Schedule; Female; Humans; Hypoglycemic Agents; Male; Piperidines; Single-Blind Method

This prospective, 1-year, multicenter, double-blind, randomized, parallel-group study was designed to show that repaglinide was at least equivalent to glyburide in patients with type 2 diabetes. Five hundred and seventy-six patients with type 2 diabetes of at least 6 months' duration were randomized to receive monotherapy with repaglinide (n = 383) or glyburide (n = 193). During weeks 1-8, doses were gradually increased to achieve a target fasting plasma glucose (FPG) range of 80-140 mg/dl. The final adjusted dose was maintained for 12 months. Repaglinide patients received a starting dose of 0.5 mg three times/day preprandially, adjusted as necessary to 1, 2 or 4 mg before breakfast, lunch and dinner. Glyburide patients received a starting dose of 2.5 mg before breakfast and placebo before lunch and dinner. Glyburide was increased as necessary to 5 or 10 mg before breakfast (placebo before lunch and dinner) or to 15 mg (10 mg before breakfast, placebo before lunch, and 5 mg before dinner). After study drug was stopped, patients were transferred to an appropriate therapy, as recommended by the investigator. Efficacy was assessed by changes from baseline in glycemic control parameters and in C-peptide, insulin, and lipid profiles. Repaglinide provided glycemic control that was at least as effective and potentially safer than that provided by glyburide. The glucose-lowering effect of repaglinide was most pronounced in pharmacotherapy-naive patients, who showed rapid and marked decreases in mean glycosylated hemoglobin levels from baseline (9.4%) to month 3 (7.6%) and month 12 (7.9%). Mean FPG levels also decreased overall in this group, from 222 mg/dl at baseline, to 175 mg/dl at month 3, to 188 mg/dl at month 12. At endpoint, morning C-peptide levels had increased significantly in glyburide-treated patients compared with those treated with repaglinide, but morning fasting insulin levels did not differ significantly between the two groups. Repaglinide efficacy was sustained over 1 year and was not influenced by age or sex. Overall safety and changes in lipid profile and body weight were similar with both agents, with no significant change after extended pharmacotherapy. Weight gain data for the subset of pharmacotherapy-naïve patients suggest that patients given repaglinide may gain less weight than those given glyburide. Repaglinide, at doses of 0.5-4.0 mg administered three times preprandially, was well tolerated and provided safe and consistently effectiv

Topics: Adult; Aged; Blood Glucose; C-Peptide; Carbamates; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Fibrinogen; Glyburide; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Piperidines; Prospective Studies; Triglycerides; United States; United States Food and Drug Administration

To compare the efficacy and safety of repaglinide, a novel oral prandial glucose regulator, with that of glibenclamide, an oral hypoglycaemic agent, in the treatment of patients with type 2 diabetes.. This was a 14-week, double-blind, parallel-group trail in which a total of 195 type 2 diabetic patients treated with oral hypoglycaemic agents were randomized to receive either repaglinide, administered preprandially three times daily, or glibenclamide, given preprandially once or twice daily, as per manufacturer's recommendations.. By the end of the study, the 2-h postprandial blood glucose values were lower in the repaglinide group than in the glibenclamide group, with the difference approaching statistical significance (repaglinide, 8.1 (0.6) mol x l(-1) vs glibenclamide, 9.1 (0.6)mmol x l(-1); P = 0.07). There was no statistically significant difference in the mean blood glucose level at the end of the study between the two groups (repaglinide, 7.1 (0.5) mmol x l(-1) vs glibenclamide, 7.4 (0.5) mmol x l(-1); P = 0.42), and baseline HbA1c values had decreased to the same degree in both the repaglinide [7.8% (0.1%) to 7.5% 0.1%)] and the glibenclamide groups [8.0 (0.1%) to 7.6 (0.1%)]. There are no significant differences between the repaglinide and glibenclamide treatment groups in the levels of fasting blood glucose, fructosamine, fasting C-peptide, insulin and proinsulin. Neither treatment group showed any clinically significant changes in blood lipid profiles. Repaglinide and glibenclamide were both well tolerated. No significant differences were observed between the two treatment groups with respect to adverse events, including hypoglycaemic episodes and weight change. No accumulation of repaglinide was apparent during the maintenance period.. Repaglinide is as well tolerated as glibenclamide and is equally effective in the management of type 2 diabetes. Repaglinide may, however, offer an improvement in postprandial blood glucose control compared with glibenclamide, thereby helping to reduce the relative long-term risk of diabetic complications.

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Glyburide; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Sulfonylurea Compounds

Repaglinide is a novel, rapid-acting prandial glucose regulator. To investigate the effect of repaglinide, 1 mg before each meal, in maintaining glycaemic control in Type 2 diabetic patients who either miss a meal or have an extra meal, 25 patients were randomized to either a fixed-meal regimen of three meals/day or one of two mixed-meal regimens consisting of repeating patterns of two, three or four meals/day over a 20-day period. On the 21st day each patient received three meals. Overall glycaemic control was assessed by weekly serum fructosamine concentrations and 13-point and 37-point serum glucose profiles. Mean fructosamine concentrations decreased significantly to normal values during the treatment period (from 3.10 to 2.68 mg/dl on the fixed-meal regimen and from 3.37 to 2.85 mg/dl on the mixed-meal regimens; P < 0.05), with no statistically significant difference in glucose control between the fixed-meal and mixed-meal regimen groups. Fasting serum glucose levels decreased slightly in both groups, but were not altered by the number of meals consumed. Similarly, serum glucose profiles were not altered significantly by the number of meals consumed. Repaglinide was well tolerated, and no hypoglycaemic events were reported. Serum cholesterol levels were significantly reduced (P < 0.05) in both the fixed-meal and mixed-meal groups, as were triglyceride levels in the mixed-meal group (P < 0.05). It was concluded that meal-associated treatment with repaglinide was well tolerated irrespective of the number of meals consumed/day. Thus, since missing or postponing a meal is a realistic scenario for many individuals, repaglinide offers an oral anti-diabetic treatment which can be adjusted to suit each individual's lifestyle.

Topics: Aged; Area Under Curve; Blood Glucose; Carbamates; Cholesterol; Diabetes Mellitus, Type 2; Eating; Female; Fructosamine; Humans; Hypoglycemic Agents; Indicators and Reagents; Male; Middle Aged; Nitroblue Tetrazolium; Piperidines; Prospective Studies; Triglycerides

The present study was designed to assess the disposition of (14)C-repaglinide in whole blood, plasma, urine and faeces, and to measure the total recovery of drug-related material in urine and faeces after a single 2-mg oral dose of (14)C-repaglinide during multiple dosing.. In this single-centre, open-label, phase-I trial, six healthy male volunteers received 2 mg of the prandial glucose regulator, repaglinide, four times daily for 13 days, 15 min before meals. On the morning of day 7, breakfast was omitted and the dose was given as an oral solution containing 2 mg of (14)C-repaglinide.. After oral dosing, a mean peak plasma concentration of repaglinide of 27.74 ng. ml(-1) (range: 16.84-36.65 ng. ml(-1)) was observed with a time to peak concentration of 0.5 h. Approximately 20% of repaglinide and its associated metabolites were distributed into red blood cells. No measurable (14)C-radioactivity was present in whole blood samples 6 h after dosing. Within 96 h of dosing with (14)C-repaglinide, 90% of the administered dose appeared in the faeces and 8% was excreted in urine. In the plasma, the major compound was repaglinide (61%). In the urine, the major metabolites were unidentified polar compounds, the aromatic amine (M(1)) (24%), and the dicarboxylic acid (M(2)) (22%). In the faeces, the major metabolite was M(2) (66% of administered dose). Therefore, repaglinide was excreted predominantly as metabolites and the major in vivo metabolite of repaglinide in humans was M(2). During regular dosing for 6 days, the morning plasma trough levels of repaglinide were, with very few exceptions, almost always too low to measure, indicating the absence of accumulation at this dose of 2 mg four times daily. Repaglinide was well tolerated, and there were no episodes of hypoglycaemia.. After oral dosing with repaglinide, the mean peak plasma concentration was rapidly attained and, thereafter, plasma concentrations decreased promptly. The major route of excretion was via the faeces. These properties make repaglinide a suitable insulin secretagogue for all patients with type-2 diabetes who retain sufficient beta-cell function.

Topics: Absorption; Administration, Oral; Adolescent; Adult; Area Under Curve; Carbamates; Carbon Radioisotopes; Dose-Response Relationship, Drug; Erythrocytes; Humans; Hypoglycemic Agents; Male; Metabolic Clearance Rate; Piperidines; Time Factors; Tissue Distribution

Results are presented of a double-blind, Australian multicentre study of the efficacy and safety of adjunctive repaglinide in patients with Type 2 diabetes who were controlled inadequately on metformin monotherapy. Patients had to have been on metformin for at least 6 months and to have glycated haemoglobin (HbA1c) levels of more than 7.1%. Patients were randomized to one of three treatment regimens: metformin plus placebo (MET, n = 27), repaglinide plus placebo (REP, n = 29) and metformin plus repaglinide (MET/REP, n = 27). The metformin dose remained unchanged from the prestudy dose, whereas repaglinide was titrated from 0.5 mg to 4.0 mg preprandially, depending on fasting capillary blood glucose concentration. Maintenance treatment was continued for 3 months. In the MET and REP groups, the HbA1c level decreased from 8.6% to 8.3% and from 8.6% to 8.2%, respectively; in the MET/REP group, HbA1c decreased from 8.3% to 6.9% (p < 0.001 vs. baseline; p < 0.05 vs. each monotherapy group). Overall, 59% of patients in the MET/REP group achieved a HbA1c level of less than 7.1% by the end of the study, compared with 20% and 22% in the MET and REP groups, respectively. No serious adverse events occurred that were considered to be related to study medication. Mild symptoms of hypoglycaemia were seen in the REP and MET/REP groups, in many cases during the titration phase. The combination of repaglinide with metformin was safe and well tolerated and produced a greater improvement in glycaemic control than that seen by the sum of the changes with the two agents alone.

Topics: Australia; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines

The pharmacodynamics and dose-response relationship of repaglinide, a novel oral hypoglycemic agent, were evaluated in steady-state treatment of patients with type 2 diabetes.. Efficacy of repaglinide (0.25 mg, 0.5 mg, 1 mg, 2 mg, and 4 mg) was compared to that of placebo in a double-blind, randomized, parallel-group, 4-week dose-response clinical trial in 143 patients. Repaglinide was administered 15 minutes before meals (breakfast, lunch, and dinner). Efficacy of repaglinide therapy was assessed by measuring changes from baseline in mean levels of blood glucose (BGmean), fasting serum glucose (FSG), and mean levels of serum insulin (INSmean).. Blood concentrations of repaglinide were proportional to the dose administered. INSmean values increased in all repaglinide treatment groups (by 6.7 to 12.9 microU/mL). All doses of repaglinide significantly decreased values of BGmean and FSG as compared with the placebo group. BGmean values stabilized between the second and third week of repaglinide treatment. A well-defined dose-response relationship was observed for BGmean and FSG values. All doses of repaglinide were well tolerated, and there were no serious adverse events.. These findings show that the therapeutic reduction of serum glucose levels produced by repaglinide is dose-dependent for the 0.25- to 4-mg dose range. All doses of repaglinide tested were effective and well tolerated in patients with type 2 diabetes.

Topics: Adult; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Double-Blind Method; Ethnicity; Fasting; Female; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Piperidines; Placebos; United States

The objective of the study was to assess the efficacy and safety of repaglinide compared with placebo in the treatment of patients with type 2 diabetes.. This was a phase II multicenter, double-blind, placebo-controlled, randomized, dose-adjustment and maintenance trial. After screening and a 2-week washout period, 99 patients were randomized to receive either repaglinide (n = 66) or placebo (n = 33). Patients underwent 6 weeks of dose adjustment followed by 12 weeks of dose maintenance. Fasting and stimulated glycosylated hemoglobin (HbA1c), plasma glucose, insulin, and C-peptide were measured at predetermined intervals. Adverse events and hypoglycemic episodes were recorded.. From baseline to last visit, mean HbA1c decreased from 8.5 to 7.8% in patients treated with repaglinide and increased from 8.1 to 9.3% in patients receiving placebo, with a statistically significant difference of - 1.7% (P < 0.0001) between treatment groups at the last visit. Mean fasting plasma glucose and postprandial glucose increased in patients receiving placebo and decreased in patients treated with repaglinide, with statistically significant (P < 0.01) differences between groups at the last visit. Concentrations of fasting and postprandial insulin and C-peptide were lower at the last visit compared with baseline for patients treated with placebo and higher for patients treated with repaglinide, and the differences between groups were statistically significant (P < 0.05). Overall, repaglinide was well tolerated.. This study demonstrated that repaglinide was safe and efficacious in lowering blood glucose concentrations. In addition to overall improvement in glycemic control noted with repaglinide in both sulfonylurea-treated patients and oral hypoglycemic agent-naive patients, repaglinide had a potent glucose-lowering effect in the postprandial period.

Topics: Adult; Aged; Carbamates; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines

Repaglinide is a novel prandial glucose regulator (PGR) for the treatment of type 2 diabetes. In order to investigate subject variability following oral administration of repaglinide, and to determine the relative and absolute bioavailabilities of repaglinide following oral or intravenous administration, two single-centre, open-label, randomized, crossover clinical studies were conducted.. Study 1 was conducted in 24 healthy male subjects (aged 18 to 49 years), who received repaglinide 2 mg, as either tablet or oral solution, twice each on 4 separate occasions at least 7 days apart. Study 2 was conducted in 12 healthy male subjects (aged 18 to 45 years), who received repaglinide 2 mg, either as a tablet or as an intravenous infusion over 15 minutes, once each on 2 separate occasions, with a washout period of 7-10 days.. In study 1 there was no significant difference between administration of repaglinide 2 mg, in either tablet or oral solution form with regard to intrasubject variation in AUC and Cmax. However, the intrasubject variation in t(max) and mean residence time (MRT) was significantly (p = 0.001) larger for the tablets than for the oral solution. Intersubject variation (CV) in AUC ranged from 44.7% to 62.1% after oral administration. The relative bioavailability of repaglinide (AUC(tablet)/AUC(oral solution)) was 110% (95% CI, 103%-117%). In study 2 the absolute bioavailability of repaglinide administered as a tablet was 62.5% (95% CI, 49.2%-79.5%) relative to an intravenous infusion of the same dose.. There was no evidence from either study that the tablet formulation led to greater variation in serum profiles of repaglinide. It was concluded that repaglinide is rapidly absorbed and eliminated in healthy subjects when administered orally or intravenously under fasting conditions, and that the total availability of repaglinide is similar in the tablet and oral solution formulations, though that the rate of absorption is slower for the tablet formulation.

Topics: Administration, Oral; Adolescent; Adult; Area Under Curve; Biological Availability; Carbamates; Cross-Over Studies; Diabetes Mellitus, Type 1; Humans; Hypoglycemic Agents; Infusions, Intravenous; Male; Middle Aged; Piperidines; Tablets

Two novel oral hypoglycaemic agents, NN623 and A4166, have been developed and are now in phase II clinical trial. Both agents have several common characteristics from sulphonylureas. NN623 is a stereoisomer of derivatives of benzoic acid and A4166 is also a stereoisomer of phenylalanine derivative. The predominant mechanism of the action is thought to be like sulphonylureas. Both NN623 and A4166 occupy, at least partly, a common receptor site with glibenclamide and close the ATP-dependent K+ channel. They are rapidly absorbed from the intestine and are eliminated mainly into the bile. NN623 is about 10 times more potent in hypoglycaemic action than glibenclamide and 100 times more than A4166 in terms of dosage. When 1.0 mg NN623 or 60 mg A4166 was given orally in the post-absorptive state to healthy volunteers, both agents evoked hypoglycaemia by 40 min. The duration of hypoglycaemia after NN623 was longer than after A4166 by about 1 hour. The effect of food on their bioavailability is similar. Food has marked influence on the absorption of both drugs and on their efficacy. When 1 mg of NN623 or 60 mg of A4166 was administered just before the meal, Tmax of NN623 and A4166 was 34 +/- 18 min and 18 +/- 6 min, while T1/2 was 0.64 +/- 0.12 h and 0.98 +/- 0.06 h, respectively. The postprandial rise in plasma glucose was reduced at 45 min and thereafter over 4-h after 1.0 mg NN623 and at 30 min to 90 min after 60 mg A4166. Plasma insulin levels rose more than those after placebo from 30 to 90 min after NN623 and at 20 to 40 min after A4166. Both agents stimulated insulin release much more in the postprandial than in the fasting state. There was no difference in the bioavailability after 5 or 7 days of administration. However, when administered immediately after the meal, the absorption of both drugs was delayed and the rise in plasma absorption was not suppressed until 60 min after the meal. Both fasting and postprandial hyperglycaemia were reduced after 1 to 4 weeks of premeal treatment with 0.5 mg NN623 or 60 mg A4166 in subjects with NIDDM. Plasma glucose levels were decreased over 4 h after NN623 and over 1 h after A4166. The meal-induced insulin response was almost doubled by NN623 over 2 h and 1 h by A4166. There was no difference in the bioavailability after breakfast between the first and last administrations of both drugs. In conclusion, a rapid rise in plasma insulin levels is associated with the suppression of postprandial hyperglycaemia.

Topics: Administration, Oral; Biological Availability; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glyburide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Intestinal Absorption; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Reference Values; Stereoisomerism

Insulin and glucose responses to glibenclamide were studied in comparison to a novel non-sulphonylurea drug (AG) by means of the euglycaemic clamp technique. Nine fasting male subjects were connected to a Biostator and 1.75, 3.5 or 7.0 mg glibenclamide or 1.0, 2.0 or 4.0 mg AG were given and blood glucose concentrations were clamped at 10% below basal values. Glucose infusion rates were registered over 10 h after administration of the tablet. Maximal glucose infusion rates after glibenclamide were 40% higher compared to AG (1.75 vs 1.0 mg, 3.5 vs 2.0 mg, 7.0 vs 4.0 mg, respectively) and were reached after 3-3.5 h for all doses. After glibenclamide, area under the glucose infusion curves and maximal incremental serum insulin responses were higher by 25-40% and by 30% compared to AG when low, medium and high doses of each drug were tested. However, a linear dose relationship was obtained for both drugs when the glucose infusion rate was plotted against the area under the insulin curve. In fact, both drugs were equipotent on a molecular weight basis. The hypoglycaemic index of both drugs (integrated glucose infusion rate divided by integrated insulin release) expressed per mumol of drug revealed a dose-dependent and parallel inverse curvilinear relation to increasing doses. This methodological approach allowed us to quantify and compare the metabolic effects of oral hypoglycaemic agents under standardised experimental conditions.

Topics: Administration, Oral; Adult; Blood Glucose; Carbamates; Dose-Response Relationship, Drug; Glucose; Glucose Clamp Technique; Glyburide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Piperidines; Time Factors

We have evaluated the effects of repaglinide, a new non-sulphonylurea oral hypoglycaemic agent that has a stimulatory effect on insulin secretion. Forty-four patients with NIDDM, already treated with a sulphonylurea, took part in an open, randomised, group comparison study of 12 weeks duration, during which they received either repaglinide or glibenclamide twice daily. While glibenclamide had a greater effect on fasting blood glucose (10.4 to 8.6 mmol.l-1), repaglinide significantly lowered postprandial blood glucose (13.8 to 12.2 mmol.l-1). Glycosylated haemoglobin remained unchanged in both groups, and serum fructosamine showed a tendency to fall. With both treatments total cholesterol was significantly decreased after 12 weeks, while HDL-cholesterol and triglycerides did not change. Fasting plasma insulin in the repaglinide group decreased from 80 (median value) to 67 pmol.l-1; it did not change in the glibenclamide group. Two patients in the repaglinide group did not complete the study, one for personal reasons, and one because of a rise in blood glucose. No abnormal findings attributable to repaglinide were observed in clinical and laboratory examinations, and no hypoglycaemic symptoms caused by it were observed.

Topics: Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Female; Fructosamine; Gliclazide; Glyburide; Glycated Hemoglobin; Hexosamines; Humans; Hypoglycemic Agents; Lipids; Male; Middle Aged; Piperidines; Tolbutamide

Diabetes, a common endocrine and metabolic disease in clinical practice, generally manifests a certain defect in insulin secretion due to several factors, thereafter leading to a metabolic disorder such as hyperglycemia. This study was conducted to explore the clinical effects of repaglinide combined with exercise rehabilitation on improving the blood glucose of patients with diabetes.. In this retrospective study, 100 patients with diabetes treated in our hospital from January 2018 to January 2020 were assessed for eligibility and recruited. They were assigned at a ratio of 1 : 1 to receive either repaglinide (control group) or repaglinide plus exercise rehabilitation (experimental group). Outcome measures include fasting blood glucose, 2 h postprandial blood glucose, glycosylated hemoglobin, time to normal blood glucose, blood glucose fluctuation, insulin dosage, adverse reactions, and blood glucose adequate rate.. All eligible patients showed similar pretreatment fasting blood glucose, glycosylated hemoglobin, and 2 h postprandial blood glucose (. Repaglinide plus exercise rehabilitation results in effective blood glucose control and reduced incidence of adverse reactions and yields a promising efficacy, so it is worthy of clinical promotion and application.

Topics: Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Piperidines; Retrospective Studies

Herein, the repaglinide-loaded hydrogel particles of carboxyethyl xanthan gum (CEXG) and carboxymethyl xanthan gum (CMXG) were fabricated, and controlled drug delivery performance was assessed. The XG derivatives were characterized by FTIR analyses, degree of substitution, and cytotoxicity assay. CEXG: CMXG (1:2) hydrogel particles had maximum drug entrapment efficiency of 92%. The hydrogel particles swelled a maximum of about 2.25 times in phosphate buffer (pH 6.8) than that in acidic medium (pH 1.2) in 2 h. The particles discharged 97% drug in simulated gastrointestinal pH in 4 h. The acetylation of hydrogel particles reduced the drug entrapment efficiency to 78%; however, it extended drug release up to 8 h, obeying anomalous diffusion. DSC and X-ray diffraction analyses suggested amorphous dispersion of repaglinide after entrapment. Preclinically, the acetylated hydrogels caused a maximum 52.8% reduction in blood glucose level and effectively lowered blood glucose up to 8 h. Hence, the acetylated CEXG: CMXG hydrogel particles could help control diabetes.

Topics: Blood Glucose; Carbamates; Diabetes Mellitus; Humans; Hydrogels; Piperidines; Polysaccharides, Bacterial

Endometriosis (EMS) is one of the most prevalent causes for female infertility. Herein, we investigated the effect of the repaglinide (RG), L-carnitine (LC), and bone marrow mesenchymal stem cell-conditioned medium (BMSC-CM) supplementation during in vitro maturation (IVM) on the quality, maturation, and fertilization rates, as well as embryonic quality and development of oocytes derived from normal and EMS mouse model. Immature oocytes were collected from two groups of normal and EMS-induced female NMRI mice at 6-8 weeks of age. Oocytes were cultured in IVM medium unsupplemented (control group), or supplemented with 1 M RG, 0.3 and 0.6 mg/mL LC, and 25 and 50% BMSC-CM. After 24 h of oocyte incubation, IVM rate and antioxidant status were assessed. Subsequently, the rates of fertilization, cleavage, blastulation, and embryonic development were assessed. Our results demonstrated that supplementation of IVM medium with LC and BMSC-CM, especially 50% BMSC-CM, significantly enhanced IVM and fertilization rates, and markedly improved blastocyst development and total blastocyst cell numbers in EMS-induced mice compared to the control group (53.28±0.24 vs 18.09±0.10%). Additionally, LC and BMSC-CM were able to significantly modulate EMS-induced nitro-oxidative stress by boosting total antioxidant capacity (TAC) and mitigating nitric oxide (NO) levels. Collectively, LC and BMSC-CM supplementation improved oocyte quality and IVM rates, pre-implantation developmental competence of oocytes after in vitro fertilization, and enhanced total blastocyst cell numbers probably by attenuating nitro-oxidative stress and accelerating nuclear maturation of oocytes. These outcomes may provide novel approaches to refining the IVM conditions that can advance the efficiency of assisted reproductive technologies in infertile couples.

Topics: Animals; Antioxidants; Blastocyst; Carbamates; Carnitine; Culture Media, Conditioned; Dietary Supplements; Endometriosis; Female; Fertilization in Vitro; Humans; In Vitro Oocyte Maturation Techniques; Mesenchymal Stem Cells; Mice; Oocytes; Piperidines; Pregnancy

Repaglinide (RPG) is an oral insulin secretagogue used in the treatment of diabetes. In this study, a new RPG analog was synthesized. Its antidiabetic and neuroprotective effects on dorsal root ganglions (DRG) in streptozotocin (STZ)-induced diabetic rats were examined compared to RPG. To assess the effects of 2-methoxy-4-(2-((3-methyl-1-(2-(piperidin-1-yl)phenyl)butyl)amino)-2-oxoethoxy)benzoic acid (OXR), the impact of OXR on oxidative stress biomarkers, motor function, and the expression of the glutamate dehydrogenase 1 (GLUD1), SLC2A2/glucose transporter 2 (GLUT2), and glucokinase (GCK) genes in STZ-induced diabetic rats were assessed. DRGs were examined histologically using hemotoxylin and eosin staining. Molecular docking was used to investigate the interactions between OXR and the binding site of RPG, the ATP-sensitive potassium (KATP) channel. Following 5 weeks of treatment, OXR significantly increased the level of total antioxidant power, decreased reactive oxygen species, and lipid peroxidation in the DRGs of diabetic rats. OXR restored STZ-induced pathophysiological damages in DRG tissues. Administration of OXR improved motor function of rats with diabetic neuropathy. Administration of 0.5 mg/kg OXR reduced blood glucose while promoting insulin, mainly through upregulation of messenger RNA expression of GLUD1, GLUT2, and GCK in the pancreas. Molecular docking revealed a favorable binding mode of OXR to the KATP channel. In conclusion, OXR has neuroprotective effects in diabetic rats by lowering oxidative stress, lowering blood glucose, and stimulating insulin secretion. We report that 0.5 mg/kg OXR administration was the most effective concentration of the compound in this study. OXR may be a promising target for further research on neuroprotective antidiabetic molecules.

Topics: Adenosine Triphosphate; Animals; Antioxidants; Benzoic Acid; Biomarkers; Blood Glucose; Carbamates; Diabetes Mellitus, Experimental; Eosine Yellowish-(YS); Glucokinase; Glucose Transport Proteins, Facilitative; Glutamate Dehydrogenase; Hematoxylin; Hypoglycemic Agents; Insulin; KATP Channels; Molecular Docking Simulation; Neuroprotective Agents; Oxidative Stress; Piperidines; Potassium; Rats; Reactive Oxygen Species; RNA, Messenger; Secretagogues

Serious hypoglycemia is a major adverse event associated with insulin secretagogues. Previous studies have suggested a potential relationship between angiotensin-converting enzyme inhibitors (ACEIs) used with sulfonylureas and serious hypoglycemia, and widely used drug compendia warn of this potential drug-drug interaction. We investigated the association between serious hypoglycemia and concomitant use of ACEIs in patients receiving insulin secretagogues, using the self-controlled case series design and Medicaid claims data from 5 US states linked to Medicare claims from 1999-2011. The exposure of interest was active prescription for ACEIs during insulin secretagogue or metformin (negative control object drug) episodes. The outcome was hospital presentation for serious hypoglycemia, identified by discharge diagnosis codes in inpatient and emergency department claims (positive predictive value ~ 78-89%). We calculated confounder-adjusted rate ratios (RRs) and 95% confidence internals (CIs) of outcome occurrence during ACEI-exposed vs. ACEI-unexposed time using conditional Poisson regression. The RRs for ACEIs were not statistically elevated during observation time of glipizide (RR, 1.06; CI, 0.98-1.15), glyburide (RR, 1.05; CI, 0.96-1.15), repaglinide (RR, 1.15; CI, 0.94-1.41), or metformin (RR, 1.02; CI, 0.97-1.06); but was modestly elevated with glimepiride (RR, 1.23; CI, 1.11-1.37) and modestly reduced with nateglinide (RR, 0.73; CI, 0.56-0.96). The overall pattern of results do not suggest that ACEIs used with insulin secretagogues were associated with increased rates of serious hypoglycemia, with the possible exception of glimepiride.

Topics: Administrative Claims, Healthcare; Aged; Aged, 80 and over; Angiotensin-Converting Enzyme Inhibitors; Carbamates; Databases, Factual; Diabetes Mellitus, Type 2; Drug Interactions; Female; Glipizide; Glyburide; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Male; Medicaid; Metformin; Middle Aged; Nateglinide; Pharmacoepidemiology; Piperidines; Secretagogues; Sulfonylurea Compounds; United States

Permanent neonatal diabetes mellitus (PNDM) presents with dehydration and hyperglycemia, which usually occurs during the first 12 months of life. Activating mutations of beta-cell adenosine triphosphate-sensitive potassium [KATP] channel subunits that cause opening of the channel are associated with PNDM. Some patients with PNDM respond to administration of a sulfonylurea derivative, which has long action on blood glucose even during hypoglycemia and has an apoptotic effect on beta cells. However, there have been no reports regarding treatment with meglitinide (repaglinide), which has rapid and short duration of action during the rise in blood glucose after meals that is more similar to beta cell function. It has no effects during hypoglycemia, so it does not cause neurological damage, and has no apoptotic effect on beta cells. We report herein the effects of repaglinide administration in the management and clinical outcome of two patients with PNDM during 9 and 10 years of follow-up.. Two Iranian infants were brought to our institution with poor general condition, dehydration, lethargy, and poor feeding. They had diabetic ketoacidosis at 52 days and 3.5 months of age, respectively. Their genetic analysis revealed mutations in the KCNJ11 gene encoding KIR6.2, so they both had PNDM. After treatment of diabetic ketoacidosis with insulin, they responded to sulfonylurea (glibenclamide) treatment, but were switched to repaglinide because of blood sugar fluctuations in terms of hyper- and hypoglycemia. Repaglinide was administered with the dosage of 0.04 mg/kg/day divided before every meal.. The patients were 10 and 9 years old at the last visit, with normal growth parameters. The values of self-monitored blood glucose were well-controlled, and the hemoglobin A1C (HbA1C) levels ranged from 3.6 to 6.4% during the follow-up period. There was no complication of diabetes, neurological disorder, or adverse effects related to repaglinide.. In every neonate or infant < 6 months of age with diabetes mellitus, PNDM should be considered. A trial of oral repaglinide can be performed and substituted for glibenclamide for prevention of hypoglycemia, neurological damage, and apoptosis of beta cells during long-term administration.

Topics: Benzamides; Carbamates; Diabetes Mellitus; Humans; Hypoglycemic Agents; Iran; Mutation; Piperidines

Low bioavailability of anti-diabetic drugs results in the partial absorption of the drug as they are mainly absorbed from the stomach and the lower part of the GIT. Drug bioavailability of anti-diabetic drugs can be significantly increased by prolonging gastric retention time through gastro-retentive dosage form such as floating microspheres.. The study was aimed to develop and characterize resin based floating microspheres of Repaglinide and Metformin for superior and prolonged maintenance of normoglycaemia in type-2 diabetes mellitus.. Repaglinide and metformin were complexed with amberlite resin; later resin complexed drug was encapsulated in Ethylcellulose floating microspheres. Floating microspheres were characterized for morphology, particle size, IR spectroscopy, DSC, in vitro release and buoyancy studies. Further, floating microspheres were tested for in vivo blood glucose reduction potential in Streptozocin- induced diabetic mice.. Floating microspheres had a spherical shape and slightly rough surface with the entrapment efficiency in a range of 49-78% for metformin and 52-73% for repaglinide. DSC studies revealed that no chemical interaction took place between polymer and drugs. Floating microspheres showed good buoyancy behavior (P<0.05) and prolonged drug release as compared to plain drug (P<0.05). The blood glucose lowering effect of floating microspheres on Streptozocin induced diabetic rats was significantly greater (P<0.05) and prolonged (˃12h) and normoglycaemia was maintained for 6hr.. Floating microspheres containing drug resin complex were able to prolong drug release in an efficient way for a sustained period of time; as a result, profound therapeutic response was obtained.

Topics: Animals; Carbamates; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Metformin; Mice; Microspheres; Piperidines; Rats; Resins, Synthetic

Hypoglycemia should be avoided when treating patients with diabetes. Repaglinide is an insulin secretagogue with a low hypoglycemic risk because of its rapid- and short-acting effects. However, its blood concentration has been reported to increase in combination with clopidogrel, an antiplatelet drug, and in patients with severe renal insufficiency. We herein report an elderly patient with type 2 diabetes mellitus and severe renal insufficiency who received repaglinide and hypoglycemia three days after starting clopidogrel. The concomitant use of repaglinide and clopidogrel can lead to hypoglycemia, especially in patients with severe renal insufficiency.

Topics: Aged; Blood Glucose; Carbamates; Clopidogrel; Diabetes Mellitus, Type 2; Humans; Hypoglycemia; Hypoglycemic Agents; Piperidines; Renal Insufficiency

Acanthamoeba keratitis is a sight-endangering eye infection, and causative organism Acanthamoeba presents a significant concern to public health, given escalation of contact lens wearers. Contemporary therapy is burdensome, necessitating prompt diagnosis and aggressive treatment. None of the contact lens disinfectants (local and international) can eradicate Acanthamoeba effectively. Using a range of compounds targeting cellulose, ion channels, and biochemical pathways, we employed bioassay-guided testing to determine their anti-amoebic effects. The results indicated that acarbose, indaziflam, terbuthylazine, glimepiride, inositol, vildagliptin and repaglinide showed anti-amoebic effects. Compounds showed minimal toxicity on human cells. Therefore, effects of the evaluated compounds after conjugation with nanoparticles should certainly be the subject of future studies and will likely lead to promising leads for potential applications.

Topics: Acanthamoeba castellanii; Acanthamoeba Keratitis; Acarbose; Antiprotozoal Agents; Carbamates; Cell Line; Contact Lens Solutions; Contact Lenses; HaCaT Cells; Humans; Indenes; Inositol; Nanoparticles; Piperidines; Sulfonylurea Compounds; Triazines; Vildagliptin

During diabetes human serum albumin (HSA), an important drug transport protein, can be modified by agents such as glyoxal (Go) and methylglyoxal (MGo) to form advanced glycation end-products. High-performance affinity microcolumns and zonal elution competition studies were used to compare interactions by the anti-diabetic drugs repaglinide and nateglinide with normal and Go- or MGo-modified HSA at Sudlow sites I and II of this protein. Both drugs had their strongest binding at Sudlow site II for the normal and modified forms of HSA. The association equilibrium constants at this site for repaglinide and nateglinide with normal HSA were 6.1 (± 0.2) × 10

Topics: Carbamates; Chromatography, Affinity; Glycosylation; Glyoxal; Humans; Nateglinide; Piperidines; Protein Binding; Pyruvaldehyde; Serum Albumin; Serum Albumin, Human

Accurately predicting the pharmacokinetics of compounds that are transporter substrates has been notoriously challenging using traditional in vitro systems and physiologically based pharmacokinetic (PBPK) modeling. The objective of this study was to use PBPK modeling to understand the translational accuracy of data generated with human embryonic kidney 293 (HEK293) cells overexpressing the hepatic uptake transporters organic anion transporting polypeptide (OATP) 1B1/3 with and without plasma while accounting for transporter expression. Models of four OATP substrates, two with low protein binding (pravastatin and rosuvastatin) and two with high protein binding (repaglinide and pitavastatin) were explored, and the OATP in vitro data generated in plasma incubations were used for a plasma model, and in buffer incubations for a buffer model. The pharmacokinetic parameters and concentration-time profiles of pravastatin and rosuvastatin were similar and well predicted (within 2-fold of observed values) using the plasma and buffer models without needing an empirical scaling factor, whereas the dispositions of the highly protein bound repaglinide and pitavastatin were more accurately simulated with the plasma models than the buffer models. This work suggests that data from HEK293 overexpressing transporter cells corrected for transporter expression represent a valid approach to improve bottom-up PBPK modeling for highly protein bound OATP substrates with plasma incubations and low protein binding OATP substrates with or without plasma incubations. SIGNIFICANCE STATEMENT: This work demonstrates the bottom-up approach of using in vitro data directly without employing empirical scaling factors to predict the intravenous pharmacokinetic (PK) profiles reasonably well for four organic anion transporting polypeptide (OATP) substrates. Based on these results, using HEK293 overexpressing cells, examining the impact of plasma for highly bound compounds, and incorporating transporter quantitation for the lot in which the in vitro data were generated represents a valid approach to achieve more accurate prospective PK predictions for OATP substrates.

Topics: Administration, Intravenous; Carbamates; Drug Discovery; HEK293 Cells; Humans; Liver-Specific Organic Anion Transporter 1; Models, Biological; Piperidines; Plasma; Pravastatin; Quinolines; Rosuvastatin Calcium; Solute Carrier Organic Anion Transporter Family Member 1B3

To assess the association of metformin monotherapy with the risk of all-cause deaths and cardiovascular deaths and events in type 2 diabetes patients in real clinical practice.. This retrospective, observational study comprised patients with type 2 diabetes initially treated with metformin or nonmetformin monotherapy over 2011-2016. Data were extracted from the National Healthcare Big Data database in Fuzhou, China. Propensity score matching (PSM) was performed, matching each patient on metformin to one on nonmetformin in terms of a set of covariates. The primary endpoint was all-cause death, and secondary endpoints were cardiovascular death, heart failure, and heart failure hospitalization. Covariate-adjusted associations of metformin use with all the endpoints were assessed by Cox proportional hazards models.. Among 24,099 patients, 5491 were initially treated with metformin and 18,608 with nonmetformin. PSM yielded 5482 patients in each cohort. During a median follow-up of 2.02 years, we observed 110 and 211 deaths in the metformin and nonmetformin groups, respectively. Metformin was significantly associated with reduced risk of all-cause death (adjusted hazard ratio (aHR) 0.52, 95% confidence interval (CI) 0.39-0.69), cardiovascular death (aHR 0.63, 95% CI 0.43-0.91), and heart failure (aHR 0.61, 95% CI 0.52-0.73), whereas the reduced risk in heart failure hospitalization was not statistically significant (aHR 0.70, 95% CI 0.47-1.02).. In this analysis of electronic health record data from a large database in China, metformin as first-line monotherapy greatly reduced the risk of all-cause death, cardiovascular death, and heart failure in diabetes patients as compared with nonmetformin medications.

Topics: Aged; Benzamides; Carbamates; Cardiovascular Diseases; Cause of Death; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Female; Glycoside Hydrolase Inhibitors; Heart Failure; Hospitalization; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Mortality; Nateglinide; Piperidines; Proportional Hazards Models; Retrospective Studies; Sulfonylurea Compounds; Thiazolidinediones

Repaglinide-loaded nanostructured lipid carriers (REP-NLCs) with different particle sizes were successfully designed and prepared to investigate the permeation and absorption ability by

Topics: Administration, Oral; Animals; Biological Availability; Carbamates; Drug Carriers; Drug Compounding; Intestinal Absorption; Intestinal Mucosa; Intestines; Nanostructures; Particle Size; Perfusion; Piperidines; Rats; Rats, Sprague-Dawley

This study was devised to investigate if P-glycoprotein (P-gp) mediated the drug-drug interaction (DDI) between genistein and repaglinide. When genistein was added, the plasma concentrations of repaglinide in rats were increased. The maximum plasma concentration (Cmax) of repaglinide increased from 70.80 ± 7.98 ng/mL to 124.71 ± 9.02 ng/mL and the area under the plasma concentration-time curve (AUC) increased from 134.89 ± 13.65 μg·h/L to 245.95 ± 7.24 μg·h/L. Intestinal absorption of repaglinide was markedly enhanced by genistein or P-gp inhibitor verapamil (Ver), both in situ rat jejunal perfusion studies and in vitro transport assays using everted rat intestinal sac preparations. Furthermore, the accumulation of repaglinide in both Caco-2 cells and IEC-6 cells also increased significantly in the presence of genistein and Ver. The transepithelial transport rate of repaglinide from basolateral-to-apical in MDR1-MDCK cells was 3.6-fold higher than the apical-to-basolateral rate with a net efflux ratio of 1.92 compared with mock-MDCK cells, which was significantly decreased following co-administration with genistein or Ver. In an intracellular accumulation experiment using Rhodamine 123 as a P-gp substrate, genistein significantly increased the intracellular fluorescence of Rhodamine 123. These results indicated that genistein had an inhibitory effect on the efflux function of P-gp. Through molecular docking assays we further found that genistein could bind to the nucleotide-binding domains (NBD) in the cytoplasm of P-gp, thus affecting the functions of P-gp. In conclusion, genistein inhibited the efflux of repaglinide mediated by P-gp in rats and in vitro. The findings suggested that the DDI between genistein and repaglinide is mediated by P-gp, and a dosage adjustment may be needed when they are co-administered in a clinical setting.

Topics: Animals; Area Under Curve; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Caco-2 Cells; Carbamates; Dogs; Drug Interactions; Genistein; Humans; Intestinal Absorption; Madin Darby Canine Kidney Cells; Male; Molecular Docking Simulation; Piperidines; Rats; Rats, Wistar; Rhodamine 123

Acarbose and repaglinide are two safe and effective antidiabetic agents that are especially in wide use in Asian and Middle Eastern countries. These two prandial agents share some outstanding qualities that their newer counterparts do not. While globally available in generic versions, both are oral and cheap. There is a paucity of data regarding their comparative efficacy. Herein, a head-to-head comparison of the efficacy of the two in treatment of postprandial hyperglycemia of newly-diagnosed type 2 diabetes was investigated.. One hundred and sixty-four newly-diagnosed type 2 diabetes patients with fasting plasma glucose levels of <7.2 mmol/L (130 mg/dL) but 2-hour postprandial glucose (2hPPG) levels of >10 mmol/L (180 mg/dL) were consecutively alternated between acarbose- and repaglinide-treatment for 6 months.. Per protocol analysis, 67% of acarbose-treated patients versus 85% of repaglinide-treated patients achieved 2hPPG levels of <10 mmol/L (180 mg/dL) (P = 0.05). Treatment adherence rates were 52.4% and 72%, respectively (P < 0.02). Thirteen of the repaglinide-treated and 2 of acarbose-treated patients reported at least one episode of hypoglycemia (P < 0.03). Fasting plasma glucose, 2hPPG, glycated hemoglobin and basal insulin requirement decreased more significantly with repaglinde than acarbose (P, <0.05, <0.04, <0.04 and <0.03, respectively). Weight increased with repaglinide and decreased with acarbose (P = 0.03). There were no significant changes in LDL levels with either treatment (P = 0.58), but triglycerides decreased more significantly with acarbose treatment (P = 0.03) CONCLUSIONS: Significantly higher rates of treatment-adherence and at-target glycemic levels were seen with repaglinide treatment. Weight decreased with acarbose and increased with repaglinide treatment. Hypoglycemic episodes were much less frequent with acarbose treatment.

Topics: Acarbose; Adult; Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Female; Humans; Hyperglycemia; Hypoglycemic Agents; Iran; Male; Middle Aged; Piperidines

Prediction of human pharmacokinetics is important in the preclinical stage. Values for total clearance of compounds from plasma should be one of the most important pharmacokinetic parameters for predictions. Although several physiological and empirical methods including single-species allometry for prediction of values for human clearance of compounds using humanized-liver mice have been reported, further improvement of prediction accuracies would be still expected. To optimize these approaches, we proposed methods for unbound intrinsic clearance in virtually 100% humanized-liver mouse by incorporating unbound plasma fractions of compounds in differently humanized-liver mice. Comparisons of prediction accuracies of values for human clearance of 15 model compounds were performed among our current physiological and previously reported models and single-species allometry using humanized-liver mice. Incorporation of the actual unbound plasma fractions of compounds and correction of residual mice hepatocyte in humanized-liver mice showed comparable prediction accuracy to that by single-species allometry. After exclusion of 3 compounds with large species differences in values of clearance and unbound plasma fractions between mice and humans out of 15 compounds, prediction accuracies were improved in the methods investigated. The previously and present reported physiological methods could show the good prediction accuracy of values for clearance of drugs from plasma.

Topics: Acetamides; Albuterol; Animals; Carbamates; Chromatography, Liquid; Diazepam; Diclofenac; Digitoxin; Humans; Itraconazole; Ketoprofen; Liver; Metabolic Clearance Rate; Mice; Mice, Transgenic; Naproxen; Pharmaceutical Preparations; Phenytoin; Piperidines; Pravastatin; Pyrimidines; Quinidine; Tandem Mass Spectrometry; Telmisartan; Terfenadine; Verapamil

This research study attempted to develop spray-dried solid dispersion, to enhance the solubility of repaglinide, an antidiabetic drug.. Aqueous solubility plays a major role in drug delivery because any chemical entity has to be in a dissolved state at the site of absorption, in order to get absorbed. Solid dispersion (SD) is one of the widely used techniques to enhance solubility and hence dissolution rate of poorly soluble drugs.. Repagnilide, in hypromellose acetate succinate. Spray dried solid dispersion comprising (w/w) drug:polymer ratio of 1:3.82, 2.56% of aerosil and inlet temperature of 90 °C, corresponded to the best formulation obtained in this work. It showed. Thus, it can be concluded that spray-dried solid dispersion prepared using HPMCAS is a useful technique for solubility and dissolution enhancement of repaglinide.

Topics: Acetates; Animals; Carbamates; Chemistry, Pharmaceutical; Hypromellose Derivatives; Pharmaceutical Preparations; Piperidines; Rats; Solubility; Succinates

Niosomes, bilayer vesicles formed by the self-assembly of nonionic surfactants, are receiving increasing attention as potential oral drug delivery systems but the impact of niosomal formulation parameters on their oral capability has not been studied systematically. The aim of this study was to investigate the impact of surfactant composition and surface charge of niosomes in enhancing oral bioavailability of repaglinide (REG) as a BCS II model drug.. Niosomes (13 formulations) from various nonionic surfactants having HLB in the range of 4-28 (Tweens, Spans, Brijs, Myrj, poloxamer 188, TPGS and Labrasol) were prepared and characterized concerning their loading efficiency, hydrodynamic diameter, zeta potential, drug release profile, and stability. The oral pharmacokinetics of the selected formulations were studied in rats (8 in vivo groups).. The results revealed that type of surfactant markedly affected the in vitro and in vivo potentials of niosomes. The C. Cationic Tween 80-based niosomes may represent a promising platform to develop oral delivery systems for BCS II drugs.

Topics: Administration, Oral; Animals; Biological Availability; Caco-2 Cells; Carbamates; Drug Delivery Systems; Drug Liberation; Hexoses; Humans; Liposomes; Male; Piperidines; Polysorbates; Rats, Wistar; Surface-Active Agents

The aim of the present study was to develop modified nanoemulsions to improve the oral bioavailability and pharmacokinetics of a poor water-soluble drug, repaglinide (RPG). The repaglinide-loaded nanoemulsions (RPG-NEs) were prepared from olive oil as internal phase, span 80, tween 80, and poloxamer 188 as emulsifiers, using homogenization technique. The mean droplet size, zeta potential, and entrapment efficiency of RPG-NEs were 86.5 ± 3.4 nm, -33.8 ± 2.1 mV, and 96.3 ± 2.3%, respectively. The chitosan-coated RPG-NEs (Cs-RPG-NEs) showed an average droplet size of 149.3 ± 3.9 nm and a positive zeta-potential of +31.5 ± 2.8 mV. Drug release profile of RPG-NEs was significantly higher than free drug in the simulated gastrointestinal fluids (p < .005). The in vivo study revealed 3.51- and 1.78-fold increase in the AUC

Topics: Administration, Oral; Animals; Biological Availability; Carbamates; Chitosan; Drug Compounding; Drug Liberation; Emulsions; Gastrointestinal Absorption; Humans; Hypoglycemic Agents; Intracellular Fluid; Male; Nanocapsules; Piperidines; Poloxamer; Polysorbates; Rats, Sprague-Dawley; Solubility

As rifampicin can cause the induction and inhibition of multiple metabolizing enzymes and transporters, it has been challenging to accurately predict the complex drug-drug interactions (DDIs). We previously constructed a physiologically-based pharmacokinetic (PBPK) model of rifampicin accounting for the components for the induction of cytochrome P450 (CYP) 3A/CYP2C9 and the inhibition of organic anion transporting polypeptide 1B (OATP1B). This study aimed to expand and verify the PBPK model for rifampicin by incorporating additional components for the induction of OATP1B and CYP2C8 and the inhibition of multidrug resistance protein 2. The established PBPK model was capable of accurately predicting complex rifampicin-induced alterations in the profiles of glibenclamide, repaglinide, and coproporphyrin I (an endogenous biomarker of OATP1B activities) with various dosing regimens. Our comprehensive rifampicin PBPK model may enable quantitative prediction of DDIs across diverse potential victim drugs and endogenous biomarkers handled by multiple metabolizing enzymes and transporters.

Topics: Biomarkers; Carbamates; Computer Simulation; Coproporphyrins; Drug Interactions; Glyburide; Humans; Models, Biological; Organic Anion Transporters; Piperidines; Rifampin

Topics: Administration, Oral; Animals; Blood Glucose; Calorimetry, Differential Scanning; Carbamates; Drug Carriers; Drug Compounding; Drug Evaluation, Preclinical; Drug Liberation; Glucose Tolerance Test; Hydrophobic and Hydrophilic Interactions; Hypoglycemic Agents; Models, Animal; Nanofibers; Piperidines; Polyvinyl Alcohol; Povidone; Rats; Solubility; Surface Properties

Firstly, metformin and repaglinide were degraded under high temperature/humidity, UV/VIS light, in different pH and oxidative conditions. Secondly, a new validated LC-UV method was examined, as to whether it validly determined these drugs in the presence of their degradation products and whether it is suitable for estimating degradation kinetics. Finally, the respective LC-MS method was used to identify the degradation products. In addition, using FT-IR method, the stability of metformin and repaglinide was scrutinized in the presence of polyvinylpyrrolidone (PVP), mannitol, magnesium stearate, and lactose. Significant degradation of metformin, following the first order kinetics, was observed in alkaline medium. In the case of repaglinide, the most significant and quickest degradation, following the first order kinetics, was observed in acidic and oxidative media (0.1 M HCl and 3% H

Topics: Administration, Oral; Carbamates; Chromatography, Liquid; Drug Stability; Excipients; Hypoglycemic Agents; Kinetics; Mass Spectrometry; Metformin; Piperidines; Reproducibility of Results; Solutions; Spectroscopy, Fourier Transform Infrared; Ultraviolet Rays

The transcription factor FOXO3 is associated with poor outcome in high-stage neuroblastoma (NB), as it facilitates chemoprotection and tumor angiogenesis. In other tumor entities, FOXO3 stimulates metastasis formation, one of the biggest challenges in the treatment of aggressive NB. However, the impact of FOXO3 on the metastatic potential of neuronal tumor cells remains largely unknown. In the present study, we uncover the small leucine-rich proteoglycan family member lumican (LUM) as a FOXO3-regulated gene that stimulates cellular migration in NB. By a drug-library screen we identified the small molecular weight compound repaglinide (RPG) as a putative FOXO3 inhibitor. Here, we verify that RPG binds to the FOXO3-DNA-binding-domain (DBD) and thereby silences the transcriptional activity of FOXO3. Consistent with the concept that the FOXO3/LUM axis enhances the migratory capacity of aggressive NB cells, we demonstrate that stable knockdown of LUM abrogates the FOXO3-mediated increase in cellular migration. Importantly, FOXO3 inhibition by RPG represses the binding of FOXO3 to the LUM promoter, inhibits FOXO3-mediated LUM RNA and protein expression, and efficiently abrogates FOXO3-triggered cellular "wound healing" as well as spheroid-based 3D-migration. Thus, silencing the FOXO3/LUM axis by the FDA-approved compound RPG represents a promising strategy for novel therapeutic interventions in NB and other FOXO3-dependent tumors.

Topics: Carbamates; Cell Line, Tumor; Cell Movement; Down-Regulation; Forkhead Box Protein O3; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Lumican; Neuroblastoma; Piperidines; Promoter Regions, Genetic; Protein Binding

1. The objective of our study was to develop and validate a cocktail approach to allow the simultaneous characterization of various CYP450-mediated oxidations by human heart microsomes for nine probe drug substrates, namely, 7-ethoxyresorufin, bupropion, repaglinide, tolbutamide, bufuralol, chlorzoxazone, ebastine, midazolam and dodecanoic acid. 2. The first validation step was conducted using recombinant human CYP450 isoenzymes by comparing activity measured for each probe drug as a function of (1) buffer used, (2) selectivity towards specific isoenzymes and (3) drug interactions between probes. Activity was all measured by validated LC-MSMS methods. 3. Two cocktails were then constituted with seven of the nine drugs and subjected to kinetic validation. Finally, all probe drugs were incubated with human heart microsomes prepared from ventricular tissues obtained from 12 patients undergoing cardiac transplantation. 4. Validated cocktail #1 including bupropion, chlorzoxazone, ebastine and midazolam was used to characterize CYP2B6-, 2E1-, 2J2- and 3A5-mediated metabolism in human hearts. 5. Cocktail #2 which includes bufuralol, 7-ethoxyresorufin and repaglinide failed the validation step. Substrates in cocktail #2 as well as tolbutamide and dodecanoic acid had to be incubated separately because of their physico-chemical characteristics (solubility and ionization) or drug interactions. 6. Activity in HHM was the highest towards ebastine, chlorzoxazone and tolbutamide.

Topics: Bupropion; Butyrophenones; Carbamates; Chlorzoxazone; Cytochrome P-450 Enzyme System; Drug Evaluation, Preclinical; Ethanolamines; Humans; Lauric Acids; Microsomes; Midazolam; Myocardium; Oxazines; Piperidines; Tolbutamide

Lifestyle diseases such as diabetes and arteriosclerosis are rising in the increasingly aging society, and the number of patients with daily intake of glucose-lowering medication has also increased. Interestingly, knowledge about oral antidiabetics with regard to wound healing is scarce. Therefore, the aim of this study was to identify possible (side) effects of the most frequently prescribed oral antidiabetics on skin cells and wound healing. Four oral antidiabetics of different substance classes (i.e., metformin, glibenclamide, sitagliptin, repaglinide) were investigated with regard to the promotion of cell metabolism and migration of human skin fibroblasts and keratinocytes by XTT and scratch assays. In addition, histological and immunohistochemical analyses were performed in a 3D wound model to address the impact of the antidiabetics on regeneration processes, such as cell migration, fibroblast activity, epidermal thickness, and cell apoptosis. In comparison to systemic application, metformin displayed the most adverse effects in vitro in nearly all analyses, interestingly at serum equivalent concentrations. In contrast, sitagliptin and glibenclamide had a slight but insignificant effect on fibroblasts compared with keratinocytes. Repaglinide tended to have a negative influence on keratinocyte metabolism. Interestingly, antidiabetics generally induced a significantly enhanced rate of apoptosis in fibroblasts, with the exception of repaglinide.Antidiabetics influenced key players in wound healing, namely, keratinocytes and fibroblasts. Particularly, metformin impaired human skin cells. These findings should be kept in mind in further studies because of their putative relevance in patients suffering from chronic wounds that do not respond to various wound therapies.

Topics: Administration, Oral; Apoptosis; Carbamates; Caspases; Cell Line; Endopeptidases; Fibroblasts; Gelatinases; Glyburide; Humans; Hypoglycemic Agents; Keratinocytes; Membrane Proteins; Metformin; Piperidines; Receptors, CXCR4; Serine Endopeptidases; Sitagliptin Phosphate; Wound Healing

Physiologically based pharmacokinetic (PBPK) models often include several sets of correlated parameters, such as organ volumes and blood flows. Because of recent advances in proteomics, it has been demonstrated that correlations are also present between abundances of drug-metabolising enzymes in the liver. As the focus of population PBPK has shifted the emphasis from the average individual to theoretically conceivable extremes, reliable estimation of the extreme cases has become paramount. We performed a simulation study to assess the impact of the correlation between the abundances of two enzymes on the pharmacokinetics of drugs that are substrate of both, under assumptions of presence or lack of such correlations. We considered three semi-physiological models representing the cases of: (1) intravenously administered drugs metabolised by two enzymes expressed in the liver; (2) orally administered drugs metabolised by CYP3A4 expressed in the liver and gut wall; (3) intravenously administered drugs that are substrates of CYP3A4 and OATP1B1 in the liver. Finally, the impact of considering or ignoring correlation between enzymatic abundances on global sensitivity analysis (GSA) was investigated using variance based GSA on a reduced PBPK model for repaglinide, substrate of CYP3A4 and CYP2C8. Implementing such correlations can increase the confidence interval for population pharmacokinetic parameters (e.g., AUC, bioavailability) and impact the GSA results. Ignoring these correlations could lead to the generation of implausible parameters combinations and to an incorrect estimation of pharmacokinetic related parameters. Thus, known correlations should always be considered in building population PBPK models.

Topics: Biological Availability; Carbamates; Computer Simulation; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Humans; Inactivation, Metabolic; Liver; Liver-Specific Organic Anion Transporter 1; Models, Biological; Pharmaceutical Preparations; Pharmacokinetics; Piperidines

Topics: Acanthamoeba castellanii; Amebicides; Anti-Infective Agents; Carbamates; HeLa Cells; Humans; Hypoglycemic Agents; Metal Nanoparticles; Nanoconjugates; Piperidines; Silver; Sulfonylurea Compounds; Vildagliptin

Repaglinide (RPG) is a short-acting insulin secretagogue widely prescribed for the treatment of type 2 diabetes. It boosts insulin secretion by inhibiting the pancreatic ATP-sensitive potassium channel (K

Topics: Adenosine Triphosphate; Amino Acid Motifs; Amino Acid Sequence; Animals; Binding Sites; Carbamates; HEK293 Cells; Humans; Mice; Models, Molecular; Pancreas; Piperidines; Potassium Channels, Inwardly Rectifying; Protein Binding; Protein Interaction Mapping; Protein Subunits; Sulfonylurea Receptors

Several insulin secretagogues are widely used to treat diabetes; however, few outcome-based comparative studies have clarified which one of these should be used when indicated. We investigated mortality and cardiovascular event risk associated with optimal forms of insulin secretagogues.. In this cohort study using real-world data from the diabetes database of Taiwan's National Health Insurance program, patients with diabetes were enrolled if their initial treatment was glimepiride, gliclazide, glipizide, glyburide, or repaglinide from 1999 to 2013. Each group was propensity score-matched to the glimepiride group before comparison. Primary outcomes were all-cause mortality and the combined cardiovascular event risk of acute myocardial infarction and ischemic stroke. Hazard ratios were calculated by Cox proportional hazard regression models.. There were 66,790, 97,426, 38,806, 92,970, and 11,468 participants in the glimepiride, gliclazide, glipizide, glyburide, and repaglinide groups, respectively. The median follow-up time was 8 years. Glimepiride was associated with the best clinical outcome, showing the lowest mortality and lowest cardiovascular event risk of the five insulin secretagogues. Using patients on glimepiride as the reference group, the adjusted hazard ratios of all-cause mortality and cardiovascular event risk were 1.52 (p < 0.001) and 1.22 (p = 0.005) for gliclazide, 1.42 (p < 0.001) and 1.19 (p = 0.073) for glipizide, 1.43 (p < 0.001) and 1.32 (p < 0.001) for glyburide, and 1.88 (p < 0.001) and 1.69 (p = 0.001) for repaglinide.. For patients with diabetes taking an insulin secretagogue, glimepiride was associated with the best clinical outcome, showing the lowest mortality and cardiovascular event risk.

Topics: Aged; Carbamates; Cardiovascular Diseases; Cohort Studies; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Female; Follow-Up Studies; Gliclazide; Glipizide; Glyburide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Middle Aged; Mortality; Piperidines; Secretagogues; Sulfonylurea Compounds; Taiwan

Objective Previous studies have suggested that variations in the ABCC8 gene may be closely associated with T2DM susceptibility and repaglinide response. However, these results have not been entirely consistent, and there are no related studies in a Chinese population, suggesting the need for further exploration. The current study investigated the associations of the ABCC8 rs1801261 polymorphism with type 2 diabetes mellitus (T2DM) susceptibility and repaglinide therapeutic efficacy in Chinese Han T2DM patients. Methods A total of 234 T2DM patients and 105 healthy subjects were genotyped for ABCC8 rs1801261 polymorphism by a polymerase chain reaction-restriction fragment length polymorphism assay. A total of 70 patients with the same genotypes of CYP2C8*3 139Arg and OATP1B1 521TT were randomized to orally take 3 mg repaglinide per day (1 mg each time before meals) for 8 consecutive weeks. The pharmacodynamic parameters of repaglinide and biochemical indicators were then determined before and after repaglinide treatment. Results The frequency of ABCC8 rs1801261 allele was higher in T2DM patients than in the control subjects (22.6% vs.11.0%, p<0.01). After repaglinide treatment, T2DM patients carrying genotype CT showed a significantly attenuated efficacy on FPG (p<0.01) and HbA1c (p<0.01) compared with those with genotype CC. Conclusion These results suggested that the ABCC8 rs1801261 polymorphism might influence T2DM susceptibility and the therapeutic effect of repaglinide in Chinese Han T2DM patients. This study was registered in the Chinese Clinical Trial Register on May 14, 2013 (No. ChiCTR-CCC13003536).

Topics: Alleles; Asian People; Carbamates; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Genotype; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Polymerase Chain Reaction; Polymorphism, Genetic; Polymorphism, Restriction Fragment Length; Sulfonylurea Receptors

This nested case-control study evaluated the potential interaction between repaglinide and clopidogrel. Cases were defined by inpatient admissions or emergency department visits due to hypoglycemia. Concomitant use of repaglinide and clopidogrel within 3 days before the hypoglycemic event was the exposure of interest. For each case, up to four controls were randomly selected and matched by age, sex, type of glinide used (repaglinide or nateglinide), and time since cohort entry to the index date. Hypoglycemic risk was estimated by conditional logistic regressions. Concomitant use of repaglinide and clopidogrel was associated with an increased risk of hypoglycemia compared with repaglinide alone (adjusted odds ratio: 2.42; 95% confidence interval: 1.75-3.35). No significant associations were found with the two negative control object drug concomitants: nateglinide and clopidogrel and repaglinide and aspirin (without clopidogrel use). Our study suggests drug interaction between clopidogrel and repaglinide is clinically relevant and could increase the risk for hypoglycemia.

Topics: Aged; Aspirin; Carbamates; Case-Control Studies; Clopidogrel; Drug Interactions; Female; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Piperidines; Platelet Aggregation Inhibitors

ATP-sensitive potassium (K

Topics: Animals; Binding Sites; Carbamates; Cell Line; Cricetinae; Cryoelectron Microscopy; Cysteine; Glyburide; Humans; KATP Channels; Mammals; Models, Molecular; Mutation; Pharmaceutical Preparations; Piperidines; Potassium Channels, Inwardly Rectifying; Protein Binding; Rats

Seven unknown impurities in Repaglinide bulk drug batches at below 0.1% (ranging from 0.05 to 0.10%) were detected by an ultra-performance liquid chromatographic (UPLC) method. These impurities were isolated from the crude sample of Repaglinide using preparative high performance liquid chromatography (prep-HPLC). Based on liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI/MS) study, the chemical structures of seven new impurities (8, 9, 10, 11, 13, 14, and 16) were presumed and characterized as 4-(cyanomethyl)-2-ethoxybenzoic acid (8), 4-(cyanomethyl)-2-ethoxy-N-(3-methyl-1-(2-(piperidin-1-yl)phenyl)butyl)benzamide (9), 4-(2-amino-2-oxoethyl)-2-ethoxy-N-(3-methyl-1-(2-(piperidin-1-yl)phenyl)butyl) benzamide (10) and 2-(3-ethoxy-4-((3-methyl-1-(2-(piperidin-1-yl)phenyl)butyl) carbamoyl) phenyl) acetic acid (11) and 4-(cyanomethyl)-N-cyclohexyl-2-ethoxybenzamide (13), 2-(4-(cyclohexylcarbamoyl)-3-ethoxyphenyl) acetic acid (14) and N-cyclohexyl-4-(2-(cyclohexylamino)-2-oxoethyl)-2-ethoxybenzamide (16). The complete spectral analysis, proton nuclear magnetic resonance (

Topics: Carbamates; Chromatography, High Pressure Liquid; Chromatography, Liquid; Drug Contamination; Hypoglycemic Agents; Piperidines; Spectrometry, Mass, Electrospray Ionization; Spectroscopy, Fourier Transform Infrared; Tandem Mass Spectrometry

Ethnic variability in the pharmacokinetics of organic anion transporting polypeptide (OATP) 1B1 substrates has been observed, but its basis is unclear. A previous study hypothesizes that, without applying an intrinsic ethnic variability in transporter activity, allele frequencies of transporters cannot explain observed ethnic variability in pharmacokinetics. However, this hypothesis contradicts the data collected from compounds that are OATP1B1 substrates but not breast cancer resistance protein (BCRP) substrates.. The objective of this study is to evaluate a hypothesis that is physiologically reasonable and more consistent with clinical observations.. We evaluated if allele frequencies of two transporters (OATP1B1 and BCRP) are key contributors to ethnic variability. In this hypothesis, the same genotype leads to the same activity independent of ethnicity, in contrast to the previous hypothesis of intrinsic ethnic variability in OATP1B1 activity. As a validation, we perform mechanistic pharmacokinetic modeling for SLCO1B1 (encoding OATP1B1) and ABCG2 (encoding BCRP) genotyped pharmacokinetic data from 18 clinical studies with healthy Caucasian and/or Asian subjects.. Simulations based on the current hypothesis reasonably describe SLCO1B1 and ABCG2 genotyped pharmacokinetic time course data for five transporter substrates (atorvastatin, pitavastatin, pravastatin, repaglinide, and rosuvastatin) in Caucasian and Asian populations.. This hypothesis covers the observations that can (e.g., ethnic differences in rosuvastatin pharmacokinetics) or cannot (e.g., lack of differences for pitavastatin pharmacokinetics) be explained by the previous hypothesis. It helps to characterize sources of ethnic variability and provides a foundation for predicting ethnic variability in transporter substrate pharmacokinetics.

Topics: Asian People; Atorvastatin; ATP Binding Cassette Transporter, Subfamily G, Member 2; Carbamates; Computer Simulation; Gene Frequency; Genotype; Healthy Volunteers; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Models, Biological; Neoplasm Proteins; Pharmacogenomic Variants; Phenotype; Piperidines; Pravastatin; Quinolines; Rosuvastatin Calcium; White People

One adverse effect of methylprednisolone (MP) pulse therapy is an acute dose-dependent increase in the blood glucose level. Five patients with thyroid ophthalmopathy but normal glucose tolerance received MP pulse therapy (3 cycles, 3 days/week) and were assessed by continuous glucose monitoring. Steroid therapy increased the mean sensor glucose level, and all patients developed steroid-induced diabetes. The patients were treated alternately with mitiglinide (30 mg/day) and repaglinide (1.5 mg/day) during the second or third MP pulse therapy. The sensor glucose levels before lunch and dinner were more favorable during treatment with repaglinide than during treatment with mitiglinide. Repaglinide may be more clinically appropriate than mitiglinide.

Topics: Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Female; Graves Ophthalmopathy; Humans; Hyperglycemia; Hypoglycemic Agents; Isoindoles; Male; Methylprednisolone; Middle Aged; Piperidines; Treatment Outcome

Topics: Antitubercular Agents; Area Under Curve; Carbamates; Clofazimine; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Desipramine; Drug Interactions; Humans; Midazolam; Models, Biological; Piperidines; Tuberculosis, Multidrug-Resistant

The aim of the present work was to study the use of cellulose nanocrystals (CNC) and chitosan nanoparticles (CHNP) for developing controlled-release drug delivery system of the anti-hyperglycemic drug Repaglinide (RPG). CNC was isolated from palm fruit stalks by sulfuric acid hydrolysis; the dimensions of the isolated nanocrystals were 86-237 nm in length and 5-7 nm in width. Simple and economic method was used for the fabrication of controlled release drug delivery system from CNC and CHNP loaded with RPG drug via ionic gelation of chitosan in the presence of CNC and RPG. The prepared systems showed high drug encapsulation efficiency of about ~98%. Chemical modification of CNC by oxidation to introduce carboxylic groups on their surface (OXCNC) was also carried out for further controlling of RPG release. Particles size analysis showed that the average size of CHNP was about 197 nm while CHNP/CNC/RPG or CHNP/OXCNC/RPG nanoparticles showed average size of 215-310 nm. Compatibility studies by Fourier transform infrared (FTIR) spectroscopy showed no chemical reaction between RPG and the system's components used. By studying the drug release kinetic, all the prepared RPG formulations followed Higuchi model, indicating that the drug released by diffusion through the nanoparticles polymeric matrix.

Topics: Carbamates; Cellulose; Chitosan; Delayed-Action Preparations; Drug Carriers; Drug Delivery Systems; Drug Liberation; Humans; Hydrolysis; Hyperglycemia; Nanocomposites; Nanoparticles; Piperidines; Spectroscopy, Fourier Transform Infrared

Statistically significant positive correlations are reported for the abundance of hepatic drug-metabolizing enzymes. We investigate, as an example, the impact of CYP3A4-CYP2C8 intercorrelation on the predicted interindividual variabilities of clearance and drug-drug interactions (DDIs) for repaglinide using physiologically based pharmacokinetic (PBPK) modelling.. PBPK modelling and simulation were employed using Simcyp Simulator (v15.1). Virtual populations were generated assuming intercorrelations between hepatic CYP3A4-CYP2C8 abundances derived from observed values in 24 human livers. A repaglinide PBPK model was used to predict PK parameters in the presence and absence of gemfibrozil in virtual populations, and the results were compared with a clinical DDI study.. Coefficient of variation (CV) of oral clearance was 52.5% in the absence of intercorrelation between CYP3A4-CYP2C8 abundances, which increased to 54.2% when incorporating intercorrelation. In contrast, CV for predicted DDI (as measured by AUC ratio before and after inhibition) was reduced from 46.0% in the absence of intercorrelation between enzymes to 43.8% when incorporating intercorrelation: these CVs were associated with 5th/95th percentiles (2.48-11.29 vs. 2.49-9.69). The range of predicted DDI was larger in the absence of intercorrelation (1.55-77.06) than when incorporating intercorrelation (1.79-25.15), which was closer to clinical observations (2.6-12).. The present study demonstrates via a systematic investigation that population-based PBPK modelling incorporating intercorrelation led to more consistent estimation of extreme values than those observed in interindividual variabilities of clearance and DDI. As the intercorrelations more realistically reflect enzyme abundances, virtual population studies involving PBPK and DDI should avoid using Monte Carlo assignment of enzyme abundance.

Topics: Adult; Carbamates; Clinical Trials as Topic; Computer Simulation; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP2C8 Inhibitors; Cytochrome P-450 CYP3A; Drug Interactions; Female; Gemfibrozil; Humans; Hypoglycemic Agents; Male; Microsomes, Liver; Models, Biological; Piperidines; Young Adult

Topics: Activating Transcription Factor 6; Animals; Carbamates; Cognition Disorders; Disease Models, Animal; Hippocampus; Humans; Huntington Disease; Kv Channel-Interacting Proteins; Memory Disorders; Mice, Inbred C57BL; Mice, Transgenic; Neuronal Calcium-Sensor Proteins; Neurons; Piperidines; Rotarod Performance Test

The dynamics of insulin secretion stimulated by repaglinide, a glinide, and the combinatorial effects of repaglinide and incretin were investigated. At 4.4 mM glucose, repaglinide induced insulin secretion with a gradually increasing first phase, showing different dynamics from that induced by glimepiride, a sulfonylurea. In the presence of glucagon-like peptide-1 (GLP-1), insulin secretion by repaglinide was augmented significantly but to lesser extent and showed different dynamics from that by glimepiride. At 4.4 mM glucose, the intracellular Ca

Topics: Animals; Calcium; Carbamates; Drug Interactions; Exocytosis; Glucagon-Like Peptide 1; Guanine Nucleotide Exchange Factors; Insulin; Insulin Secretion; Insulin-Secreting Cells; Intracellular Space; Mice; Mice, Inbred C57BL; Piperidines

Stress stability studies of drugs have been recognized as an essential part of the drug development process. These studies are used to investigate the intrinsic stability of the drugs and for the development of a selective stability indicating assay method (SIAM). Stress testing is also useful for the formulation and packaging development, shelf-life determination and designing of manufacturing processes. As per regulatory guidelines, stress degradation studies and structural characterization should be carried out to establish degradation pathways of the drug, which is essential from both the efficacy and safety point of view. As the stress stability studies of repaglinide have not been reported in the literature, the present study has been undertaken.. The forced degradation of RP carried out as per ICH guidelines results in the formation of six degradation products which have been characterized using LC/MS/MS in combination with accurate mass measurements.

Topics: Carbamates; Chromatography, High Pressure Liquid; Drug Stability; Hydrolysis; Oxidation-Reduction; Piperidines; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

On account of the potential inhibition of OATP1B1 (organic anion transporting polypeptide) by angiotensin II receptor blockers (ARBs) and the effects of SLCO1B1 (solute carrier organic anion transporter family member) polymorphism, the aim of current study is to assess the impact of ARBs on the pharmacokinetics (PK) and pharmacodynamics (PD) of repaglinide in Chinese healthy volunteers with different SLCO1B1 genotypes.. The in vitro study was conducted on irbesartan, valsartan, olmesartan, and losartan by using HEK293 cells transfected with OATP1B1. Data on drug interactions between repaglinide and irbesartan from 21 healthy Chinese-Han male volunteers were collected and analyzed.. IC. SLCO1B1 c.521 T>C polymorphism affects the PK of repaglinide in Chinese population. Irbesartan increased repaglinide exposure in subjects with SLCO1B1 c.521 TT genotype, but not SLCO1B1 c.521 TC genotype.

Topics: Adult; Asian People; Biphenyl Compounds; Blood Glucose; Carbamates; Cells, Cultured; China; Dose-Response Relationship, Drug; Drug Interactions; Genotype; Healthy Volunteers; Humans; Imidazoles; Irbesartan; Liver-Specific Organic Anion Transporter 1; Losartan; Male; Piperidines; Polymorphism, Single Nucleotide; Tetrazoles; Valsartan; Young Adult

The objective of the study was to improve the bioavailability of poorly soluble repaglinide (RPG) by preparing nanosuspension with poloxamer 188 using high pressure homogenization (HPH). The recent patents on nanocrystals (US20150337006A1) facilitated selection of drug and polymer.. Suspensions containing dissimilar sized particles were prepared by ultrasonication and HPH. The prepared aqueous suspensions were lyophilized and then characterized. Further, the dried aqueous suspensions were evaluated for drug content, solubility, in vitro dissolution, oral bioavailability study and stability study.. RPG nanoparticles size, polydispersity index (PDI) and zeta potential were found to be 280.8 ± 15 nm, 0.279 ± 0.04 and - 25.81 ± 1.6mV, respectively. DSC and XRD results showed that RPG particles in aqueous suspensions were present in a crystalline state; however, RPG nanoparticles exhibited decreased lattice energy due to smaller particle size. Nanoparticles prepared by HPH exhibited significant improvements in solubility and dissolution rate. Oral bioavailability was found to be enhanced by 1.93 fold in comparison with that of plain RPG. The nanosuspension was found to be stable when stored at 5°C ± 3°C.. The outcomes of the study revealed significant enhancement in dissolution rate and oral bioavailability of RPG due to size reduction to nano range by HPH.

Topics: Administration, Oral; Animals; Biological Availability; Carbamates; Drug Liberation; Drug Stability; Nanoparticles; Particle Size; Patents as Topic; Piperidines; Poloxamer; Rabbits; Solubility; Surface Properties; Suspensions

Repaglinide (RG) is a prandial glucose regulator used for the treatment of type 2 diabetes. Our recent study showed \ that RG plays an important role in cyclosporine A (CsA)-induced nephrotoxicity through its antioxidant properties. However, it is \ not known whether or not RG has any protective effect on CsA-induced renal tubular toxicity by affecting\ apoptosis and expression of \ apoptosis-associated protein. The purpose of this study was to investigate the effects of RG on CsA-induced renal tubule apoptosis and\ Bax\ and \ Bcl-2\ protein expression in rats.. Forty male Sprague Dawley rats weighing 250–300 g were randomly divided into four groups: administrations \ of olive oil (control, per os (PO)), CsA (30 mg/kg in olive oil, subcutaneous (SC)), and RG (0.2 or 0.4 mg/kg, PO) plus CsA (30 mg/kg \ in olive oil, SC) every day for 15 days.. Our results showed that SC administration of CsA (30 mg/kg) to rats produced marked injury and apoptosis, elevation of \ Bax\ protein expression, and inhibition\ of \ Bcl-2\ protein expression in the kidneys, which were reversed significantly by oral administration \ of RG (0.2 or 0.4 mg/kg).. The findings of our study indicate that RG may play an important role in protecting the kidneys through inhibiting\ apoptosis, \ Bax\ , and \ Bcl-2\ protein expression.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Carbamates; Cyclosporine; Hypoglycemic Agents; Kidney; Kidney Diseases; Kidney Tubules; Male; Piperidines; Proto-Oncogene Proteins c-bcl-2; Rats, Sprague-Dawley

The antidiabetic drugs glibenclamide, repaglinide, and nateglinide are well-known substrates for hepatic uptake transporters of the organic anion transporting polypeptide (OATP) family and metabolizing enzymes of the cytochrome P450 (CYP) 2C subfamily. The systemic exposure of these drugs varies substantially among individuals, impacted by genetic polymorphisms of transporters and metabolizing enzymes as well as drug-drug interactions. The use of the conventional in vitro-in vivo extrapolation (IVIVE) method was found to underestimate their hepatic intrinsic clearance (CL

Topics: Albumins; Carbamates; Cytochrome P-450 Enzyme System; Glyburide; HEK293 Cells; Hepatocytes; Humans; Hypoglycemic Agents; Liver; Liver-Specific Organic Anion Transporter 1; Metabolic Clearance Rate; Microsomes, Liver; Models, Biological; Nateglinide; Piperidines; Solute Carrier Organic Anion Transporter Family Member 1B3

Insulinotropic oral antidiabetics (OAD) such as sulfonylureas and (SU) glinides are among the frequently prescribed OAD. Side effects are the potential to induce hypoglycemias and weight gain. The aim was to assess the self-managing skills in case of a hypoglycemic event in an elderly type 2 diabetic patient population. In a 2-year period, 160 hospitalized patients (mean age 77.4 years) under insulinotrophic OAD were interviewed using a standardized questionnaire. Additionally, possible dementia was evaluated by using the Mini-Mental State Examination (MMSE) and the Clock-Drawing Test (CDT). The mean HbA1c was 7.6%. MMSE and CDT did intraindividually correlate well and 23.8% of the patients had moderate dementia (10 - 20 points MMSE), 13.1% had severe dementia (0 - 10 points MMSE) at the time of the survey. When under treatment with a sulfonylurea, only 16.0% of patients were aware of the potential hypoglycemia-inducing side effect. Moreover, only 11.8% of patients treated with a combination of a sulfonylurea and insulin knew this side effect of the OAD. The awareness of the side effects of repaglinide was 21.6% (without insulin therapy) versus 21.4% in the insulin-comedicated group. Only 42.6% of patients treated with sulfonylureas or repaglinide knew how to act in the case of hypoglycemia. Even under comedication with insulin, only in 41.2% of the respondents in the comedicated group knew how to take action if they were to experience hypoglycemia. Our findings raise concerns and demonstrate, that the self-managing skills in an elderly patient group are not good, which may become an increasing problem in an ageing population. The prescription or the re-prescription of insulinotropic OAD needs to be adapted to the current cognitive situation and re-evaluated regularly.

Topics: Aged; Aged, 80 and over; Aging; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Health Knowledge, Attitudes, Practice; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Self-Management; Sulfonylurea Compounds

The aim of this study was to determine the similarities and differences of type 2 diabetes mellitus (T2DM) treatment patterns in daily practice in 5 European countries and whether these reflect differences in guidelines.. Prescriptions for drugs used in diabetes treatment during a 5-year study period were obtained from electronic databases. Patients initiating T2DM treatment during the study period were included. An SAS analysis tool was developed to create episodes of use of drug classes, which resulted in treatment patterns.. A total of 253,530 patients initiating T2DM treatment during the study period were included; 52% to 55% were male, and the mean age ranged from 62 to 67 years. Metformin was the most common initial treatment in all countries. After initial therapy, most patients in the Netherlands, Spain, and the United Kingdom switched to a combination of metformin + a sulfonylurea derivative (SU). In Italy, metformin in combination with an SU was outnumbered by "other treatment," mainly because of repaglinide use. In France, treatments including dipeptidyl peptidase-4 inhibitors were most frequent as second- and fourth-line treatment. Metformin monotherapy was again most commonly observed as the third line of treatment in all countries. Fourth treatment was a combination of metformin + an SU in the Netherlands and Spain; in the United Kingdom and France, dipeptidyl peptidase-4 inhibitors were the most frequently used fourth line of treatment.. This study provides a comprehensive overview of T2DM treatment patterns among patients initiating T2DM treatment in 5 European countries. There were differences, especially regarding the uptake of newer incretin-based treatments, which are usually prescribed as a second and/or third treatment in agreement with local guidelines. These variations reflect the differences between the national guidelines of these countries.

Topics: Aged; Carbamates; Databases, Factual; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Drug Utilization; Europe; Female; Humans; Hypoglycemic Agents; Incretins; Male; Metformin; Middle Aged; Piperidines; Sulfonylurea Compounds

Repaglinide is a hypoglycemic drug, causing depolarization of the cell membrane, opening the voltage-gated calcium channels, and then increasing intracellular calcium in the pancreatic B cells by inhibition of the K-ATP-sensitive channels. Oocyte in vitro maturation (IVM) is influenced by different factors such as calcium signaling. In this study, we examined the effects of repaglinide on in vitro maturation and fertilization ability of mouse oocyte. Immature oocytes were isolated from female Naval Medical Research Institute mice which are 6-8 wk old mechanically and then cultured in 30 μl droplets of T6 medium with different concentrations of repaglinide. The control group did not receive repaglinide (R

Topics: Animals; Carbamates; Cleavage Stage, Ovum; Female; In Vitro Oocyte Maturation Techniques; Metaphase; Mice; Oocytes; Piperidines

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with a median survival time of only 14 months after treatment. It is urgent to find new therapeutic drugs that increase survival time of GBM patients. To achieve this goal, we screened differentially expressed genes between long-term and short-term survived GBM patients from Gene Expression Omnibus database and found gene expression signature for the long-term survived GBM patients. The signaling networks of all those differentially expressed genes converged to protein binding, extracellular matrix and tissue development as revealed in BiNGO and Cytoscape. Drug repositioning in Connectivity Map by using the gene expression signature identified repaglinide, a first-line drug for diabetes mellitus, as the most promising novel drug for GBM. In vitro experiments demonstrated that repaglinide significantly inhibited the proliferation and migration of human GBM cells. In vivo experiments demonstrated that repaglinide prominently prolonged the median survival time of mice bearing orthotopic glioma. Mechanistically, repaglinide significantly reduced Bcl-2, Beclin-1 and PD-L1 expression in glioma tissues, indicating that repaglinide may exert its anti-cancer effects via apoptotic, autophagic and immune checkpoint signaling. Taken together, repaglinide is likely to be an effective drug to prolong life span of GBM patients.

Topics: Animals; Carbamates; Cell Survival; Disease Models, Animal; Dose-Response Relationship, Drug; Glioblastoma; Humans; Mice; Mice, Inbred C57BL; Piperidines; Structure-Activity Relationship; Tumor Cells, Cultured

Quantitative analysis of transporter- and enzyme-mediated complex drug-drug interactions (DDIs) is challenging. Repaglinide (RPG) is transported into the liver by OATP1B1 and then is metabolized by CYP2C8 and CYP3A4. The purpose of this study was to describe the complex DDIs of RPG quantitatively based on unified physiologically based pharmacokinetic (PBPK) models using in vitro K

Topics: Biological Transport; Carbamates; Computer Simulation; Cyclosporine; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP2C8 Inhibitors; Cytochrome P-450 CYP3A; Drug Interactions; Enzyme Inhibitors; Gemfibrozil; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Models, Biological; Piperidines

Topics: Adult; Bosentan; Carbamates; Computer Simulation; Cytochrome P-450 CYP3A; Drug Interactions; Hepatobiliary Elimination; Humans; Itraconazole; Liver; Male; Models, Biological; Organic Anion Transporters; Pharmaceutical Preparations; Piperidines; Rifampin; Sulfonamides; Young Adult

Chronic unpredicted mild stress (CUMS)-induced depression could alter the pharmacokinetics of many drugs in rats, however, the underlying mechanism is not clear. In this work we studied the pharmacokinetics of repaglinide, and explored the role of glucocorticoid and adrenergic signaling pathway in regulating drug metabolizing enzymes (DMEs) in GK rats and BRL 3A cells. The plasma cortisol and epinephrine levels were increased, meanwhile the pharmacokinetics of repaglinide were altered significantly in depression model rats. Forty-nine genes in liver of model rats displayed significant difference comparing to control rats. The differentially expressed genes enriched in the drug metabolism and steroid hormone biosynthesis pathway significantly, and Nr1i3 matched 335 connectivity genes. CAR and Ugt1a1 protein expression were enhanced significantly in liver of model rats. The mRNA expression of Ugt1a1 and Nr1i2 were increased 2 and 4 times respectively with dexamethasone (DEX) and 8-Br-cAMP co-treatment in BRL 3A cells. The protein expression of PXR was up-regulated, too. However, RU486 reversed the up-regulated effect. The adrenergic receptor agonists had little impact on the DMEs in BRL 3A. Our data suggested that CUMS-induced depression might up-regulate DMEs expression via glucocorticoid signaling pathway, and accelerate the fate of the repaglinide in spontaneous diabetes rats.

Topics: Animals; Biosynthetic Pathways; Carbamates; Cell Line; Constitutive Androstane Receptor; Depression; Disease Models, Animal; Gene Expression Profiling; Gene Expression Regulation; Gene Regulatory Networks; Glucocorticoids; Liver; Male; Pharmacogenetics; Piperidines; Rats; Signal Transduction; Stress, Psychological

The purpose of the study was to enhance the solubility of the poorly water-soluble drug, Repaglinide using spray drying based solid dispersion technique by different carriers including Eudragit E100, hydroxyl propyl cellulose Mw 80 000 and poly vinyl pyrollidone K30. Optimization of the best formulation was carried out according to drug solubility, release profile, particle size and angle of repose of the solid dispersions. The optimized sample was characterized using X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The morphology of the dispersions was studied by SEM. The blood glucose lowering effect of spray dried solid dispersions was studied in normal and streptozocin-induced diabetic rats. The results showed that Eudragit E100 in 1:3 ratio could enhance drug solubility by 100-fold. DSC studies indicated a marked change in melting point of the drug possibly due to strong hydrogen bonds between the drug and Eudragit, while FT-IR study did not show obvious interactions between them. According to XRPD results Repaglinide converted to an amorphous state in the spray dried dispersions. Spray dried Repaglinide reduced the blood glucose level significantly during the 8 h of obtaining blood samples in comparison with untreated drug (p < 0.05).

Topics: Animals; Calorimetry, Differential Scanning; Carbamates; Diabetes Mellitus, Experimental; Hypoglycemic Agents; Piperidines; Rats; Solubility; Spectroscopy, Fourier Transform Infrared

Tropical starches from Dioscorea dumetorum (bitter) and Dioscorea oppositifolia (Chinese) yams were acetylated with acetic anhydride in pyridine medium and utilized as polymers for the delivery of repaglinide in microsphere formulations in comparison to ethyl cellulose. Acetylated starches of bitter and Chinese yams with degrees of substitution of 2.56 and 2.70 respectively were obtained. Acetylation was confirmed by FTIR,

Topics: Acetic Anhydrides; Acetylation; Carbamates; Cellulose; Dioscorea; Drug Carriers; Drug Compounding; Drug Liberation; Factor Analysis, Statistical; Hypoglycemic Agents; Kinetics; Microspheres; Particle Size; Piperidines; Plant Extracts; Pyridines; Solutions; Starch; Thermodynamics

Increasing evidence suggests that certain newer anti-diabetic drugs are associated with an increased risk of hospitalized heart failure (HHF). However, the potential risks associated with the use of sulfonylurea and glinide have not been carefully evaluated.. A retrospective cohort study using the Taiwan National Health Insurance claims database was conducted to examine the risks of HHF among newly diagnosed type 2 diabetic patients who initiated glinide, sulfonylurea, or acarbose therapy during 2006-2012. The outcome of interest was hospitalization due to heart failure after treatment initiation, defined by ICD-9-CM code. A Cox proportional hazard regression model was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) using acarbose as the reference group.. A total of 25,638 glinide, 272,140 sulfonylurea, and 29,376 acarbose initiators were included in the analysis. Patients who initiated glinide had the highest crude HHF incidence. In the analysis adjusted for baseline differences, a significantly higher risk of HHF was found for glinide (adjusted HR, 1.53; 95% CI, 1.24-1.88), but not for sulfonylurea (adjusted HR, 0.94; 95% CI, 0.80-1.11), as compared with acarbose. The elevated risk remained consistent across different subgroups of patients as well as several sensitivity analyses including exploring the impact of potential unmeasured confounding.. These findings indicated that, as compared with acarbose, glinide may be associated with a higher risk of HHF for type 2 diabetic patients. Further researchis needed to fully evaluate the risks and benefits of glinide therapy relative to other oral anti-diabetic agents.

Topics: Acarbose; Administration, Oral; Age Factors; Aged; Carbamates; Cohort Studies; Confidence Intervals; Databases, Factual; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Heart Failure; Hospital Mortality; Hospitalization; Humans; Hypoglycemic Agents; Incidence; Male; Middle Aged; Piperidines; Proportional Hazards Models; Retrospective Studies; Risk Assessment; Sex Factors; Sulfonylurea Compounds; Survival Rate; Taiwan

To enhance the oral antidiabetic effect of repaglinide (RG), a newly emerging approach, based on the combination of phospholipid complexation and micelle techniques, was employed. Repaglinide-phospholipid complex (RG-PLC) was prepared by the solvent-evaporation method then characterized using Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction (XPRD). The results revealed obvious disappearance of the characteristic peaks of the prepared RG-PLCs confirming the formation of drug-phospholipid complex. RG-PLC enriched micelles (RG-PLC-Ms) were prepared by the solvent-evaporation technique employing poloxamer 188 as surfactant. The prepared RG-PLC-Ms showed high drug encapsulation efficiencies (93.81-99.38%), with nanometric particle diameters (500.61-665.32nm) of monodisperse distribution and high stability (Zeta potential < -29.8mV). The in vitro release of RG from RG-PLC-Ms was pH-dependant according to the release media. A higher release pattern was reported in pH=1.2 compared to a more retarded release in pH=6.8 owing to two different kinetics of drug release. Oral antidiabetic effect of two optimized RG-PLC-M formulations was evaluated in an alloxan-induced diabetic rat model for 7-day treatment protocol. The two investigated formulations depicted normal blood glucose, serum malondialdehyde and insulin levels as well as an improved lipid profile, at the end of daily oral treatment, in contrast to RG marketed tablets implying enhanced antidiabetic effect of the drug. Hence, phospholipid-complex enriched micelles approach holds a promising potential for promoting the antidiabetic effect of RG.

Topics: Animals; Calorimetry, Differential Scanning; Carbamates; Chemistry, Pharmaceutical; Drug Carriers; Drug Delivery Systems; Drug Stability; Hypoglycemic Agents; Male; Micelles; Microscopy, Electron, Transmission; Phospholipids; Piperidines; Poloxamer; Rats; Rats, Wistar; Spectroscopy, Fourier Transform Infrared; Tablets; X-Ray Diffraction

Lesinurad is a selective uric acid reabsorption inhibitor approved for the treatment of hyperuricemia associated with gout in combination with xanthine oxidase inhibitors. In vitro assays indicate that lesinurad is an inducer of CYPs in the order CYP3A > CYP2C8 > CYP2C9 > CYP2C19 > CYP2B6 and an inhibitor of CYP2C8 and CYP2C9. To investigate the drug interaction potential of lesinurad, clinical drug interaction studies were conducted. Open-label studies in volunteers investigated the effects of single-/multiple-dose lesinurad on the pharmacokinetics of sildenafil and amlodipine (CYP3A4 induction), tolbutamide (CYP2C9 inhibition/induction), and repaglinide (CYP2C8 inhibition/induction). There was no apparent induction of CYP2C8 and CYP2C9 following repeated lesinurad administration, although no inhibition of CYP2C9 and modest inhibition of CYP2C8 were observed following single-dose lesinurad. Consistent with in vitro observations, lesinurad (200 mg once daily) was an inducer of CYP3A based on the effects on sildenafil exposure. Sildenafil exposure decreased by approximately 34% for C

Topics: Adult; Amlodipine; Area Under Curve; Carbamates; Cytochrome P-450 Enzyme System; Dose-Response Relationship, Drug; Drug Interactions; Gene Expression Regulation; Healthy Volunteers; Humans; In Vitro Techniques; Male; Middle Aged; Piperidines; Sildenafil Citrate; Thioglycolates; Tolbutamide; Triazoles; Young Adult

Even though ellagic acid has previously been valued in many models of cancer, so far its full mechanistic effect as a natural antiapoptotic agent in the prevention of type 2 diabetes complications has not been completely elucidated, which was the goal of this study. We fed albino rats a high-fat fructose diet (HFFD) for 2 months to induce insulin resistance/type 2 diabetes and then treated the rats with ellagic acid (10 mg/kg body weight, orally) and/or repaglinide (0.5 mg/kg body weight, orally) for 2 weeks. At the serum level, ellagic acid challenged the consequences of HFFD, significantly improving the glucose/insulin balance, liver enzymes, lipid profile, inflammatory cytokines, redox level, adipokines, ammonia, and manganese. At the tissue level (liver, pancreas, adipose tissue, and brain), ellagic acid significantly enhanced insulin signaling, autophosphorylation, adiponectin receptors, glucose transporters, inflammatory mediators, and apoptotic markers. Remarkably, combined treatment with both ellagic acid and repaglinide had a more pronounced effect than treatment with either alone. These outcomes give new insight into the promising molecular mechanisms by which ellagic acid modulates numerous factors induced in the progression of diabetes.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Biomarkers; Brain; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Ellagic Acid; Hyperglycemia; Hypoglycemic Agents; Inflammation Mediators; Insulin Resistance; Intra-Abdominal Fat; Liver; Male; Neurons; Oxidative Stress; Pancreas; Piperidines; Rats, Wistar

Repaglinide, an oral antidiabetic agent, has a rapid onset of action and short half-life of approximately 1h. Developing a controlled and prolonged release delivery system is required to maintain its therapeutic plasma concentration and to eliminate its adverse effects particularly hypoglycemia. The present study aimed to develop controlled release repaglinide loaded beads using sodium alginate and pectin with dual cross-linking for effective control of drug release. The prepared beads were characterized for size, percentage drug entrapment efficiency, in vitro drug release and the morphological examination using scanning electron microscope. For the comparative study, the release profile of a marketed conventional tablet of repaglinide (Prandin

Topics: Adhesiveness; Alginates; Carbamates; Delayed-Action Preparations; Drug Carriers; Drug Liberation; Epichlorohydrin; Glucuronic Acid; Hexuronic Acids; Hydrophobic and Hydrophilic Interactions; Kinetics; Mucous Membrane; Particle Size; Pectins; Piperidines; Temperature

Drug-drug interactions with insulin secretagogues are associated with increased risk of serious hypoglycemia in patients with type 2 diabetes. We aimed to systematically screen for drugs that interact with the five most commonly used secretagogues-glipizide, glyburide, glimepiride, repaglinide, and nateglinide-to cause serious hypoglycemia.. We screened 400 drugs frequently coprescribed with the secretagogues as candidate interacting precipitants. We first predicted the drug-drug interaction potential based on the pharmacokinetics of each secretagogue-precipitant pair. We then performed pharmacoepidemiologic screening for each secretagogue of interest, and for metformin as a negative control, using an administrative claims database and the self-controlled case series design. The overall rate ratios (RRs) and those for four predefined risk periods were estimated using Poisson regression. The RRs were adjusted for multiple estimation using semi-Bayes method, and then adjusted for metformin results to distinguish native effects of the precipitant from a drug-drug interaction.. We predicted 34 pharmacokinetic drug-drug interactions with the secretagogues, nine moderate and 25 weak. There were 140 and 61 secretagogue-precipitant pairs associated with increased rates of serious hypoglycemia before and after the metformin adjustment, respectively. The results from pharmacokinetic prediction correlated poorly with those from pharmacoepidemiologic screening.. The self-controlled case series design has the potential to be widely applicable to screening for drug-drug interactions that lead to adverse outcomes identifiable in healthcare databases. Coupling pharmacokinetic prediction with pharmacoepidemiologic screening did not notably improve the ability to identify drug-drug interactions in this case.

Topics: Area Under Curve; Carbamates; Cyclohexanes; Databases, Factual; Diabetes Mellitus, Type 2; Drug Interactions; Glipizide; Glyburide; Humans; Hypoglycemia; Hypoglycemic Agents; Medical Informatics; Nateglinide; Pharmacoepidemiology; Phenylalanine; Piperidines; Sulfonylurea Compounds

We have previously reported that the microsomal activities of CYP2C8 and CYP3A4 largely depend on the buffer condition used in in vitro metabolic studies, with different patterns observed between the 2 isozymes. In the present study, therefore, the possibility of buffer condition dependence of the fraction metabolized by CYP2C8 (fm2C8) for repaglinide, a dual substrate of CYP2C8 and CYP3A4, was estimated using human liver microsomes under various buffer conditions. Montelukast and ketoconazole showed a potent and concentration-dependent inhibition of CYP2C8-mediated paclitaxel 6α-hydroxylation and CYP3A4-mediated triazolam α-hydroxylation, respectively, without dependence on the buffer condition. Repaglinide depletion was inhibited by both inhibitors, but the degree of inhibition depended on buffer conditions. Based on these results, the contribution of CYP2C8 in repaglinide metabolism was estimated to be larger than that of CYP3A4 under each buffer condition, and the fm2C8 value of 0.760, estimated in 50 mM phosphate buffer, was the closest to the value (0.801) estimated in our previous modeling analysis based on its concentration increase in a clinical drug interaction study. Researchers should be aware of the possibility of buffer condition affecting the estimated contribution of enzyme(s) in drug metabolism processes involving multiple enzymes.

Topics: Acetates; Buffers; Carbamates; Cyclopropanes; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inducers; Cytochrome P-450 Enzyme Inhibitors; Drug Interactions; Humans; Hypoglycemic Agents; Ketoconazole; Microsomes, Liver; Piperidines; Quinolines; Sulfides

Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites were studied. Major organs (brain, lung, liver, kidney and muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed the same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. In addition, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement.

Topics: Animals; Carbamates; Chromatography, High Pressure Liquid; Hypoglycemic Agents; Male; Mice; Mice, Inbred BALB C; Microinjections; Microtomy; Piperidines; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Tissue Distribution

Repaglinide is a short-acting insulin secretagogue with high interindividual variability in pharmacokinetics due to genetic polymorphisms. Little is known about repaglinide overdoses, both with respect to pharmacokinetics and appropriate management. Given its short serum half-life of less than 1 h, hypoglycemic effects of repaglinide are expected to cease within a few hours post-ingestion.. A 15-year-old girl ingested 10.5 mg of repaglinide in a suicide attempt. Few hours later, she developed a strong food craving, nausea, abdominal pain, and a headache. The lowest recorded serum glucose was 44 mg/dl (2.4 mmol/l) 14 h post-ingestion. Using liquid chromatography-mass spectrometry, we detected repaglinide serum levels of 5.3, 2.6, and 1.0 ng/ml at 14, 20, and 26 h post-ingestion, respectively.. This case illustrates that in the context of overdose, repaglinide can lead to prolonged hypoglycemia. We therefore recommend glucose monitoring and observation for 24 h in all patients who remain hypoglycemic or show symptoms of hypoglycemia for an unusually long period of time.

Topics: Adolescent; Blood Glucose; Carbamates; Chromatography, Liquid; Drug Overdose; Female; Half-Life; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Piperidines; Tandem Mass Spectrometry

Deregulated protein and Ca2+ homeostasis underlie synaptic dysfunction and neurodegeneration in Huntington disease (HD); however, the factors that disrupt homeostasis are not fully understood. Here, we determined that expression of downstream regulatory element antagonist modulator (DREAM), a multifunctional Ca2+-binding protein, is reduced in murine in vivo and in vitro HD models and in HD patients. DREAM downregulation was observed early after birth and was associated with endogenous neuroprotection. In the R6/2 mouse HD model, induced DREAM haplodeficiency or blockade of DREAM activity by chronic administration of the drug repaglinide delayed onset of motor dysfunction, reduced striatal atrophy, and prolonged life span. DREAM-related neuroprotection was linked to an interaction between DREAM and the unfolded protein response (UPR) sensor activating transcription factor 6 (ATF6). Repaglinide blocked this interaction and enhanced ATF6 processing and nuclear accumulation of transcriptionally active ATF6, improving prosurvival UPR function in striatal neurons. Together, our results identify a role for DREAM silencing in the activation of ATF6 signaling, which promotes early neuroprotection in HD.

Topics: Activating Transcription Factor 6; Animals; Carbamates; CHO Cells; Corpus Striatum; Cricetulus; Disease Models, Animal; HEK293 Cells; HeLa Cells; Humans; Huntington Disease; Kv Channel-Interacting Proteins; Mice; Neurons; Piperidines; Repressor Proteins; Signal Transduction

Diabetes mellitus is one of the serious global health problems affecting a significant proportion of both developed and developing countries. Overproduction of free radicals and oxidative stress has been associated with the development of diabetic complications. In the present study, the antioxidant effects of metformin (MET), glibenclamide (GLI), and repaglinide (REP) were evaluated in alloxan-induced diabetic rats. The findings from this study may possibly help in understanding the efficacy of these standard drugs in managing the complications arising from diabetes mellitus (DM). Alloxan (130 mg/kg BW) was administered as a single dose to induce diabetes. Four (4) groups of rats (n = 6) were used; group 1 served as diabetic control while groups 2, 3, and 4 were the diabetic test groups that received MET (25 mg/kg), GLI (2.5 mg/kg), and REP (0.5 mg/kg), respectively. The result of the study showed significant (p < 0.05) improvement in the altered antioxidant enzymes (SOD, CAT) and GSH concentration in diabetic treated rats compared with the diabetic control group. MET and REP produced significant effect on the MDA concentration while GLI showed insignificant reduction in the MDA concentration compared with the diabetic control. Findings from this study suggest that the administration of MET, GLI, and REP exerts significant antioxidant effects in alloxan-induced diabetic rats, thus contributing to the protective effect against oxidative stress-induced damage during diabetic complications.

Topics: Alloxan; Animals; Antioxidants; Biomarkers; Blood Glucose; Carbamates; Catalase; Diabetes Complications; Diabetes Mellitus, Experimental; Glutathione; Glyburide; Hypoglycemic Agents; Lipid Peroxidation; Male; Malondialdehyde; Metformin; Oxidative Stress; Piperidines; Rats; Superoxide Dismutase

Hyperglycemia induces damage of vascular endothelial cells leading to diabetic complications. We investigated the effects of insulinotropic compounds and elevated glucose on endothelial cells in the absence or presence of vascular endothelial growth factor (VEGF).. Human umbilical vein endothelial cells (HUVECs) were treated with glibenclamide, repaglinide and insulinotropic imidazolines at high glucose concentration in the presence or absence of VEGF and viability, proliferation and nitric oxide production were measured. Hyperglycemia inhibited pro-survival effects of VEGF on endothelial cells. Glibenclamide and repaglinide decreased HUVEC viability at elevated glucose concentration in the absence but not in the presence of VEGF, without affecting HUVEC proliferation. Repaglinide also had some positive influence on HUVEC function elevating NO production in the presence of VEGF. Imidazolines showed different activities on endothelial cell survival. Efaroxan diminished HUVEC viability at elevated glucose concentration in the presence, however not in the absence of VEGF, while RX871024 decreased HUVEC survival regardless of the presence of VEGF.. Our data demonstrate an important interplay between the actual insulinotropic compounds, VEGF and ambient glucose concentration affecting the survival of the vascular endothelial cells. Consequently, this interplay needs to be taken into consideration when designing novel oral antidiabetic compounds.

Topics: Benzofurans; Carbamates; Cell Proliferation; Cell Survival; Cells, Cultured; Dimethyl Sulfoxide; Glucose; Glyburide; Human Umbilical Vein Endothelial Cells; Humans; Hypoglycemic Agents; Imidazoles; Indoles; Nitric Oxide; Piperidines; Vascular Endothelial Growth Factor A

Previous pharmacogenomic studies of oral anti-diabetic drugs have primarily focused on the effect of a single site. This study aimed to examine the joint effects of multiple loci on repaglinide or rosiglitazone efficacy in newly diagnosed type 2 diabetes mellitus (T2DM) patients. A total of 209 newly diagnosed T2DM patients were randomly assigned to treatment with repaglinide or rosiglitazone for 48 weeks. The reductions in fasting glucose (ΔFPG), 2h glucose (Δ2hPG) and glycated hemoglobin (ΔHbA1c) levels were significantly associated with genetic score that was constructed using the sum of the effect alleles both in the repaglinide (P = 0.0011, 0.0002 and 0.0067, respectively) and rosiglitazone cohorts (P = 0.0002, 0.0014 and 0.0164, respectively) after adjusting for age, gender, body mass index and dosage. Survival analyses showed a trend towards a greater attainment rate of target HbA1c level in individuals with a high genetic score in the repaglinide cohort and rosiglitazone cohort (Plog-rank = 0.0815 and 0.0867, respectively) when the attainment of treatment targets were defined as more than 20% decrease of FPG, 2hPG, and HbA1c levels after treatment. In conclusion, we identified the joint effects of several T2DM-related loci on the efficacy of oral anti-diabetic drugs; moreover, we built a model to predict the drug efficacy.

Topics: Administration, Oral; Adult; Alleles; Asian People; Blood Glucose; Body Mass Index; Carbamates; China; Diabetes Mellitus, Type 2; Drug Administration Schedule; Female; Genetic Loci; Genotype; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Linear Models; Male; Middle Aged; Piperidines; Polymorphism, Single Nucleotide; Rosiglitazone; Thiazolidinediones

The aim of the present study was to evaluate the long-term efficacy and safety of adding repaglinide in patients with type 2 diabetes mellitus whose blood glucose levels were not sufficiently controlled by treatment with a dipeptidyl peptidase-4 inhibitor, sitagliptin, in addition to diet and exercise therapies.. This was a multicenter, uncontrolled, dose-titration study with a treatment period of 52 weeks. The primary end-point was the change in glycated hemoglobin levels from baseline.. The glycated hemoglobin level was 7.43 ± 0.57% (mean ± standard deviation) at baseline, and decreased to 6.93 ± 0.91% at the end of the study. The mean changes in glycated hemoglobin levels at 4 weeks and at the end of the study were -0.44 ± 0.28% and -0.50 ± 0.82%, respectively. The glycated hemoglobin-lowering effect was maintained for 52 weeks. The rate of adverse events was 86.0% (86/100), and there were 352 adverse events. The rate of adverse drug reactions was 21.0% (21/100). Hypoglycemia was reported in 5.0% (5/100) of patients, but there was no incidence of 'major hypoglycemia'.. Combination therapy with repaglinide and sitagliptin was considered effective for a long term without clinical safety problems in patients with type 2 diabetes mellitus.

Topics: Adult; Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Sitagliptin Phosphate

Solid lipid nanoparticles (SLNs) are highly susceptible to phagocytosis by reticuloendothelial system (RES). To overcome this problem, a novel hydrogel-coated SLNs structure was developed and evaluated in this study.. Solid lipid nanoparticles surface was coated with chitosan, via electrostatic attraction with the negatively charged SLNs surface. The resulting polymer-coated SLNs then hosted an inorganic poly-anionic agent, tripolyphosphate, to form the final lipohydrogel structure.. Compared with the bare SLNs, lipohydrogel nanoparticles (LHNs) showed a significant increase in size and zeta potential. The release profile showed lower burst release and lower release rate for LHNs compared with SLNs. LHNs nanoparticles released the model antidiabetic drug, repaglinide, in a more sustained manner with lower burst effect compared with the corresponding SLN structure. Cytotoxicity studies via cell culture and MTT assay revealed no bio-toxicity of the SLNs and LHNs. In addition, intravenous administration of repaglinide-loaded SLNs and LHNs in rats showed longer drug residence time in circulation for LHNs, a trend also evident for the blood glucose level-time profile.. The particle size, zeta potential, FTIR and microscopy data demonstrated the formation of the supposed lipohydrogel nanoparticles. All these benefits of LHNs propose it as a promising candidate for controlled release of the drugs.

Topics: Administration, Intravenous; Animals; Blood Glucose; Carbamates; Cell Line; Cell Survival; Chitosan; Delayed-Action Preparations; Drug Carriers; Drug Compounding; Fibroblasts; Hydrogels; Hypoglycemic Agents; Lipids; Male; Mice; Nanotechnology; Particle Size; Piperidines; Polyphosphates; Rats, Sprague-Dawley; Solubility; Spectroscopy, Fourier Transform Infrared; Static Electricity; Surface Properties; Technology, Pharmaceutical

Ritonavir is an antiretroviral drug to treat HIV AIDS and inhibits cytochrome P450 3A4. To treat diabetes mellitus in HIV, repaglinide is coadministered with ritonavir in the clinic. Multiple cytochrome P450 (CYP) isoforms are involved in the metabolism of repaglinide like CYP2C8 and CYP 3A4. In order to predict and understand drug-drug interactions of these two drugs, the pharmacokinetics and pharmacodynamics (PK/PD) of repaglinide and ritonavir were studied in normal, diabetic and hepatic impaired rats. The purpose of the study was to assess the influence of ritonavir on the PK/PD of repaglinide in rats with normal, diabetic and impaired hepatic function.. Human oral therapeutic doses of ritonavir and repaglinide were extrapolated to rats based on the body surface area. Ritonavir (20 mg/kg, p.o.), alone and along with repaglinide (0.5 mg/kg, p.o.), was given to normal, diabetic and hepatic impaired rats, and the PK/PD were studied.. The pharmacokinetic parameters like peak plasma concentration (Cmax), area under the plasma concentration time profile (AUC) and elimination half life of repaglinide were significantly (p<0.0001) increased when compared to repaglinide control rats. The repaglinide clearance (CL) was significantly (p<0.0001) decreased in the presence of ritonavir treatment. In the presence of ritonavir, repaglinide hypoglycemic activity was increased significantly (p<0.0005) when compared with repaglinide control group.. The significant difference in the PK/PD changes have been due to the increased plasma exposure and decreased total body clearance of repaglinide, which may be due to the inhibition of the CYP P450 metabolic system and organic anion-transporting polypeptide transporter by ritonavir.

Topics: Alloxan; Animals; Blood Glucose; Carbamates; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Diabetes Mellitus, Experimental; Drug Synergism; Male; Piperidines; Rats; Ritonavir

Repaglinide (RPG) is a fast-acting prandial glucose regulator. It acts by stimulating insulin release from pancreatic β-cells. Recurrent dosing of RPG before each meal is burdensome remedy. Hence the plan of the present study was to evaluate nanoemulsion as a hopeful carrier for RPG for persistent hypoglycemic effect. The drug was incorporated into oil phase of nanoemulsion to give improved biopharmaceutical properties as compared to the lipid-based systems. Pseudo ternary phase diagrams were prepared by aqueous titration method. Formulations were selected at a difference of 5% w/w of oil from the o/w nanoemulsion region of phase diagrams. The optimized nanoemulsion formulation constituted sefsol-218 (5% v/v) as an oil phase, 30% v/v of Tween-80 and transcutol as a surfactant and co-surfactant to restrain nanodroplet size and low viscosity and distilled water (65%). In vitro dissolution studies showed higher drug release (98.22%), finest droplet size (76.23 nm), slightest polydispersity value (0.183), least viscosity (21.45 cps) and immeasurable dilution capability from the nanoemulsion as compared with existing oral tablet formulation. The optimized RPG nanoemulsion formulation showed better hypoglycemic effect in comparison to tablet formulation in experimental diabetic rats. No significant variations were also observed in the optimized formulation when subjected to accelerated stability study at different temperature and relative humidity over a period of 3 months.

Topics: Administration, Oral; Animals; Biopharmaceutics; Carbamates; Diabetes Mellitus, Experimental; Drug Stability; Emulsions; Hypoglycemic Agents; Lipids; Nanoparticles; Piperidines; Polysorbates; Rats; Solubility

A rapid, simple, and precise RPLC method was developed for the simultaneous determination of the widely used oral antidiabetic, metformin hydrochloride (MTF), with some commonly coadministered oral antidiabetics from different pharmacological classes-glipizide (GPZ), pioglitazone hydrochloride (PGZ), glimepiride (GLM), and repaglinide (RPG)-in bulk, laboratory-prepared mixtures and pharmaceutical formulations in the presence of metformin-reported impurity [1-cyanoguanidine (CNG)]. Chromatographic separation was achieved using isocratic elution mode with a mobile phase of acetonitrile: 0.02 M potassium dihydrogen phosphate (pH 3.17; 50-50, v/v) flowing through a CN Phenomenex column (Phenosphere Next, 250 × 4.6 mm, 5 μm) at a rate of 1.5 mL/min at ambient temperature. UV detection was carried out at 220 nm. The method was validated according to International Conference on Harmonization guidelines. Linearity, accuracy, and precision were satisfactory for concentration ranges: 0.175-350 μg/mL for MTF, 0.0525-105 μg/mL for GPZ, 0.125-250 μg/mL for PGZ, and 0.05-100 μg/mL for GLM and RPG. Correlation coefficients were >0.99 for all analytes. LOQs were 0.009 μg/mL for MTF, 0.009 μg/mL for GPZ, 0.04 μg/mL for GLM, 0.124 μg/mL for PGZ, and 0.044 μg/mL for RPG. The developed method is specific, accurate, and suitable for the QC and routine analysis of the cited drugs in their pharmaceutical products.

Topics: Carbamates; Chromatography, High Pressure Liquid; Drug Contamination; Glipizide; Guanidines; Hypoglycemic Agents; Metformin; Pioglitazone; Piperidines; Sulfonylurea Compounds; Thiazolidinediones

CYP2C8 is involved in the metabolic clearance of several important drugs and recent reports have shown that acyl glucuronides of gemfibrozil and clopidogrel are potent time-dependent inhibitors of CYP2C8 activity. In the present study, the inhibitory effect of steviol acyl glucuronide (SVAG), a circulating metabolite formed after the ingestion of rebaudioside A, was investigated using in vitro and in vivo systems. Results indicated that SVAG was a reversible but not a time-dependent inhibitor of CYP2C8-mediated paclitaxel 6α-hydroxylation. SVAG was also capable of inhibiting CYP2C8-mediated repaglinide 3'-hydroxylation in human liver microsomes and recombinant human CYP2C8, with Ki values of 15.8 μM and 11.6 μM, respectively. In contrast, SVAG did not exhibit inhibitory effect on CYP2C8 activity in rat liver microsomes. In addition, co-administration of rebaudioside A with repaglinide in rats did not lead to AUC and Cmax changes of repaglinide. Although mathematic prediction using a simplified mechanistic model revealed a moderate interaction potential between repaglinide and SVAG, cautions should be given to patients with hypoglycemia if repaglinide and rebaudioside A are used in combination for the blood sugar control.

Topics: Animals; Carbamates; Chromatography, Liquid; Cytochrome P-450 CYP2C8; Diterpenes, Kaurane; Glucuronides; Humans; Hydroxylation; Male; Microsomes, Liver; Paclitaxel; Piperidines; Rats; Rats, Sprague-Dawley; Tandem Mass Spectrometry

In present investigation, an innovative attempt has been made to enhance the solubility and dissolution rate of Repaglinide (RPGD) using hydrothermally treated water insoluble dietary bamboo fibers (HVBF) as potential nutraceutical used in the treatment of diabetes mellitus. RPGD was selected as a model drug due to its low aqueous solubility and dissolution rate. Characterization of HVBF demonstrated the outstanding features like high surface area, maximum drug loading and increase dissolution rate and making HVBF as an excellent drug carrier. RHVBF (Repaglinide loaded HVBF) tablets were prepared using direct compression method. Pre and post-compression parameters for blend and tablets were studied and found within acceptable limits. RHVBF and tablet showed significantly improved dissolution rate, when compared with pure crystalline RPGD, physical mixture, RVBF and commercial marketed tablet. This fact was further supported by FT-IR, DSC, XRPD and FESEM studies followed by in-vitro drug release profile. Stability studies showed no changes after exposing to accelerated conditions for a period of 3 months with respect to physical characteristics and in-vitro drug release studies. In a nut shell, it can be concluded that HVBF is a novel, smart and promising carrier for poorly water soluble drugs, when administered orally.

Topics: Carbamates; Cellulose; Chemical Phenomena; Dietary Fiber; Drug Carriers; Drug Liberation; Drug Stability; In Vitro Techniques; Piperidines; Sasa; Solubility; Tablets

We investigated the vasorelaxant effect of repaglinide and its related signaling pathways using phenylephrine (Phe)-induced pre-contracted aortic rings. Repaglinide induced vasorelaxation in a concentration-dependent manner. The repaglinide-induced vasorelaxation was not affected by removal of the endothelium. In addition, application of a nitric oxide synthase inhibitor (L-NAME) and a small-conductance Ca(2+)-activated K(+) (SKCa) channel inhibitor (apamin) did not alter the vasorelaxant effect of repaglinide on endothelium-intact arteries. Pretreatment with an adenylyl cyclase inhibitor (SQ 22536) or a PKA inhibitor (KT 5720) effectively reduced repaglinide-induced vasorelaxation. Also, pretreatment with a guanylyl cyclase inhibitor (ODQ) or a PKG inhibitor (KT 5823) inhibited repaglinide-induced vasorelaxation. However, pretreatment with a voltage-dependent K(+) (Kv) channel inhibitor (4-AP), ATP-sensitive K(+) (KATP) channel inhibitor (glibenclamide), large-conductance Ca(2+)-activated K(+) (BKCa) channel inhibitor (paxilline), or the inwardly rectifying K(+) (Kir) channel inhibitor (Ba(2+)) did not affect the vasorelaxant effect of repaglinide. Furthermore, pretreatment with a Ca(2+) inhibitor (nifedipine) and a sarco-endoplasmic reticulum Ca(2+)-ATPase (SERCA) inhibitor (thapsigargin) did not affect the vasorelaxant effect of repaglinide. The vasorelaxant effect of repaglinide was not affected by elevated glucose (50mM). Based on these results, we conclude that repaglinide induces vasorelaxation via activation of adenylyl cyclase/PKA and guanylyl cyclase/PKG signaling pathways independently of the endothelium, K(+) channels, Ca(2+) channels, and intracellular Ca(2+) ([Ca(2+)]i).

Topics: Animals; Aorta; Carbamates; Cyclic AMP-Dependent Protein Kinases; Cyclic GMP-Dependent Protein Kinases; Dose-Response Relationship, Drug; Endothelium, Vascular; Glucose; Hypoglycemic Agents; Male; Muscle, Smooth, Vascular; Phenylephrine; Piperidines; Rabbits; Signal Transduction; Vasodilation; Vasodilator Agents

The importance of transporter proteins for the disposition of drugs has become increasingly apparent during the past decade. A noted drug-drug interaction risk is the inhibition of organic anion-transporting polypeptides (OATPs), key transporters for the liver uptake of the widely used statins. We show here the development of a ligand-based in silico model for interaction with OATP1B1, an important representative of the OATP family. The model is based on a structural overlay of 6 known OATP1B1 inhibitors. A data set of about 150 compounds with published OATP1B1 inhibition data was compared to the resulting "transportophor," and a similarity threshold was defined to distinguish between active and inactive molecules. In addition, using a statistical model based on physicochemical properties of the compounds as prefilter was found to enhance the overall predictivity of the model (final accuracy 0.73, specificity 074, and sensitivity 0.71, based on 126 compounds). The combined model was validated using an in-house data set (accuracy, specificity, and sensitivity were 0.63, 0.59, and 0.78, respectively; 62 compounds). The model gives also a structural overlay to the most similar template enabling visualization of where a change in a given structure might reduce the interaction with the transporter.

Topics: Carbamates; Computer Simulation; Databases, Factual; Drug Design; Drug Interactions; HEK293 Cells; Humans; Liver-Specific Organic Anion Transporter 1; Models, Chemical; Piperidines; Risk

Correct diagnosis of Maturity-Onset Diabetes of the Young (MODY) is based on genetic tests requiring an appropriate subject selection by clinicians. Mutations in the insulin (INS) gene rarely occur in patients with MODY. This study is aimed at determining the genetic background and clinical phenotype in patients with suspected MODY. 34 patients with suspected MODY, negative for mutations in the GCK, HNF1α, HNF4α, HNF1β and PDX1 genes, were screened by next generation sequencing (NGS). A heterozygous INS mutation was identified in 4 members of the same family. First genetic tests performed identified two heterozygous silent nucleotide substitutions in MODY3/HNF1α gene. An ineffective attempt to suspend insulin therapy, administering repaglinide and sulphonylureas, was made. DNA was re-sequenced by NGS investigating a set of 102 genes. Genes implicated in the pathway of pancreatic β-cells, candidate genes for type 2 diabetes mellitus and genes causative of diabetes in mice were selected. A novel heterozygous variant in human preproinsulin INS gene (c.125T > C) was found in the affected family members. The new INS mutation broadens the spectrum of possible INS phenotypes. Screening for INS mutations is warranted not only in neonatal diabetes but also in MODYx patients and in selected patients with type 1 diabetes mellitus negative for autoantibodies. Subjects with complex diseases without a specific phenotype should be studied by NGS because Sanger sequencing is ineffective and time consuming in detecting rare variants.

Topics: Adolescent; Animals; Carbamates; Child; Diabetes Mellitus, Type 2; Female; Heterozygote; High-Throughput Nucleotide Sequencing; Humans; Insulin; Insulin-Secreting Cells; Male; Mice; Mutation; Pedigree; Piperidines; Regulatory Factor X Transcription Factors

We report three Caucasian patients affected by gout and type 2 diabetes, who were treated with the recombinant nonglycosylated human interleukin-1 receptor antagonist anakinra (100 mg/day subcutaneously) after an unsatisfactory or incomplete response to urate-lowering therapy, colchicine, nonsteroidal anti-inflammatory drugs, and prednisone. The remarkable clinical improvement in joint symptoms within 24 h and in glycemic control during a 6-month period gives anakinra a potential therapeutic role in the management of gout and type 2 diabetes. When anakinra was discontinued, a gout attack occurred within 3-25 days in all three patients. The contribution of anakinra in the treatment of such syndromes is encouraging, but requires further studies to establish its long-term efficacy.

Topics: Aged; Aged, 80 and over; Allopurinol; Anti-Inflammatory Agents, Non-Steroidal; Antirheumatic Agents; Blood Glucose; Carbamates; Colchicine; Diabetes Mellitus, Type 2; Febuxostat; Glycated Hemoglobin; Gout; Gout Suppressants; Humans; Hyperuricemia; Hypoglycemic Agents; Insulin; Interleukin 1 Receptor Antagonist Protein; Metformin; Middle Aged; Piperidines; Treatment Outcome; Uric Acid

Repaglinide (RG) is an efficient antihyperglycemic drug; however, due to its short half-life, patients are required to take the marketed products several times a day, which compromises the therapeutic effects. The present study was conducted to develop a hydrophilic sustained release matrix tablet for RG with the aims of prolonging its action time, reducing the required administration times and side effects and improving patient adherence. The matrix tablets were fabricated by a direct compression method, the optimized formulation for which was obtained by screening the factors that affected the drug release. Moreover, studies of the pharmacokinetics and hypoglycemic activity as measured by glucose assay kits were performed in dogs. Sustained drug releases profiles over 10h and a reduced influence of medium pHs on release were achieved with the optimized formulation; moreover, the in vivo performance of extended release formulation was also examined, and better absorption, a one-fold decrease in Cmax, a two-fold increase of Tmax and a prolonged hypoglycemic effect compared to the marketed product were observed. In conclusion, sustained RG release and prolonged action were observed with present matrix tablets, which therefore provide a promising formulation for T2D patients who require long-term treatment.

Topics: Animals; Blood Glucose; Carbamates; Delayed-Action Preparations; Dogs; Drug Liberation; Hypoglycemic Agents; Piperidines; Tablets

Metformin is the first-line treatment for most patients with type 2 diabetes but many patients need additional treatment with insulin secretagogues (IS) to achieve glycemic control. We aimed to compare mortality and cardiovascular risk among users of metformin in combination with pharmacologically different ISs.. Using nationwide administrative Danish registries, we followed all individuals without prior stroke or myocardial infarction who initiated metformin and an IS from 1997 through 2009. Rate ratios (RR) of all-cause mortality, cardiovascular death, and a composite of myocardial infarction, stroke, or cardiovascular death were compared between user groups using time-dependent multivariable Poisson regression models. The most common combination, glimepiride+metformin, was used as reference.. A total of 56,827 patients were included, 56% male, the mean age was 61 ± 12.5 years, and median duration of prior monotherapy was 2.2 (inter quartile range 0.5-4.5) years. Crude incidence rates of mortality for combinations of ISs with metformin were; 15.4 (repaglinide), 28.1 (glipizide), 23.7 (glibenclamide), 21.1 (gliclazide), 20.7 (glimepiride), 27.7 (tolbutamide) deaths per 1000 person years. In adjusted analysis, the associated mortality risk was similar for users of gliclazide+metformin (RR=1.01 [0.88-1.15]), repaglinide+metformin (RR=0.81 [0.62-1.05]), glibenclamide+metformin (RR=0.98 [0.87-1.10]), and tolbutamide+metformin (RR=1.04 [0.85-1.28]). Users of glipizide+metformin was associated with increased all-cause mortality (RR=1.16 [1.02-1.32], p=0.02), cardiovascular death (RR=1.21 [1.01-1.46], p=0.04), and the combined endpoint (RR=1.20 [1.06-1.36, p=0.005).. Most ISs in combination with metformin were associated with similar mortality and cardiovascular risk. Whether glipizide is associated with increased risk compared with other ISs when used in combinations with metformin warrants further study.

Topics: Aged; Carbamates; Cardiovascular Diseases; Denmark; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Gliclazide; Glipizide; Glyburide; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Morbidity; Myocardial Infarction; Piperidines; Registries; Retrospective Studies; Risk Factors; Stroke; Sulfonylurea Compounds; Tolbutamide

To evaluate the association between insulin secretagogues and adverse cardiovascular sequelae in type 2 diabetes patients hospitalized for ischemic heart disease (IHD).. Administrative health records from Alberta, Canada between 1998 and 2010 were used to identify 2,254 gliclazide, 3,289 glyburide and 740 repaglinide users prior to an IHD-related hospitalization. Multivariable Cox regression models were used to compare the 30-day risk of a composite outcome of all-cause mortality or new onset of atrial fibrillation, stroke, heart failure or myocardial infarction according to insulin secretagogue use.. Mean (SD) age was 76.1 (6.9) years, and 60.7% were men. The composite outcome occurred in 322 (30.2%) gliclazide users, 455 (28.1%) glyburide users and 81 (23.4%) repaglinide users within 30 days of IHD hospitalization. There were no differences in risk for glyburide use (adjusted hazard ratio [aHR] 0.91; 95% confidence interval [CI] 0.78-1.05) or repaglinide use (aHR 0.80; 95% CI 0.63-1.03) compared to gliclazide. Similar results were observed in analyses for each element of the composite outcome.. In older patients with type 2 diabetes hospitalized for IHD, prior use of gliclazide, glyburide, or repaglinide appears to be associated with a similar risk of adverse cardiovascular sequelae.

Topics: Aged; Aged, 80 and over; Alberta; Blue Cross Blue Shield Insurance Plans; Carbamates; Cardiovascular Diseases; Cohort Studies; Databases, Factual; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Cardiomyopathies; Female; Gliclazide; Glyburide; Hospitalization; Humans; Hypoglycemic Agents; Male; Myocardial Ischemia; Piperidines; Proportional Hazards Models; Retrospective Studies; Risk; Universal Health Insurance

The present work was undertaken with the objectives of improving the dissolution velocity, related oral bioavailability, and minimizing the fasted/fed state variability of repaglinide, a poorly water-soluble anti-diabetic active by exploring the principles of nanotechnology. Nanocrystal formulations were prepared by both top-down and bottom-up approaches. These approaches were compared in light of their ability to provide the formulation stability in terms of particle size. Soluplus® was used as a stabilizer and Kolliphor™ E-TPGS was used as an oral absorption enhancer. In vitro dissolution profiles were investigated in distilled water, fasted and fed state simulated gastric fluid, and compared with the pure repaglinide. In vivo pharmacokinetics was performed in both the fasted and fed state using Wistar rats. Oral hypoglycemic activity was also assessed in streptozotocin-induced diabetic rats. Nanocrystals TD-A and TD-B showed 19.86 and 25.67-fold increase in saturation solubility, respectively, when compared with pure repaglinide. Almost 10 (TD-A) and 15 (TD-B)-fold enhancement in the oral bioavailability of nanocrystals was observed regardless of the fasted/fed state compared to pure repaglinide. Nanocrystal formulations also demonstrated significant (p < 0.001) hypoglycemic activity with faster onset (less than 30 min) and prolonged duration (up to 8 h) compared to pure repaglinide (after 60 min; up to 4 h, respectively).

Topics: Animals; Biological Availability; Carbamates; Food-Drug Interactions; Hypoglycemic Agents; Male; Nanoparticles; Piperidines; Rats; Rats, Wistar

A high-throughput bioanalytical method using 96-blade thin film microextraction (TFME) and LC-MS/MS for the analysis of repaglinide (RPG) and two of its main metabolites was developed and used for an in vitro metabolism study.. The target analytes were extracted from human microsomal medium by a 96-blade-TFME system employing the low-cost prototype 'SPME multi-sampler' using C18 coating. Method validation showed recoveries around 90% for all analytes and was linear over the concentration range of 2-1000 ng ml(-1) for RPG and of 2-500 ng ml(-1) for each RPG metabolite.. The method was applied to an in vitro metabolism study of RPG employing human liver microsomes and proved to be very useful for this purpose.

Topics: Carbamates; Chromatography, Liquid; Humans; Hypoglycemic Agents; In Vitro Techniques; Piperidines; Solid Phase Microextraction; Tandem Mass Spectrometry

For point-of-care testing of the illegal fortification of repaglinide (Rep) in natural dietary supplements, a competitive chemiluminescent immunoassay (CLIA) was established, using a horseradish peroxidase (HRP)-luminol-H2O2 system for signal amplification. Polyclonal antibodies for Rep were produced via immunization technique. Following optimization of the enzyme reaction time and concentrations of antibody and coating antigen, the method showed a limit of quantification (LOQ) of 1.0 ng/mL in PBS and limit of detection (LOD) of 8.3 ng/mL in serum and 6.0 ng/mL in blank tablets. When applied in natural dietary supplements, the method provided results consistent with those from HPLC, suggesting that the proposed method could be used for rapid screening of Rep in natural dietary supplements and detecting Rep in serum after administration.

Topics: Carbamates; Chromatography, High Pressure Liquid; Dietary Supplements; Humans; Immunoassay; Limit of Detection; Luminescence; Piperidines; Point-of-Care Systems

Deposition of islet amyloid has been associated with beta-cell death, thereby furthering diabetes progression. Several hypoglycemic agents, such as thiazolidinediones, biguanide and dipeptidyl peptidase-4 inhibitors, have been known to preserve beta-cell mass, possibly by direct inhibition of islet amyloid formation. The general objective of this study was to evaluate the impact of the major representatives of hypoglycemic agents on amyloid formation by using in vitro molecular screening approaches.. Ten prototypical representatives of hypoglycemic agents were evaluated for the inhibition of amyloid formation in vitro using thioflavin fluorescence assays, far-ultraviolet circular dichroism, photo-induced cross linking assays and cell viability assays.. Glyburide, repaglinide and troglitazone showed the highest potency in delaying and reducing fibril formation. Troglitazone, a thiazolidinedione, was the most effective agent abrogating amyloid fibril formation. Troglitazone affected the secondary structures of incubated human islet amyloid polypeptide (hIAPP). The circular dichroism spectra showed a delayed transition to the beta sheet conformation. A photo-induced cross-linking-based oligomerization assay demonstrated that repaglinide supressed the formation of hIAPP oligomers, whereas glyburide and troglitazone were ineffective in inhibiting oligomerization. Cell toxicity induced by hIAPP was reduced by all 3 compounds.. This study provides new insights that could potentially identify new therapeutic strategies to impede the progression of pancreatic amyloidosis in human patients with type 2 diabetes.

Topics: Amyloid; Amyloidosis; Animals; Carbamates; Cell Survival; Chromans; Circular Dichroism; Glyburide; Humans; Hypoglycemic Agents; Insulin-Secreting Cells; Islet Amyloid Polypeptide; Piperidines; Protein Structure, Secondary; Rats; Thiazolidinediones; Troglitazone

1. Liver distribution and systemic exposure of pravastatin were the determinant factors of efficacy and toxicity of pravastatin. Aim of the present study was to investigate the effect of paroxetine on the liver distribution and systemic exposure of pravastatin in diabetic rats induced by combining high fat diet (HFD) and low-dose streptozotocin (STZ). 2. Plasma concentrations and liver distribution of pravastatin were measured in the presence of paroxetine. Effect of paroxetine on pravastatin excretion via bile, intestine, feces and urine, as well as pravastatin absorption via intestine was documented. Freshly isolated hepatocytes and Caco-2 cells were used to investigate the effect of paroxetine on pravastatin transport. 3. Paroxetine increased the systemic exposure of pravastatin and decreased hepatic distribution of pravastatin in diabetic rats. In vitro, paroxetine inhibited the hepatic uptake of pravastatin and promoted the efflux of pravastatin in freshly isolated hepatocytes, which may partly explain the decreased hepatic distribution of pravastatin by paroxetine. It was also observed that paroxetine promoted the absorption of pravastatin via jejunum and the uptake of pravastatin in Caco-2 cells. 4. We concluded that paroxetine increased the systemic exposure of pravastatin partly via promoting absorption via jejunum and inhibiting hepatic uptake of pravastatin.

Topics: Administration, Intravenous; Administration, Oral; Animals; Body Fluids; Carbamates; Cell Separation; Diabetes Mellitus, Experimental; Diet, High-Fat; Disease Models, Animal; Feces; Hepatocytes; Intestinal Absorption; Liver; Male; Paroxetine; Piperidines; Pravastatin; Rats, Sprague-Dawley; Tissue Distribution

The treatment of newly diagnosed type 2 diabetes mellitus is diverse, with no clear consensus regarding the initial drug regimen or dosing to achieve optimal glycemic control.. We treated 44 consecutive patients with newly diagnosed type 2 diabetes with maximally tolerated doses of pioglitazone 45 mg/day, metformin 1000-2000 mg/day, and repaglinide 1-4 mg before meals. The doses and drugs were subsequently decreased ("subtraction therapy") to achieve optimal glycemic control and minimize side effects. Three primary outcomes were measured: the short term HbA1c response, the long term HbA1c response, and the incidence of hypoglycemia.. All 44 patients responded with a rapid, progressive decline in their HbA1c levels from 11.43±2.3% to 6.17±0.72% (101±25.1 mmol/mol to 44±7.9 mmol/mol) by three months, and remained stable thereafter. An HbA1c ≤7.0% (≤53 mmol/mol) was reached within 1-4 months in 42 of 44 patients, and in every patient by 12 months. Each patient's lowest HbA1c level, 5.65±0.6% (38±6.6 mmol/mol), was reached over 6.3±2.9 months. Patients with initial HbA1c levels >10% (>86 mmol/mol) (n=33) responded similarly as those with HbA1c levels <10% (<86 mmol/mol) (n=11). Combination drug therapy maintained HbA1c levels between 5.0 and 7.0% (31 and 53 mmol/mol) for up to 14.83 years. Only one clinically significant hypoglycemic event occurred during 261.08 person-years of follow-up.. In our experience, combination drug "subtraction therapy" was safe and effective for treating all newly diagnosed type 2 diabetic patients.

Topics: Adult; Aged; Aged, 80 and over; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Follow-Up Studies; Glycated Hemoglobin; Goals; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Metformin; Middle Aged; Pioglitazone; Piperidines; Thiazolidinediones; Treatment Outcome

Repaglinide is an efficient anti-diabetic drug which is prescribed widely as multi-dosage oral daily regimens. Due to the low compliance inherent to each multi-dosage regimen, development of prolonged-release formulations could enhance the overall drug efficacy in patient populations.. Repaglinide-loaded solid lipid nanoparticles (SLNs) were developed and characterized in vitro. Various surfactants were used in this study during the nanocarrier preparation procedure and their corresponding effects on some physicochemical properties of SLNs such as size, zeta potential; drug loading parameters and drug release profiles was investigated. Stearic acid and glyceryl mono stearate (GMS) were used as lipid phase and phosphatidylcholin, Tween80, Pluronic F127, poly vinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) were used as surfactant/stabilizer.. The results showed some variations between formulations; where the Tween80-based SLNs showed smallest size, the phosphatidylcholin-based SLNs indicated most prolonged drug release time and the highest loading capacity. SEM images of these formulations showed morphological variations and also confirmed the nanoscale size of these particles. The FTIR and DSC results demonstrated no interaction between drug and excipients. The invitro release profiles of different formulations were studied and observed slow release of drug from all formulations. However significant differences were found among them in terms of their initial burst release as well as the whole drug release profile. From fitting these data to various statistical models, the Peppas model was proposed as the best model to describe the statistical indices and, therefore, mechanism of drug release.. The results of this study confirmed the effect of surfactant type on SLNs physicochemical properties such as morphological features, loading parameters, particle sizes and drug release kinetic. With respect to the outcome data, the mixture of phosphatidylcholin/Pluronic F127 was selected as the best surfactant/stabilizer to coat the lipid core comprising stearic acid and GMS.

Topics: Calorimetry, Differential Scanning; Carbamates; Delayed-Action Preparations; Drug Compounding; Drug Stability; Humans; Hypoglycemic Agents; Nanoparticles; Particle Size; Piperidines; Surface-Active Agents

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Drug Therapy, Combination; Exenatide; Fasting; Female; Glucagon-Like Peptide-1 Receptor; Humans; Hypoglycemic Agents; Insulin Glargine; Insulin, Long-Acting; Metformin; Middle Aged; Peptides; Piperidines; Pyrazines; Receptors, Glucagon; Sitagliptin Phosphate; Treatment Failure; Triazoles; Venoms

Interindividual variability in protein expression of organic anion-transporting polypeptides (OATPs) OATP1B1, OATP1B3, OATP2B1, and multidrug resistance-linked P-glycoprotein (P-gp) or ABCB1 was quantified in frozen human livers (n = 64) and cryopreserved human hepatocytes (n = 12) by a validated liquid chromatography tandem mass spectroscopy (LC-MS/MS) method. Membrane isolation, sample workup, and LC-MS/MS analyses were as described before by our laboratory. Briefly, total native membrane proteins, isolated from the liver tissue and cryopreserved hepatocytes, were trypsin digested and quantified by LC-MS/MS using signature peptide(s) unique to each transporter. The mean ± S.D. (maximum/minimum range in parentheses) protein expression (fmol/µg of membrane protein) in human liver tissue was OATP1B1- 2.0 ± 0.9 (7), OATP1B3- 1.1 ± 0.5 (8), OATP2B1- 1 1.7 ± 0.6 (5), and P-gp- 0.4 ± 0.2 (8). Transporter expression in the liver tissue was comparable to that in the cryopreserved hepatocytes. Most important is that livers with SLCO1B1 (encoding OATP1B1) haplotypes *14/*14 and *14/*1a [i.e., representing single nucleotide polymorphisms (SNPs), c.388A > G, and c.463C > A] had significantly higher (P < 0.0001) protein expression than the reference haplotype (*1a/*1a). Based on these genotype-dependent protein expression data, we predicted (using Simcyp) an up to ∼40% decrease in the mean area under the curve of rosuvastatin or repaglinide in subjects harboring these variant alleles compared with those harboring the reference alleles. SLCO1B3 (encoding OATP1B3) SNPs did not significantly affect protein expression. Age and sex were not associated with transporter protein expression. These data will facilitate the prediction of population-based human transporter-mediated drug disposition, drug-drug interactions, and interindividual variability through physiologically based pharmacokinetic modeling.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Alleles; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Carbamates; Child; Child, Preschool; Chromatography, Liquid; Female; Fluorobenzenes; Haplotypes; Hepatocytes; Humans; Individuality; Infant; Liver; Male; Middle Aged; Organic Anion Transporters; Piperidines; Polymorphism, Single Nucleotide; Pyrimidines; Rosuvastatin Calcium; Sulfonamides; Tandem Mass Spectrometry; Young Adult

Rosuvastatine, doxazosin, repaglinide and oxcarbazepin are therapeutic drugs available in the market for the treatment of different diseases. Potential to display antitumor activities has also been suggested. The aim of the current study was to evaluate their in vitro effects on some human transformed cell lines.. Cytotoxicity of the four drugs was tested in MCF-7, HeLa and HepG2 cells by the neutral red assay method and also the effect of rosuvastatine and doxazosin against Ehrlich Ascities Carcinoma Cells (EACC) by trypan blue assay.. Rosuvastatine exerted the greatest cytotoxic effect against HepG2 cells with an IC50 value of 58.7±69.3; in contrast doxazosin showed least activity with IC50=104.4 ±115.7. Repaglinide inhibited the growth of both HepG2 and HeLa cells with IC50 values of 87.6±117.5 and 89.3±119.5, respectively. Oxcarbazepine showed a potent cytotoxicity against both HeLa (IC50=19.4±43.9) and MCF7 cancer cells ((IC50=22±35.7).On the other hand the growth of EACC was completely inhibited by doxazosine (100% inhibition) while rosuvastatine had weak inhibitory activity (11.6%) .. The four tested drugs may have cytotoxic effects against hepatic, breast and cervical carcinoma cells; also doxazosine may inhibit the growth of endometrial cancer cells. Further investigations in animals are needed to confirm these results.

Topics: Animals; Anticonvulsants; Antihypertensive Agents; Antineoplastic Agents; Carbamates; Carbamazepine; Carcinoma, Ehrlich Tumor; Cell Proliferation; Cell Survival; Doxazosin; Fluorobenzenes; HeLa Cells; Hep G2 Cells; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoglycemic Agents; Inhibitory Concentration 50; MCF-7 Cells; Oxcarbazepine; Piperidines; Pyrimidines; Rosuvastatin Calcium; Sulfonamides

The marketed compound tablet of metformin hydrochloride (MH) and repaglinide (RG) exhibits perfect multidrug therapeutic effect of type 2 diabetes. However, due to the short half life of the drugs, the tablet has to be administered 2 to 3 times a day, causing inconvenience to patient and fluctuations of plasma concentration. Here, a sandwiched osmotic pump tablet was developed to deliver the two drugs simultaneously at zero-order rate, in which MH and RG were loaded in different layers separated by a push layer. The osmotic pump tablet was prepared by a combination of three tableting procedure and film coating method. The factors including type and amount of propellant, osmotic active agents, amount of porogenic agent, coating weight, orifice diameter were optimized. The pharmacokinetic study was performed in beagle dogs, and the drug concentration in plasma samples was assayed by HPLC-MS/MS method. Simultaneous, controlled release of MH and RG in the first 12 and 8h was achieved from the optimized formulation. A significantly decreased Cmax, prolonged Tmax and satisfactory bioavailability of the osmotic pump tablet were obtained, and a good in vivo-in vitro correlation of the two drugs was also established. In summary, the sandwiched osmotic pump tablet released the MH and RG simultaneously at zero-order rate, and exhibited significant sustained release effect in vivo and good in vivo-in vitro correlation. The designed controlled release system for MH and RG proposed a promising replacement for the marked compound product in the therapy of type 2 diabetes.

Topics: Animals; Carbamates; Delayed-Action Preparations; Dogs; Drug Combinations; Hypoglycemic Agents; Male; Metformin; Osmosis; Piperidines; Tablets

To investigate the effect of OATP1B1 genotype as a covariate on repaglinide pharmacokinetics and drug-drug interaction (DDIs) risk using a reduced physiologically-based pharmacokinetic (PBPK) model.. Twenty nine mean plasma concentration-time profiles for SLCO1B1 c.521T>C were used to estimate hepatic uptake clearance (CLuptake) in different genotype groups applying a population approach in NONMEM v.7.2.. Estimated repaglinide CLuptake corresponded to 217 and 113 μL/min/10(6) cells for SLCO1B1 c.521TT/TC and CC, respectively. A significant effect of OATP1B1 genotype was seen on CLuptake (48% reduction for CC relative to wild type). Sensitivity analysis highlighted the impact of CLmet and CLdiff uncertainty on the CLuptake optimization using plasma data. Propagation of this uncertainty had a marginal effect on the prediction of repaglinide OATP1B1-mediated DDI with cyclosporine; however, sensitivity of the predicted magnitude of repaglinide metabolic DDI was high. In addition, the reduced PBPK model was used to assess the effect of both CYP2C8*3 and SLCO1B1 c.521T>C on repaglinide exposure by simulations; power calculations were performed to guide prospective DDI and pharmacogenetic studies.. The application of reduced PBPK model for parameter optimization and limitations of this process associated with the use of plasma rather than tissue profiles are illustrated.

Topics: Carbamates; Computer Simulation; Cytochrome P-450 CYP2C8; Drug Interactions; Genotype; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Models, Biological; Monte Carlo Method; Organic Anion Transporters; Piperidines; Polymorphism, Genetic; Prospective Studies

Repaglinide, an oral antidiabetic agent, has a rapid onset of action and short half-life of approximately 1 h. Designing a controlled release dosage form of the drug is required to maintain its therapeutic blood level and to eliminate its adverse effects, particularly the hypoglycaemia. Repaglinide sustained release matrix pellets consisting of Avicel, lactose and different polymers were prepared using extrusion-spheronisation method. The effect of different formulation components on in vitro drug release were evaluated using USP apparatus (paddle) for 12 h in phosphate buffer. The optimised formulation was orally administrated to normal and STZ induced diabetic rats. Most pellet formulations had acceptable physical properties with regard to size distribution, flowability and friability. Repaglinide pellets comprising Avicel 50%, lactose 47% and SLS 1% were released 94% of its drug content after 12 h. The optimised formulation was able to decrease blood glucose level in normal rats and those with diabetes throughout 8-12 h.

Topics: Administration, Oral; Animals; Blood Glucose; Carbamates; Cellulose; Diabetes Mellitus, Experimental; Drug Evaluation, Preclinical; Drug Implants; Hypoglycemic Agents; Lactose; Male; Piperidines; Rats; Rats, Wistar

Meglitinides (nateglinide and repaglinide) are widely used oral drugs for the treatment of type II diabetes mellitus. In the present study, the effects of meglinitides administered supraspinally on kainic acid (KA)-induced hippocampal neuronal cell death and hyperglycemia were studied in ICR mice. Mice were pretreated intracerebroventricularly (i.c.v.) with 30 μg of nateglinide and repaglinide for 10 min and then, mice were administered i.c.v. with KA (0.1 μg). The neuronal cell death in the CA3 region in the hippocampus was assessed 24h after KA administration and the blood glucose level was measured 30, 60, and 120 min after KA administration. We found that i.c.v. pretreatment with repaglinide attenuated the KA-induced neuronal cell death in CA3 region of the hippocampus and hyperglycemia. However, nateglinide pretreated i.c.v. did not affect the KA-induced neuronal cell death and hyperglycemia. In addition, KA administered i.c.v. caused an elevation of plasma corticosterone level and a reduction of the plasma insulin level. Furthermore, i.c.v. pretreatment with repaglinide attenuated KA-induced up-regulation of plasma corticosterone level. Furthermore, i.c.v. administration of repaglinide alone increased plasma insulin level and repaglinide pretreated i.c.v. caused a reversal of KA-induced hypoinsulinemic effect. Our results suggest that supraspinally administered repaglinide, but not nateglinide, exerts a protective effect against the KA-induced neuronal cells death in CA3 region of the hippocampus. The neuroprotective effect of repaglinide appears to be mediated by lowering the blood glucose level induced by KA.

Topics: Animals; Blood Glucose; CA3 Region, Hippocampal; Carbamates; Cell Death; Corticosterone; Cyclohexanes; Excitatory Amino Acid Agonists; Hypoglycemic Agents; Infusions, Intraventricular; Insulin; Kainic Acid; Male; Mice; Mice, Inbred ICR; Nateglinide; Neurons; Phenylalanine; Piperidines

The aim of the present study was to load the post-prandial glucose regulator, repaglinide (REP), on spray dried mucoadhesive microparticles (MPs) comprising anionic polysaccharides. The formulation parameters of the polysaccharides-REP spray dried powders (SDP) namely, polysaccharide type and drug to polymer (D/P) ratio, were optimized for % release after 5 min (R%5 min) and time required for 80% release (T80%). The suitability of the selected formulae for nasal application was evaluated by ex vivo mucoadhesion, in vitro cytocompatability and tolerability studies. A pharmacodynamic study in diabetic rats was conducted. Results showed that both polysaccharide type and amount greatly influenced the chosen responses. REP was highly incorporated in mucoadhesive MPs with proven safety on the rat nasal mucosa. The selected REP loaded powders exhibited a significant two to threefold increase in total decrease in blood glucose compared to the nasal and intravenous solutions.

Topics: Administration, Intranasal; Animals; Blood Glucose; Carbamates; Diabetes Mellitus, Experimental; Drug Delivery Systems; Hypoglycemic Agents; Male; Nasal Mucosa; Piperidines; Rats

To develop a capillary electrophoresis system for enantiomeric impurity test of repaglinide.. An uncoated fused silica capillary (50 μm×50 cm, with an effective length of 41 cm) was used. The running buffer was composed of 30 mmol/L NaH2PO4 and 5 mg/ml carboxymethyl-β-cyclodextrin(pH 3.5).. Linear range was 2.00-80.00 μg/ml (correlation coefficient was 0.9993). The average recovery rate was 92.5% to 105.0%.. The method is simple, accurate and sensitive and it can be used for determination of enantiomeric impurities in repaglinide tablet.

Topics: Carbamates; Electrophoresis, Capillary; Piperidines; Stereoisomerism; Tablets

The study aims to establish a method for simultaneous determination of repaglinide and pravastatin sodium in rat plasma by LC-MS/MS and to study its pharmacokinetic interactions. Eighteen male SD rats were divided into repaglinide group, pravastatin sodium group and co-administration group. Blood samples were collected at different times after oral administration. Repaglinide and pravastatin sodium in rat plasma were separated by Agilent HC-C18 with the mobile phase consisting of methanol-0.1% formic acid (80 : 20). Detection and quantification were performed by using ESI-MS. The detector was operated in selected Reaction-monitoring mode at m/z 453.3-->230.1 for repaglinide, m/z 447.2-->327.4 for pravastatin sodium and m/z 285.1-->192.9 for diazepam as the internal standard. The calibration curve obtained was linear (R2>0.99) over the concentration range of 9.77-10,000 ng.mL-1 for repaglinide and 4.88-625 ng.mL-1 for pravastatin sodium. Compared with the single administration group, Cmax and AUC0-6h of repaglinide increased significantly (P<0.05) and tmax of pravastatin sodium prolonged (P<0.05) in co-administration group. The method is found to be simple, sensitive and accurate for determining the concentration of repaglinide and pravastatin sodium in rat plasma. There exists pharmacokinetic interactions in the co-administration of repaglinide and pravastatin sodium.

Topics: Administration, Oral; Animals; Carbamates; Chromatography, High Pressure Liquid; Drug Interactions; Male; Piperidines; Pravastatin; Random Allocation; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

Interpenetrated polymer network (IPN) microparticles of sterculia gum and sodium alginate loaded with repaglinide were developed by ionic gelation and emulsion crosslinking method. The drug entrapment efficiency was as high as 91%. FTIR and TG analyses confirmed the crosslinking and IPN formation. Microparticles have demonstrated the drug release up to 24h depending upon type of crosslinking agents; the glutaraldehyde treatment of ionically crosslinked microparticles has resulted in decreased drug release rate. The in-vivo anti-diabetic activity performed on streptozotocin induced diabetic rats indicated that the pristine repaglinide has shown maximum percentage reduction of elevated blood glucose within 3h and then the percentage reduction in blood glucose was decreased. In the case of rats treated with KA8 IPN microparticles, percentage reduction of elevated glucose was slow as compared to pristine drug within 3h, but it was gradually increased to 81.27% up to 24h.

Topics: Alginates; Animals; Carbamates; Delayed-Action Preparations; Drug Carriers; Glucuronic Acid; Hexuronic Acids; Hypoglycemic Agents; Microspheres; Pancreas; Particle Size; Piperidines; Plant Gums; Polymers; Rats; Rats, Wistar; Sterculia

The aim of the present work was to test the ability of two non-diabetogenic carbohydrates to intranasally deliver the insulinotropic drug repaglinide (REP) for controlling blood glucose level. REP was loaded onto chitosan/alginate nanocomplexes (NCs) suitable for mucosal delivery and uptake. Improved stability and delivery characteristics were obtained by spray drying the selected NCs, yielding microparticles. A statistical experimental design was adopted to investigate the effects of the formulations' variables on two critical responses: NC size and drug entrapment efficiency. Physicochemical characterizations of the network's structures were done, and in vitro cytotoxicity and histopathological studies were conducted. The potential of the developed system to prolong the drug effect was tested on diabetic rats. The results showed that to attain particles suitable for nasal delivery, alginate should be used at its lowest level used in this study (0.6 mg/mL). A low level of chitosan (0.5 mg/mL) was needed when the drug was cation-loaded, while the high chitosan level (1 mg/mL) was more suitable when REP was anion-loaded. The best entrapment efficiency was achieved at a theoretical drug loading of 0.025 mg/mL. Discrete NCs could be rapidly recovered from the spray-dried microparticles. The cytotoxicity and histopathological studies indicated that such formulations were well tolerated. The antihyperglycemic activity of the nasally administered formulae was gradual but was significantly sustained over 24 hours, suggesting NC mucosal uptake. Nasal delivery of such dry powders achieved better glycemic control compared with the conventional oral tablets.

Topics: Administration, Intranasal; Animals; Blood Glucose; Carbamates; Cell Line; Cell Survival; Chemistry, Pharmaceutical; Diabetes Mellitus, Experimental; Drug Carriers; Hypoglycemic Agents; Male; Microspheres; Nasal Mucosa; Piperidines; Rats, Wistar

The therapeutic efficacy of repaglinide (RPG) is limited by the low and variable oral bioavailability owing to its limited aqueous solubility. In our present study, the development and evaluation of inclusion complex applying hydroxypropyl-β-cyclodextrin (HP-β-CD) for the improvement of oral bioavailability of repaglinide was investigated systematically. The inclusion complex of repaglinide was prepared by lyophilization technique using drug: hydroxypropyl-β-cyclodextrin (1:15 mole). The prepared complexation was characterized by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), NMR spectroscopy and evaluated by dissolution studies. The (1)H NMR was used in the structure study of repaglinide-HP-β-CD (RPG-HP-β-CD) inclusion complex. The analysis proved the higher probability of the repaglinide A-ring into the narrow rim of the β-cyclodextrin molecule. All the characterization information confirmed the formation of RPG-HP-β-CD inclusion complex. The in vivo pharmacokinetics of RPG-HP-β-CD and their physical mixture were performed in beagle dogs. For the first time, a simple, rapid, and sensitive LC-MS/MS method for determination of RPG in beagle dog plasma was developed. The Cmax and AUC0-t of RPG-HP-β-CD were 2.5 and 2 times higher than that of the physical mixture. These results suggested that the interaction of repaglinide with HP-β-CD could notably improve the dissolution rate and bioavailability of repaglinide comparing with its physical mixture.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Animals; Area Under Curve; beta-Cyclodextrins; Biological Availability; Calorimetry, Differential Scanning; Carbamates; Chemistry, Pharmaceutical; Chromatography, Liquid; Dogs; Freeze Drying; Hypoglycemic Agents; Magnetic Resonance Spectroscopy; Piperidines; Solubility; Tandem Mass Spectrometry; X-Ray Diffraction

Topics: Aged, 80 and over; Carbamates; Diabetes Mellitus, Type 2; Frail Elderly; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Piperidines

Type 2 diabetes is characterised by insulin resistance and deficiencywhich explains the multitude of molecules developed for its treatment.The beneficial effects of metformin and sulfamides have been demonstrated. Over the last 10 years, new molecules have appeared: acarbose, repaglinide and incretins.

Topics: Carbamates; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Drug Therapy, Combination; Glucagon-Like Peptide 1; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Incretins; Piperidines

Topics: Aged; Carbamates; Diabetes Mellitus, Type 2; Humans; Male; Piperidines; Thrombocytopenia

CYP2C8 plays an important role in the metabolism of various drugs, such as paclitaxel, repaglinide and ibuprofen. Polymorphisms in the CYP2C8 gene were shown to influence interindividual differences in the pharmacokinetics of paclitaxel, repaglinide and ibuprofen enantiomers. In this study, three CYP2C8 allelic variants (CYP2C8.2, CYP2C8.3 and CYP2C8.4) and wild-type CYP2C8 (CYP2C8.1) were co-expressed for the first time with human cytochrome P450 oxidoreductase (POR) and cytochrome b5 by using a baculovirus-assisted insect cell expression system. Further, the effects of genotype-phenotype correlations of CYP2C8 alleles on the metabolism of paclitaxel, repaglinide and ibuprofen enantiomers were evaluated. The CLint values of CYP2C8.2, CYP2C8.3 and CYP2C8.4 for paclitaxel were 47.7%, 64.3% and 30.2% of that of CYP2C8.1 (p<0.01). The CLint values of CYP2C8.2 and CYP2C8.4 for repaglinide were 77.9% and 80.2% of that of CYP2C8.1 (p<0.05), respectively, while the CLint value of CYP2C8.3 was 1.31-fold higher than that of CYP2C8.1 (p<0.05). The relative CLint values of CYP2C8.2, CYP2C8.3 and CYP2C8.4 were 110.5%, 72.3% and 49.7% of that of CYP2C8.1 and were 124.6%, 83.4% and 47.4% of that of CYP2C8.1 for R-ibuprofen and S-ibuprofen, respectively. Comparing hydroxylation by CYP2C8.1 and CYP2C8.3 resulted in higher and lower intrinsic clearance of repaglinide and ibuprofen enantiomers, respectively. These in vitro findings were consistent with the pharmacokinetics in volunteers who were heterozygous or homozygous carriers of CYP2C8*3. The results of this study provide useful information for predicting CYP2C8 phenotypes and may contribute to individualized drug therapy in the future.

Topics: Antineoplastic Agents, Phytogenic; Aryl Hydrocarbon Hydroxylases; Baculoviridae; Carbamates; Cyclooxygenase Inhibitors; Cytochrome P-450 CYP2C8; Cytochromes b5; Genetic Vectors; Genome-Wide Association Study; Humans; Hydroxylation; Hypoglycemic Agents; Ibuprofen; Liver; Paclitaxel; Piperidines; Polymorphism, Genetic

Recently, coamorphous systems composed of two drugs or a drug and a small molecule excipient, gained interests due to their ability in overcoming limitations associated with solid dispersions. In this study, coamorphous form of repaglinide (REP), a BCS class II anti-diabetic drug with low aqueous solubility and high permeability was achieved with saccharin (SAC) by solution crystallization and characterized. An accurate and precise HPLC method was established for the simultaneous determination of REP and SAC. Coamorphous REP-SAC with 1:1 stoichiometry had unique thermal behavior, obvious FTIR shifts and the absence of sharp diffraction peak, suggesting the formation of a coamorphous material and interaction of REP with SAC through hydrogen bonds formed between REP's secondary amine and SAC's carbonyl group. Coamorphous REP-SAC showed great improvement in solubility and dissolution under sink conditions in various media. In addition, it was conformed in supersaturated dissolution of coamorphous REP-SAC in distilled water that the coamorphous material had remarkably longer time length for REP to be remained at a supersaturated concentration and had better metastable solubility. This coamorphous system provides a feasible way to process drugs with low solubility into substances with enhanced dissolution and stabilized amorphous state that could be conducive to greater bioavailability than the crystalline drug.

Topics: Calorimetry, Differential Scanning; Carbamates; Chemistry, Pharmaceutical; Crystallization; Hypoglycemic Agents; Piperidines; Powder Diffraction; Saccharin; Solubility; Spectroscopy, Fourier Transform Infrared; X-Ray Diffraction

A change in the function or expression of hepatic drug transporters may have significant effect on the efficacy or safety of orally administered drugs. Although a number of clinical drug-drug interactions associated with hepatic transport proteins have been reported, in practice it is not always straightforward to discriminate other pathways (e.g. drug metabolism) from being involved in these interactions. The present study was designed to assess the interactions between organic anion transporting polypeptide (Oatp) substrates (pravastatin or repaglinide) and inhibitors (spironolactone or diphenhydramine) in vivo in rats. The mechanisms behind the interactions were then investigated using in vitro tools (isolated hepatocytes and rat liver microsomes). The results showed a significant increase in the systemic exposures of pravastatin (2.5-fold increase in AUC) and repaglinide (1.8-fold increase in AUC) after co-administration of spironolactone to rats. Diphenhydramine increased the AUC of repaglinide by 1.4-fold. The in vivo interactions observed in rats between Oatp substrates and inhibitors may a priori be classified as transport-mediated drug-drug interactions. However, mechanistic studies performed in vitro using both isolated rat hepatocytes and rat liver microsomes showed that the interaction between pravastatin and spironolactone may be solely linked to the inhibition of pravastatin uptake in liver. On the contrary, the inhibition of cytochrome P450 seemed to be the reason for the interactions observed between repaglinide and spironolactone. Although the function and structure of transport proteins may vary between rats and humans, the approach used in the present study can be applied to humans and help to understand the role of drug transport and drug metabolism in a given drug-drug interaction. This is important to predict and mitigate the risk of drug-drug interactions for a candidate drug in pre-clinical development, it is also important for the optimal design of drug-drug interactions studies in the clinic.

Topics: Animals; Carbamates; Cells, Cultured; Diphenhydramine; Drug Interactions; Hepatocytes; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoglycemic Agents; Male; Microsomes, Liver; Organic Anion Transporters; Piperidines; Pravastatin; Rats; Rats, Sprague-Dawley; Spironolactone

The aim of study was to develop self-nanoemulsifying pellets (SNEP) for oral delivery of poorly water soluble drug, repaglinide (RPG). Solubility of RPG in oily phases and surfactants was determined to identify components of self-nanoemulsifying drug delivery system (SNEDDS). The surfactants and cosurfactants were screened for their ability to emulsify oily phase. Ternary phase diagrams were constructed to identify nanoemulsification area for the selected systems. SNEDDS formulations with globule size less than 100 nm were evaluated for in vivo anti-hyperglycemic activity in neonatal streptozotocin rat model. A significant reduction in glucose levels was produced by optimized SNEDDS formulation in comparison to the control group. The optimized SNEDDS formulations were pelletized via extrusion/spheronization technique using microcrystalline cellulose and lactose. SNEP were characterized by X-ray powder diffraction and scanning electron microscopy. X-ray diffraction study indicated loss of crystallinity of RPG in SNEP. The SNEP exhibited good flow properties, mechanical strength and formed nanoemulsion with globule size less than 200 nm. SNEP showed in vitro release of more than 80% RPG in 10 min which was significantly higher than RPG containing reference pellets. In conclusion, our studies illustrated that RPG, a poorly water soluble drug can be successfully formulated into SNEP which can serve as a promising system for the delivery of poorly water soluble drugs.

Topics: Animals; Carbamates; Chromatography, High Pressure Liquid; Drug Design; Emulsions; Hydrogen-Ion Concentration; Hypoglycemic Agents; Microscopy, Electron, Scanning; Nanostructures; Piperidines; Powder Diffraction; Rats; Solubility; Surface-Active Agents

Biodegradable polymeric nanoparticles loaded Repaglinide were prepared by solvent extraction method. In this method chitosan, PLA and PCL were employed to prepare Repaglinide polymeric nanoparticles. Some of the formulation parameters were optimized to obtain high quality nanoparticles. The particles were spherical shape with sizes of 108.6 ± 3.4 nm to 220.6 ± 1.2 nm and the poly dispersity indexes were in the range of 0.06 to 0.44. The zeta potential was in the range between - 16.48 ± 2.02 and 30.52 ± 3.20 mV. The percentage entrapment efficiency (EE%) was 81.4 ± 1.8% to 92.7 ± 1.4%. The drug release behavior was studied by externally sink method and the release pattern of drug was found to follow zero order, Higuchi and Peppas equations. The optimized PLA-Repaglinide nanoparticles were loaded in Methocel transdermal patches. These transdermal patches were evaluated by physiochemical parameters, in vitro, ex vivo and in vivo studies. Based on in vivo hypoglycemic results, bioavailability parameters like AUC, AUMC, Cmax, Tmax, MRT, t1/2 and relative bioavailability were found to be 2218.88 μIU/mL/h, 381630.3 μIU/mL/h, 41.88 μIU/mL, 36 h, 83.24h, and 52.79 h respectively. The transdermal patch containing Repaglinide nanoparticles showed 76 fold effective than conventional oral administrations.

Topics: Animals; Biocompatible Materials; Biological Availability; Blood Glucose; Carbamates; In Vitro Techniques; Insulin; Kinetics; Lactic Acid; Nanoparticles; Particle Size; Permeability; Piperidines; Polyesters; Polymers; Rats, Wistar; Skin Absorption; Spectroscopy, Fourier Transform Infrared; Transdermal Patch

The full factorial design was employed to evaluate contribution of drug: polymer and Eudragit RS 100: Eudragit RL 100 on entrapment efficiency, time for maximum drug release, percentage of drug release. Floating microparticles were prepared using spray drying technique. Microparticles were evaluated for buoyancy and drug release study using paddle type dissolution apparatus using pH 1.2 buffer as dissolution medium. All the formulations showed good buoyancy with more than 90% microparticles floating for 12hrs. It was found that amount of polymer affected entrapment efficiency (P<0.05). Eudragit RS 100: Eudragit RL100 affected time for maximum drug release (P<0.05). The diffusion coefficient (n) value of the optimized formula was found to be 0.7042 which indicates mechanism of release is anomalous transport. Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry studies showed that drug and excipients are compatible. Size of the microparticles ranged from 21-30 μM. Scanning electron microscopy showed that microparticles are spherical and non-aggregated. In this study it was found that spray drying can be used to produce floating microparticles successfully without use of solvents like dichloromethane, which is a class II solvent or aromatic solvents like ethyl acetate.

Topics: Calorimetry, Differential Scanning; Carbamates; Chemistry, Pharmaceutical; Drug Delivery Systems; Particle Size; Piperidines; Polymers; Solubility; Spectroscopy, Fourier Transform Infrared; Technology, Pharmaceutical

Topics: Carbamates; Clinical Trials as Topic; Humans; Hypoglycemic Agents; Mortality; Piperidines; Sulfonylurea Compounds

A simple, sensitive, selective, and reproducible liquid chromatography-tandem mass spectrometric method was developed for the simultaneous determination of repaglinide and metformin in human plasma using d5-repaglinide and d6-metformin as internal standards (ISs). After a simple protein precipitation using acetonitrile as the precipitation solvent, both analytes and ISs were separated on a Venusil ASB C 18 (150 mm x 4.6 mm, 5 microm) via gradient elution using acetonitrile--10 mmol x L(-1) ammonium acetate as the mobile phase. A chromatographic total run time of 7.5 min was achieved. Mass spectrometric detection was conducted with atmospheric pressure chemical ionization under positive-ion and multiple-reaction monitoring modes. The method was linear over the 0.2 to 60.0 ng x mL(-1) concentration range for repaglinide and over the 4 to 1 000 ng x mL(-1) range for metformin. For both analytes, the intra- and inter-accuracies and precisions were within the +/- 15% acceptable limit across all concentrations. The validated method was successfully applied to a clinical bioequivalence study.

Topics: Administration, Oral; Adolescent; Adult; Area Under Curve; Carbamates; Chromatography, Liquid; Drug Stability; Female; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Piperidines; Tandem Mass Spectrometry; Therapeutic Equivalency; Young Adult

Interactions between conventional drug and traditional medicine therapies may potentially affect drug efficacy and increase the potential for adverse reactions. Cree traditional healing is holistic and patients may use medicinal plants simultaneously with the conventional drugs. However, there is limited information that these medicinal plants may interact with drugs and additional mechanistic information is required. In this study, extracts from traditionally used Cree botanicals were assessed for their potential interaction that could alter the disposition of two blood glucose lowering drugs, gliclazide (Diamicron) and repaglinide (Gluconorm) though inhibition of either metabolism or transport across cell membranes.. The effect of 17 extracts on metabolism was examined in a human liver microsome assay by HPLC and individual cytochrome P450s 2C9, 2C19, 2C8 and 3A4 in a microplate fluorometric assay. Gliclazide, rhaponticin and its aglycone derivative, rhapontigenin were also examined in the fluorometric assay. The effect on transport was examined with 11 extracts using the intestinal epithelial Caco-2 differentiated cell monolayer model at times up to 180 min.. Both blood glucose lowering medications, gliclazide and repaglinide traversed the Caco-2 monolayer in a time-dependent manner that was not affected by the Cree plant extracts. Incubation of the Cree plant extracts inhibited CYP2C9, 2C19, 2C8 and 3A4-mediated metabolism, and the formation of four repaglinide metabolites: M4, m/z 451-A, m/z 451-B and the glucuronide of repaglinide in the human liver microsome assay. Gliclazide caused no significant inhibition. Likewise, rhaponticin had little effect on the enzymes causing changes of less than 10% with an exception of 17% inhibition of CYP2C19. By contrast, the aglycone rhapontigenin showed the greatest effects on all CYP-mediated metabolism. Its inhibition ranged from a mean of 58% CYP3A4 inhibition to 89% inhibition of CYP2C9. While rhaponticin and the aglycone did not show significant effects on repaglinide metabolism, they demonstrated inhibition of gliclazide metabolism. The aglycone significantly affected levels of gliclazide and its metabolites.. These studies demonstrate that the Cree plant extracts examined have the potential in vitro to cause drug interactions through effects on key metabolic enzymes.

Topics: Aryl Hydrocarbon Hydroxylases; Caco-2 Cells; Carbamates; Drug Interactions; Gliclazide; Glucuronosyltransferase; Humans; Hypoglycemic Agents; Intestinal Absorption; Medicine, Traditional; Microsomes, Liver; Piperidines; Plant Extracts; Plants, Medicinal; Quebec; Stilbenes

The aim of this study was to investigate the effects of nifedipine on the bioavailability and pharmacokinetics of repaglinide in rats.. The effect of nifedipine on P-glycoprotein (P-gp) and cytochrome P450 (CYP) 3A4 activity was evaluated. The pharmacokinetic parameters of repaglinide and blood glucose concentrations were also determined in rats after oral (0.5 mg/kg) and intravenous (0.2 mg/kg) administration of repaglinide to rats in the presence and absence of nifedipine (1 and 3 mg/kg).. Administration of nifedipine resulted in inhibition CYP3A4 activity with an IC50 value of 7.8 μM, and nifedipine significantly inhibited P-gp activity in a concentration-dependent manner. Compared to the oral control group, nifedipine significantly increased the area under the plasma concentration-time curve (AUC0-∞) and the peak plasma concentration (Cmax) of repaglinide by 49.3 and 25.5%, respectively. Nifedipine significantly decreased the total body clearance (CL/F) of repaglinide by 22.0% compared to the oral control group. Nifedipine also increased the absolute bioavailability (AB) of repaglinide by 50.0% compared to the oral control group (33.6%). In addition, the relative bioavailability (RB) of repaglinide was 1.16- to 1.49-fold greater than that of the control group. Compared to the intravenous control, nifedipine significantly increased AUC0-∞ of repaglinide. Blood glucose concentrations had significant differences compared to the oral control groups.. Nifedipine enhanced the oral bioavailability of repaglinide, which may be mainly attributable to inhibition of CYP3A4-mediated metabolism of repaglinide in the small intestine and/or in the liver and to inhibition of the P-gp efflux transporter in the small intestine and/or reduction of total body clearance by nifedipine. The current study has raised awareness of potential drug interactions by concomitant use of repaglinide with nifedipine.

Topics: Administration, Oral; Animals; Area Under Curve; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Availability; Biomarkers; Biotransformation; Blood Glucose; Calcium Channel Blockers; Carbamates; Cytochrome P-450 CYP3A; Cytochrome P-450 CYP3A Inhibitors; Dose-Response Relationship, Drug; Drug Interactions; Enzyme Inhibitors; Humans; Hypoglycemic Agents; Injections, Intravenous; Male; Nifedipine; Piperidines; Polypharmacy; Rats; Rats, Sprague-Dawley

A highly sensitive and specific LC-MS/MS-ESI method has been developed for simultaneous quantification of metformin (MFN) and repaglinide (RGN) in rat plasma (50 μL) using phenacetin as an internal standard (IS). Simple protein precipitation was used to extract MFN and RGN from rat plasma. The chromatographic resolution of MFN, RGN and IS was achieved with a mobile phase consisting of 0.2% formic acid in water-acetonitrile (1:1, v/v) with a time program flow gradient on a Chromolith RP-18e column. The total chromatographic run time was 3.5 min and the elution of MFN, RGN and IS occurred at 1.64, 2.21 and 2.15 min, respectively. A linear response function was established for the range of concentrations 0.855-394 and 0.021-21.7 ng/mL for MFN and RGN, respectively. The intra- and inter-day precision values for MFN and RGN met the acceptance as per FDA guidelines. MFN and RGN were stable in battery of stability studies viz., bench-top, auto-sampler and freeze-thaw cycles. The developed assay was applied to a pharmacokinetic study in rats.

Topics: Animals; Carbamates; Chromatography, Liquid; Drug Stability; Linear Models; Male; Metformin; Piperidines; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

The plasma concentration of repaglinide is reported to increase greatly when given after repeated oral administration of itraconazole and gemfibrozil. The present study analyzed this interaction based on a physiologically based pharmacokinetic (PBPK) model incorporating inhibition of the hepatic uptake transporter and metabolic enzymes involved in repaglinide disposition. Firstly, the plasma concentration profiles of inhibitors (itraconazole, gemfibrozil, and gemfibrozil glucuronide) were reproduced by a PBPK model to obtain their pharmacokinetic parameters. The plasma concentration profiles of repaglinide were then analyzed by a PBPK model, together with those of the inhibitors, assuming a competitive inhibition of CYP3A4 by itraconazole, mechanism-based inhibition of CYP2C8 by gemfibrozil glucuronide, and inhibition of organic anion transporting polypeptide (OATP) 1B1 by gemfibrozil and its glucuronide. The plasma concentration profiles of repaglinide were well reproduced by the PBPK model based on the above assumptions, and the optimized values for the inhibition constants (0.0676 nM for itraconazole against CYP3A4; 14.2 μM for gemfibrozil against OATP1B1; and 5.48 μM for gemfibrozil glucuronide against OATP1B1) and the fraction of repaglinide metabolized by CYP2C8 (0.801) were consistent with the reported values. The validity of the obtained parameters was further confirmed by sensitivity analyses and by reproducing the repaglinide concentration increase produced by concomitant gemfibrozil administration at various timings/doses. The present findings suggested that the reported concentration increase of repaglinide, suggestive of synergistic effects of the coadministered inhibitors, can be quantitatively explained by the simultaneous inhibition of the multiple clearance pathways of repaglinide.

Topics: Area Under Curve; Aryl Hydrocarbon Hydroxylases; Biotransformation; Carbamates; Computer Simulation; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 CYP3A Inhibitors; Drug Interactions; Enzyme Inhibitors; Gemfibrozil; Glucuronides; Humans; Hypoglycemic Agents; Itraconazole; Least-Squares Analysis; Liver; Liver-Specific Organic Anion Transporter 1; Models, Biological; Nonlinear Dynamics; Organic Anion Transporters; Piperidines

To assess the effect of two hypoglycemic drugs on ischemic preconditioning (IPC) patients with type 2 diabetes and coronary artery disease (CAD).. We performed a prospective study of 96 consecutive patients allocated into two groups: 42 to group repaglinide (R) and 54 to group vildagliptin (V). All patients underwent two consecutive exercise tests (ET1 and ET2) in phase 1 without drugs. In phase 2, 1 day after ET1 and -2, 2 mg repaglinide three times daily or 50 mg vildagliptin twice daily was given orally to patients in the respective group for 6 days. On the seventh day, 60 min after 6 mg repaglinide or 100 mg vildagliptin, all patients underwent two consecutive exercise tests (ET3 and ET4).. In phase 1, IPC was demonstrated by improvement in the time to 1.0 mm ST-segment depression and rate pressure product (RPP). All patients developed ischemia in ET3; however, 83.3% of patients in group R experienced ischemia earlier in ET4, without significant improvement in RPP, indicating the cessation of IPC (P < 0.0001). In group V, only 28% of patients demonstrated IPC cessation, with 72% still having the protective effect (P < 0.0069).. Repaglinide eliminated myocardial IPC, probably by its effect on the KATP channel. Vildagliptin did not damage this protective mechanism in a relevant way in patients with type 2 diabetes and CAD, suggesting a good alternative treatment in this population.

Topics: Adamantane; Aged; Carbamates; Coronary Artery Disease; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Ischemic Preconditioning; Male; Middle Aged; Nitriles; Piperidines; Prospective Studies; Pyrrolidines; Vildagliptin

Quantitative prediction of complex drug-drug interactions (DDIs) is challenging. Repaglinide is mainly metabolized by cytochrome-P-450 (CYP)2C8 and CYP3A4, and is also a substrate of organic anion transporting polypeptide (OATP)1B1. The purpose is to develop a physiologically based pharmacokinetic (PBPK) model to predict the pharmacokinetics and DDIs of repaglinide.. In vitro hepatic transport of repaglinide, gemfibrozil and gemfibrozil 1-O-β-glucuronide was characterized using sandwich-culture human hepatocytes. A PBPK model, implemented in Simcyp (Sheffield, UK), was developed utilizing in vitro transport and metabolic clearance data.. In vitro studies suggested significant active hepatic uptake of repaglinide. Mechanistic model adequately described repaglinide pharmacokinetics, and successfully predicted DDIs with several OATP1B1 and CYP3A4 inhibitors (<10% error). Furthermore, repaglinide-gemfibrozil interaction at therapeutic dose was closely predicted using in vitro fraction metabolism for CYP2C8 (0.71), when primarily considering reversible inhibition of OATP1B1 and mechanism-based inactivation of CYP2C8 by gemfibrozil and gemfibrozil 1-O-β-glucuronide.. This study demonstrated that hepatic uptake is rate-determining in the systemic clearance of repaglinide. The model quantitatively predicted several repaglinide DDIs, including the complex interactions with gemfibrozil. Both OATP1B1 and CYP2C8 inhibition contribute significantly to repaglinide-gemfibrozil interaction, and need to be considered for quantitative rationalization of DDIs with either drug.

Topics: Aryl Hydrocarbon Hydroxylases; Biological Transport, Active; Carbamates; Cell Line; Cytochrome P-450 CYP2C8; Drug Interactions; Gemfibrozil; Hepatocytes; Humans; Hypoglycemic Agents; Hypolipidemic Agents; Liver-Specific Organic Anion Transporter 1; Models, Biological; Organic Anion Transporters; Piperidines

A transdermal delivery system is warranted for repaglinide (RPG) which possesses half-life of 1 h and oral bioavailability of 56%. Ethosomes are useful tools for transdermal drug delivery.. To prepare and evaluate ethosomes as mode for transdermal delivery of RPG.. Ethosomes loaded with RPG were prepared from dipalmitoyl phosphatidylcholine and ethanol by the cold method. They were characterized using Fourier transform infrared spectroscopy and differential scanning calorimetry. They were evaluated for vesicle size, entrapment efficiency and ex-vivo skin permeation. Ethosomal composition was optimized using the 3(2) factorial design. Gel containing optimzsed ethosomes was studied for antidiabetic activity in rats.. RPG ethosomes possessing the size of 0.171-1.727 µm and entrapment efficiency of 75-92% were obtained. They demonstrated a significantly higher permeation (64-97% of the administered dose) across excised rat skin when compared to free drug and its hydro alcoholic solution. In-vivo, RPG ethosomal system caused sustained antidiabetic effect.. The lipid and ethanol concentration affected the physicochemical attributes and performance of ethosomes. The flexible ethosomes permeated the stratum corneum and improvized the availability of RPG for antidiabetic action. They prolonged the antidiabetic effect of RPG over a significantly longer period of time in comparison with the equivalent oral dose.. Ethosomal system can successfully deliver RPG transdermally; sustain its effect and thus reduce its dosing frequency. Ethosomes are useful for enhancing the efficacy of RPG in the treatment of diabetes.

Topics: Administration, Cutaneous; Animals; Carbamates; Drug Carriers; Drug Delivery Systems; Hypoglycemic Agents; Organ Culture Techniques; Piperidines; Rats; Rats, Wistar; Skin Absorption

Repaglinide is mainly metabolized by cytochrome P450 enzymes CYP2C8 and CYP3A4, and it is also a substrate to a hepatic uptake transporter, organic anion transporting polypeptide (OATP)1B1. The purpose of this study is to predict the dosing time-dependent pharmacokinetic interactions of repaglinide with rifampicin, using mechanistic models. In vitro hepatic transport of repaglinide, characterized using sandwich-cultured human hepatocytes, and intrinsic metabolic parameters were used to build a dynamic whole-body physiologically-based pharmacokinetic (PBPK) model. The PBPK model adequately described repaglinide plasma concentration-time profiles and successfully predicted area under the plasma concentration-time curve ratios of repaglinide (within ± 25% error), dosed (staggered 0-24 hours) after rifampicin treatment when primarily considering induction of CYP3A4 and reversible inhibition of OATP1B1 by rifampicin. Further, a static mechanistic "extended net-effect" model incorporating transport and metabolic disposition parameters of repaglinide and interaction potency of rifampicin was devised. Predictions based on the static model are similar to those observed in the clinic (average error ∼19%) and to those based on the PBPK model. Both the models suggested that the combined effect of increased gut extraction and decreased hepatic uptake caused minimal repaglinide systemic exposure change when repaglinide is dosed simultaneously or 1 hour after the rifampicin dose. On the other hand, isolated induction effect as a result of temporal separation of the two drugs translated to an approximate 5-fold reduction in repaglinide systemic exposure. In conclusion, both dynamic and static mechanistic models are instrumental in delineating the quantitative contribution of transport and metabolism in the dosing time-dependent repaglinide-rifampicin interactions.

Topics: Carbamates; Cytochrome P-450 CYP3A; Drug Interactions; Enzyme Induction; Humans; Liver-Specific Organic Anion Transporter 1; Models, Theoretical; Organic Anion Transporters; Piperidines; Rifampin

The pancreatic K(ATP) channel, SUR1/Kir6.2, couples insulin secretion to the plasma glucose level. The channel is an octamer with four Kir6.2 subunits forming the pore and four sulphonylurea receptors (SUR1) regulating channel activity. SUR1 is an ABC protein with adenosine triphosphate (ATP)ase activity which activates the channel. It also contains the binding site for antidiabetic drugs like glibenclamide and repaglinide which close the channel by disrupting the stimulatory effect SUR-ATPase (MgATP-dependent) and by stabilising a long-lived closed channel state (MgATP-independent). In this study, we examined the effects of progressive truncation of the Kir6.2 N-terminus up to 20 amino acids on equilibrium binding and channel closure by glibenclamide and repaglinide, on the channel activating effect of the opener, 6-chloro-3-(1-methylcyclobutyl)amino-4H-thieno[3,2-e]-1,2,4thiadiazine 1,1-dioxide (NNC 55-0462), and on the binding kinetics of [(3)H]glibenclamide. Kir and SUR were transiently coexpressed in HEK cells and [(3)H]glibenclamide binding and patch-clamp experiments were performed in whole cells at 37°C and in isolated inside/out patches at 22°C. Truncation of the first 5 N-terminal amino acids abolished most of the affinity increase for glibenclamide and repaglinide that is produced by the association of Kir6.2 with SUR1. Progressive truncation continuously reduced the potency and efficacy of these drugs in closing the channel and impaired the ability to stabilise the closed state more than the ability to disrupt channel stimulation by SUR-ATPase. The effects of NNC 55-0462 were unchanged. Progressive truncation also speeded up dissociation of [(3)H]glibenclamide from the channel when dissociation was induced by an excess of (unlabelled) glibenclamide. This suggests the existence of a putative low affinity glibenclamide site on the channel whose affinity increases upon truncation. The data show that progressive truncation of the Kir6.2 N-terminus impairs the transduction of drug binding into channel closure more strongly than drug binding but leaves the effect of the opener NNC 55-0462 unchanged.

Topics: Animals; ATP-Binding Cassette Transporters; Binding Sites; Carbamates; Glyburide; HEK293 Cells; Humans; Hypoglycemic Agents; Pancreas; Patch-Clamp Techniques; Piperidines; Potassium Channels, Inwardly Rectifying; Protein Binding; Rats; Receptors, Drug; Sulfonylurea Receptors

In Germany, coverage decisions in the statutory health insurance (SHI) system are based on the principles of evidence-based medicine. Recently, an evidence assessment by the Institute for Quality and Efficiency in Health Care (IQWiG) of the oral antidiabetics of the glinide class showed that their long-term benefit is not proven. Accordingly, the responsible Federal Joint Committee (G-BA) decided to exclude glinides from prescription in the SHI system. This was, however, objected to by the Ministry of Health, which is charged with legal supervision. We use this case to illustrate the path from evidence assessments to coverage decisions in Germany against the background of the latest health reform, which has changed the legal requirements for evidence assessments and the ensuing coverage decisions.

Topics: Carbamates; Cost Control; Cost-Benefit Analysis; Costs and Cost Analysis; Cyclohexanes; Diabetes Mellitus; Eligibility Determination; Evidence-Based Medicine; Germany; Health Care Reform; Health Policy; Humans; Hypoglycemic Agents; Insurance Coverage; Nateglinide; National Health Programs; Phenylalanine; Piperidines; Prescription Drugs; Reimbursement Mechanisms; Technology Assessment, Biomedical

The purpose of this study was to investigate the effects of efonidipine on the pharmacokinetics and pharmacodynamics of repaglinide in rats. The pharmacokinetic parameters of repaglinide and blood glucose concentrations were also determined in rats after oral (0.5 mg/kg) and intravenous (0.2 mg/kg) administration of repaglinide to rats in the presence and absence of efonidipine (1 and 3 mg/kg). Efonidipine inhibited CYP3A4 activity with an IC(50) value of 0.08 μM, and efonidipine significantly inhibited P-gp activity in a concentration-dependent manner. Compared to the oral control group, efonidipine significantly increased the area under the plasma concentration-time curve (AUC(0-∞)) (P < 0.01 for 3 mg/kg) and the peak plasma concentration (C (max)) (P < 0.05 for 3 mg/kg) of repaglinide by 51.3 and 28.6%, respectively. Efonidipine also significantly (P < 0.01 for 3 mg/kg) increased the absolute bioavailability (AB) of repaglinide by 51.5% compared to the oral control group (33.6%). Moreover, efonidipine significantly increased (P < 0.05 for 3 mg/kg) the AUC(0-∞) of intravenously administered repaglinide. Consistent with these kinetic alterations, the hypoglycemic effect in the concurrent administration group was more pronounced than that in the control group (i.e., repaglinide alone) when the drug was given orally. A pharmacokinetic/dynamic model involving 2-compartment open model with inhibition in absorption/elimination and an indirect response model was apparently sufficient in estimating the concentration-time and effect-time profiles of repaglinide with or without efonidipine. Present study has raised the awareness of potential drug interactions by concomitant use of efonidipine with repaglinide, since efonidipine may alter the absorption and/or elimination of repaglinide by the inhibition of CYP3A4 and P-gp efflux pump. Therefore, the concurrent use of efonidipine with repaglinide may require a close monitoring for potential drug interactions.

Topics: Animals; Antihypertensive Agents; Area Under Curve; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biocatalysis; Biological Availability; Blood Glucose; Carbamates; Cell Line, Tumor; Cytochrome P-450 CYP3A; Cytochrome P-450 CYP3A Inhibitors; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Dihydropyridines; Drug Interactions; Humans; Hypoglycemic Agents; Ketoconazole; Male; Models, Biological; Nitrophenols; Organophosphorus Compounds; Pharmacological Phenomena; Piperidines; Rats; Rats, Sprague-Dawley; Rhodamine 123

Dyslipidemia is common in patients with type 2 diabetes. Statins are used as the first choice in treatment of diabetic dyslipidemia. Atorvastatin represents a first-line treatment option, alongside other hydroxyl methylglutaryl coenzyme A reductase inhibitors. Repaglinide is a short-acting, oral, insulin secretagogue that is used in the treatment of type 2 diabetes mellitus. Both the category of drugs undergo extensive metabolism with cytochrome enzyme system. This may lead to drug-drug interaction problems with altered repaglinide activity which is cautious. Repaglinide/atorvastatin/atorvastatin + repaglinide were administered orally to normal, diabetic rats, and to normal rabbits. Blood samples were collected at different time intervals and were analyzed for blood glucose by GOD-POD method using commercial glucose kits and repaglinide estimation in plasma by HPLC method. Diabetes was induced by alloxan 100 mg/kg body weight administered by I.P route. In the presence of atorvastatin, repaglinide activity was increased and maintained for longer period in diabetic rats compared with repaglinide matching control. The present study concludes co-administration of atorvastatin was found to improve repaglinide responses significantly in diabetic rats and improved glucose metabolism of atorvastatin played an important role and increased repaglinide levels by competitive CYP 3A4 enzyme inhibition by atorvastatin could be added advantage for anti hyperglycemic activity.

Topics: Animals; Atorvastatin; Blood Glucose; Carbamates; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Diabetes Mellitus, Experimental; Drug Interactions; Heptanoic Acids; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoglycemic Agents; Piperidines; Pyrroles; Rabbits; Rats

Chronic kidney disease, or renal impairment (RI) can increase plasma levels for drugs that are primarily renally cleared and for some drugs whose renal elimination is not a major pathway. We constructed physiologically based pharmacokinetic (PBPK) models for 3 nonrenally eliminated drugs (sildenafil, repaglinide, and telithromycin). These models integrate drug-dependent parameters derived from in vitro, in silico, and in vivo data, and system-dependent parameters that are independent of the test drugs. Plasma pharmacokinetic profiles of test drugs were simulated in subjects with severe RI and normal renal function, respectively. The simulated versus observed areas under the concentration versus time curve changes (AUCR, severe RI/normal) were comparable for sildenafil (2.2 vs 2.0) and telithromycin (1.6 vs 1.9). For repaglinide, the initial, simulated AUCR was lower than that observed (1.2 vs 3.0). The underestimation was corrected once the estimated changes in transporter activity were incorporated into the model. The simulated AUCR values were confirmed using a static, clearance concept model. The PBPK models were further used to evaluate the changes in pharmacokinetic profiles of sildenafil metabolite by RI and of telithromycin by RI and co-administration with ketoconazole. The simulations demonstrate the utility and challenges of the PBPK approach in evaluating the pharmacokinetics of nonrenally cleared drugs in subjects with RI.

Topics: Area Under Curve; Carbamates; Chronic Disease; Computer Simulation; Drug Interactions; Humans; Ketolides; Kidney Diseases; Models, Biological; Piperazines; Piperidines; Purines; Sildenafil Citrate; Sulfones

In order to improve the dissolution and absorption of the water insoluble drug repaglinide, a solid dispersion was developed by solvent method using polyvinylpyrrolidone K30 (PVP K30) as the hydrophilic carrier for the first time. Studies indicated that both solubility and the dissolution rate of repaglinide were significantly increased in the solid dispersion system compared with that of repaglinide raw material or physical mixtures. The repaglinide solid dispersions with PVP K30 solid state was characterized by polarizing microscopy, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). DSC and XRD studies indicated that repaglinide existed in an amorphous form in the solid dispersion. FT-IR analysis demonstrated the presence of intermolecular hydrogen bonding between repaglinide and PVP K30 in the solid dispersion. In the in situ gastrointestinal perfusion experiment, solid dispersion was shown to remarkably enhance the absorption of repaglinide in stomach and all segments of intestine. In vivo pharmacokinetic study in rats showed that immediate and complete release of repaglinide from the solid dispersion resulted in rapid absorption that significantly increased the bioavailability and the maximum plasma concentration over repaglinide raw material. These results demonstrated PVP K30 was an appropriate carrier for solid dispersion of repaglinide, with increased dissolution and oral absorption.

Topics: Animals; Biological Availability; Calorimetry, Differential Scanning; Carbamates; Chromatography, High Pressure Liquid; Drug Carriers; Drug Compounding; Drug Interactions; Gastric Mucosa; Hydrophobic and Hydrophilic Interactions; Hypoglycemic Agents; Intestinal Absorption; Intestinal Mucosa; Male; Microscopy, Polarization; Molecular Structure; Piperidines; Povidone; Rats; Rats, Wistar; Solubility; Spectroscopy, Fourier Transform Infrared; Tandem Mass Spectrometry; X-Ray Diffraction

The predictive power of using in vitro systems in combination with physiologically based pharmacokinetic (PBPK) modeling to elucidate the relative importance of metabolism and carrier-mediated transport for the pharmacokinetics was evaluated using repaglinide as a model compound and pig as the test system. Repaglinide was chosen as model drug as previous studies in humans have shown that repaglinide is subject to both carrier-mediated influx to the liver cells and extensive hepatic metabolism. A multiple sampling site model in pig was chosen since it provides detailed in vivo information about the liver disposition. The underlying assumption was that both metabolism and carrier-mediated transport are also important for the hepatic disposition of repaglinide in pigs. Microsomes and primary hepatocytes were used for in vitro evaluation of enzyme kinetics and cellular disposition, respectively. In vitro data were generated both with and without metabolism inhibitors (ketoconazole, bezafibrate and trimethoprim) and transport inhibitors (diclofenac and quinine) providing input into a semi-PBPK model. In vivo data were also generated with and without the same enzyme and transporter inhibitors, alone and in combination. The pigs were given repaglinide as intravenous infusions with and without inhibitors in a sequential manner, i.e., a control phase and a test phase. Parameters describing the passive and carrier-mediated flux as well as metabolism were estimated in the control phase. The result from test phase was used to gain further knowledge of the findings from the control phase. The in vivo pig model enabled simultaneous sampling from plasma (pre- and postliver and peripheral) as well as from bile and urine. A semi-PBPK model consisting of 11 compartments (6 tissues + 5 sampling sites) was constructed for the mechanistic elucidation of the liver disposition, in vitro based in vivo predictions, sensitivity analyses and estimations of individual pharmacokinetic parameters. Both in vitro and in vivo results showed that carrier-mediated influx was important for the liver disposition. The in vivo findings were supported by the result from the test phase where hepatic clearance (4.3 mL min⁻¹ kg⁻¹) was decreased by 29% (metabolism inhibition), 43% (transport inhibition) and 57% (metabolism + transport inhibition). These effects were in good agreement with predicted levels. This study suggests that both metabolism and carrier-mediated uptake are of significant impor

Topics: Animals; Biological Transport; Carbamates; Drug Interactions; Hepatocytes; Liver; Microsomes, Liver; Piperidines; Swine

The aim of the present study was to evaluate the impact of the UCP2-866 G/A polymorphism on the efficacy of repaglinide in treating patients with diabetes mellitus type 2 (T2DM). 370 patients with T2DM and 166 healthy volunteers were enrolled to identify UCP2-866 G/A genotypes. 16 patients with GG genotype, 14 with GA genotype and 11 with AA genotype of UCP2-866 G/A underwent an 8-week repaglinide treatment regimen. There were no differences in allele frequency of UCP2-866 G/A between T2DM patients and control subjects. The patient with AA genotype of UCP2-866 G/A had higher levels of fasting plasma glucose (FPG), 30-min and 2-h postload plasma glucose, glycated haemoglobin (HbA1c), and lower concentrations of 30-min and 2-h postload plasma insulin, homeostasis model assessment of beta cell function (HOMA-beta), deltaI30/deltaG30 compared with GG genotype. After repaglinide treatment for 8 consecutive weeks, we found that A allele carriers of UCP2 in the T2DM patients had smaller decrease in FPG (P < 0.05) and HbA1c (P < 0.05), and smaller increase in 30-min postload plasma insulin (P < 0.01) compared with GG genotypes. We demonstrated that UCP2-866 G/A polymorphism is associated with the therapeutic efficacy of repaglinide in Chinese T2DM patients.

Topics: Adult; Aged; Alleles; Asian People; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; DNA Primers; Female; Genotype; Humans; Hypoglycemic Agents; Insulin; Insulin-Secreting Cells; Ion Channels; Male; Middle Aged; Mitochondrial Proteins; Pancreatic Function Tests; Piperidines; Polymerase Chain Reaction; Uncoupling Protein 2

Repaglinide is presently recommended by the U.S. Food and Drug Administration as a clinical CYP2C8 probe, yet current in vitro and clinical data are inconsistent concerning the role of this enzyme in repaglinide elimination. The aim of the current study was to perform a comprehensive investigation of repaglinide metabolic pathways and assess their contribution to the overall clearance. Formation of four repaglinide metabolites was characterized using in vitro systems with differential complexity. Full kinetic profiles for the formation of M1, M2, M4, and repaglinide glucuronide were obtained in pooled cryopreserved human hepatocytes, human liver microsomes, human S9 fractions, and recombinant cytochrome P450 enzymes. Distinct differences in clearance ratios were observed between CYP3A4 and CYP2C8 for M1 and M4 formation, resulting in a 60-fold M1/M4 ratio in recombinant (r) CYP3A4, in contrast to 0.05 in rCYP2C8. Unbound K(m) values were within 2-fold for each metabolite across all in vitro systems investigated. A major system difference was seen in clearances for the formation of M2, which is suggested to be a main metabolite of repaglinide in vivo. An approximately 7-fold higher unbound intrinsic clearance was observed in hepatocytes and S9 fractions in comparison to microsomes; the involvement of aldehyde dehydrogenase in M2 formation was shown for the first time. This systematic analysis revealed a comparable in vitro contribution from CYP2C8 and CYP3A4 to the metabolism of repaglinide (<50%), whereas the contribution of glucuronidation ranged from 2 to 20%, depending on the in vitro system used. The repaglinide M4 metabolic pathway is proposed as a specific CYP2C8 probe for the assessment of drug-drug interactions.

Topics: Aryl Hydrocarbon Hydroxylases; Carbamates; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Drug Interactions; Glucuronides; Hepatocytes; Humans; Hypoglycemic Agents; Kinetics; Metabolic Networks and Pathways; Microsomes, Liver; Piperidines

The influence of microwave technology on the in vitro dissolution rate and in vivo antihyperglycemic activity of a poorly water soluble drug, repaglinide (RG) was studied. Solid dispersions were prepared by conventional fusion method and microwave method using poloxamer 188. The dispersions were characterized by solubility study, dissolution study, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Microwave generated solid dispersions exhibited remarkable improvement in solubility and dissolution rate compared to that of pure RG. Results of DSC, XRD and SEM study showed conversion of crystalline form of RG to amorphous form. In vivo studies revealed that the microwave generated solid dispersion showed significant improvements in antihyperglycemic activity as compared to RG alone, thus confirming the advantage of improved pharmacological activity of RG by microwave method. In conclusion, microwave method could be considered as simple, efficient and solvent free promising alternative method to prepare solid dispersion of poorly water soluble drug RG with significant enhancement in solubility, dissolution rate and antihyperglycemic activity.

Topics: Animals; Blood Glucose; Calorimetry, Differential Scanning; Carbamates; Female; Hypoglycemic Agents; Male; Microwaves; Piperidines; Poloxamer; Rats; Rats, Wistar; Solubility; Spectroscopy, Fourier Transform Infrared; X-Ray Diffraction

The present study was undertaken to determine oxidative/nitrosative stress in aqueous humor of alloxan-induced hyperglycemic rabbits and to investigate the effects of two oral antidiabetic drugs, pioglitazone from peroxisome proliferator-activated receptor gamma (PPARγ) agonists and repaglinide from nonsulfonylurea K(ATP) channel blockers. Ascorbic acid (AA), glutathione (GSH), total antioxidant status (TAS), lipid peroxidation products (LPO), total nitrites (NO(2)), advanced oxidized protein products (AOPP), and protein carbonyl groups (PCG) were determined using respective colorimetric and ELISA methods. In our hyperglycemic animals, AA decreased by 77%, GSH by 45%, and TAS by 66% as compared to control animals. Simultaneously, LPO increased by 78%, PCG by 60%, AOPP by 84%, and NO(2) by 70%. In pioglitazone-treated animals, AA and TAS increased above control values while GSH and PCG were normalized. In turn, LPO was reduced by 54%, AOPP by 84%, and NO(2) by 24%, in relation to hyperglycemic rabbits. With repaglinide, AA and TAS were normalized, GSH increased by 20%, while LPO decreased by 45%. Our results show that pioglitazone and repaglinide differ significantly in their ability to ameliorate the parameters like NO(2), PCG, and AOPP. In this area, the multimodal action of pioglitazone as PPARγ agonist is probably essential.

Topics: Animals; Antioxidants; Aqueous Humor; Carbamates; Diabetes Mellitus, Experimental; Glutathione Peroxidase; Hyperglycemia; Hypoglycemic Agents; Lipid Peroxidation; Male; Oxidative Stress; Pioglitazone; Piperidines; Rabbits; Thiazolidinediones

In this paper we analyse the discrepancies that exist in the widespread prescription of metformin in patients with type 2 diabetes and the lack of guidelines concerning its prescription in the different stages of renal failure. This cross-sectional study includes 304 patients with type 2 diabetes treated with oral antidiabetic drugs (ADOs) and a glomerular filtration rate (estimated GFR) <60ml/min/1.73m2. Patients were attended in consecutive visits to primary health centres or in hospital departments of endocrinology or nephrology during 2010. We studied the frequency of metformin and other ADO prescriptions according to renal function and the department in which the patient was treated. The ADO most frequently prescribed was metformin (54.9%), followed by repaglinide (47.7%), DPP4 inhibitors (28.6%), and sulfonylureas (18.4%). However, in nephrology departments, repaglinide was more frequently prescribed than metformin (P<.001), whereas in primary health centres, the prescription of DPP4 inhibitors increased. In patients with an estimated GFR of 15-29ml/min/1.73m2, metformin (13.3%) and sulfonylureas were the least prescribed, whereas metformin was much more frequently prescribed (70.0%) when estimated GFR was 45-59ml/min/1.73m2 (P<.001). In contrast, patients with an estimated GFR of 15-29ml/min/1.73m2 were mainly prescribed repaglinide (76.7%), as opposed to patients with an estimated GFR of 45-59ml/min/1.73m2 (38.9%) (P<.001). Substantial evidence suggests that the recommendations for the use of ADO should be modified. This would lead to safely prescribing ADO in patients with an estimated GFR<60ml/min/1.73m2, and more importantly in medical practice, according to the law.

Topics: Acidosis, Lactic; Aged; Carbamates; Consensus Development Conferences as Topic; Contraindications; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Disease Management; Drug Utilization; Endocrinology; Female; Follow-Up Studies; Glomerular Filtration Rate; Hospital Departments; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Nephrology; Piperidines; Practice Guidelines as Topic; Primary Health Care; Professional Practice; Societies, Medical; Spain; Sulfonylurea Compounds

This study used the general applicability of 2,6-didi-o-methyl-β-cyclodextrin (DM-β-CD) as the chiral selector in capillary electrophoresis for fast and efficient chiral separation of repaglinide enantiomers. A systematic study of the parameters affecting separation was performed with UV detection at 243 nm. The optimum conditions were determined to be 1.25% (w/v) DM-β-CD in 20 mM sodium phosphate (pH 2.5) as the running buffer and separation voltage at 20 kV. DM-β-CD had the best enantiomer resolution properties under the tested conditions, whereas other β-cyclodextrins showed inferior performances or no performance. The proposed method had a linear calibration curve in the concentration range of 12.5-400 µg/mL. The limit of detection was 100 ng/mL. The intra-day and inter-day precisions were 2.8 and 3.2%, respectively. Recoveries of 97.9-100.9% were obtained. The proposed method was fast and convenient, and was determined to be efficient for separating enantiomers and applicable for analyzing repaglinide enantiomers in quality control of pharmaceutical production.

Topics: beta-Cyclodextrins; Carbamates; Drug Contamination; Electrophoresis, Capillary; Hydrogen-Ion Concentration; Limit of Detection; Linear Models; Piperidines; Reproducibility of Results; Stereoisomerism; Tablets

Interindividual variability in activity of uptake transporters is evident in vivo, yet limited data exist in vitro, confounding in vitro-in vivo extrapolation. The uptake kinetics of seven organic anion-transporting polypeptide substrates was investigated over a concentration range in plated cryopreserved human hepatocytes. Active uptake clearance (CL(active, u)), bidirectional passive diffusion (P(diff)), intracellular binding, and metabolism were estimated for bosentan, pitavastatin, pravastatin, repaglinide, rosuvastatin, telmisartan, and valsartan in HU4122 donor using a mechanistic two-compartment model in Matlab. Full uptake kinetics of rosuvastatin and repaglinide were also characterized in two additional donors, whereas for the remaining drugs CL(active, u) was estimated at a single concentration. The unbound affinity constant (K(m, u)) and P(diff) values were consistent across donors, whereas V(max) was on average up to 2.8-fold greater in donor HU4122. Consistency in K(m, u) values allowed extrapolation of single concentration uptake activity data and assessment of interindividual variability in CL(active) across donors. The maximal contribution of active transport to total uptake differed among donors, for example, 85 to 96% and 68 to 87% for rosuvastatin and repaglinide, respectively; however, in all cases the active process was the major contributor. In vitro-in vivo extrapolation indicated a general underprediction of hepatic intrinsic clearance, an average empirical scaling factor of 17.1 was estimated on the basis of seven drugs investigated in three hepatocyte donors, and donor-specific differences in empirical factors are discussed. Uptake K(m, u) and CL(active, u) were on average 4.3- and 7.1-fold lower in human hepatocytes compared with our previously published rat data. A strategy for the use of rat uptake data to facilitate the experimental design in human hepatocytes is discussed.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Antihypertensive Agents; Benzimidazoles; Benzoates; Biological Transport; Bosentan; Carbamates; Dose-Response Relationship, Drug; Drug Interactions; Fluorobenzenes; Hepatocytes; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoglycemic Agents; Kinetics; Models, Biological; Organic Anion Transporters; Piperidines; Pravastatin; Pyrimidines; Quinolines; Rats; Rosuvastatin Calcium; Species Specificity; Sulfonamides; Telmisartan; Tetrazoles; Valine; Valsartan

A simple and highly sensitive spectrofluorimetric method was developed and validated for determination of the antidiabetic agent repaglinide (RG) in tablets. The proposed method is based on measurement of the native fluorescence of RG in 0.1 M H(2)SO(4)/methanol medium at 360 nm after excitation at 243 nm. The method showed a linear dependence of the relative fluorescence intensity on drug concentration over the range of 0.02-0.50 μg mL(-1) with lower detection limit of 6.0 ng mL(-1) and lower quantification limit of 18 ng mL(-1). The method was successfully applied for determination of RG in different tablets and the obtained results were in good agreement with those obtained by the official method. The proposed method was extended to investigate the kinetics of oxidative degradation of the drug. A proposal for the degradation pathway was postulated.

Topics: Carbamates; Drug Stability; Linear Models; Methanol; Piperidines; Solvents; Spectrometry, Fluorescence; Sulfuric Acids; Tablets; Temperature; Time Factors

Sperm chemotaxis occurs widely in animals and plants and plays an important role in the success of fertilization. Several studies have recently demonstrated that Ca(2+) influx through specific Ca(2+) channels is a prerequisite for sperm chemotactic movement. However, the regulator that modulates flagellar movement in response to Ca(2+) is unknown. Here we show that a neuronal calcium sensor, calaxin, directly acts on outer-arm dynein and regulates specific flagellar movement during sperm chemotaxis. Calaxin inhibition resulted in significant loss of sperm chemotactic movement, despite normal increases in intracellular calcium concentration. Using a demembranated sperm model, we demonstrate that calaxin is essential for generation and propagation of Ca(2+)-induced asymmetric flagellar bending. An in vitro motility assay revealed that calaxin directly suppressed the velocity of microtubule sliding by outer-arm dynein at high Ca(2+) concentrations. This study describes the missing link between chemoattractant-mediated Ca(2+) signaling and motor-driven microtubule sliding during sperm chemotaxis.

Topics: Animals; Calcium Signaling; Carbamates; Chemotaxis; Ciona intestinalis; Dyneins; Intracellular Calcium-Sensing Proteins; Male; Microtubules; Models, Biological; Molecular Motor Proteins; Piperidines; Sperm Motility; Sperm Tail; Spermatozoa

Conventional mammillary models are frequently used for pharmacokinetic (PK) analysis when only blood or plasma data are available. Such models depend on the quality of the drug disposition data and have vague biological features. An alternative minimal-physiologically-based PK (minimal-PBPK) modeling approach is proposed which inherits and lumps major physiologic attributes from whole-body PBPK models. The body and model are represented as actual blood and tissue (usually total body weight) volumes, fractions (f ( d )) of cardiac output with Fick's Law of Perfusion, tissue/blood partitioning (K ( p )), and systemic or intrinsic clearance. Analyzing only blood or plasma concentrations versus time, the minimal-PBPK models parsimoniously generate physiologically-relevant PK parameters which are more easily interpreted than those from mammillary models. The minimal-PBPK models were applied to four types of therapeutic agents and conditions. The models well captured the human PK profiles of 22 selected beta-lactam antibiotics allowing comparison of fitted and calculated K ( p ) values. Adding a classical hepatic compartment with hepatic blood flow allowed joint fitting of oral and intravenous (IV) data for four hepatic elimination drugs (dihydrocodeine, verapamil, repaglinide, midazolam) providing separate estimates of hepatic intrinsic clearance, non-hepatic clearance, and pre-hepatic bioavailability. The basic model was integrated with allometric scaling principles to simultaneously describe moxifloxacin PK in five species with common K ( p ) and f ( d ) values. A basic model assigning clearance to the tissue compartment well characterized plasma concentrations of six monoclonal antibodies in human subjects, providing good concordance of predictions with expected tissue kinetics. The proposed minimal-PBPK modeling approach offers an alternative and more rational basis for assessing PK than compartmental models.

Topics: Anti-Bacterial Agents; Antibodies, Monoclonal; beta-Lactams; Biological Availability; Carbamates; Codeine; Humans; Kinetics; Liver; Midazolam; Models, Biological; Piperidines; Regional Blood Flow; Verapamil

Human papillomaviruses are responsible for multiple human diseases, including cervical cancer caused by multiple high-risk types and genital warts caused by the low-risk types 6 and 11. Based on the research indicating that low-risk HPV could be successfully targeted by inhibitors of viral DNA replication, we carried out several high-throughput screens for inhibitors of DNA replication activities. Two series were identified in screens for inhibitors of the interaction between the viral proteins E1 and E2. The two series were demonstrated to bind to overlapping sites on the transactivation domain of E2, at the E1-binding interface, by a series of biochemical and biophysical experiments. A member of the first series was also cocrystallized with the E2 transactivation domain. For both series, structure-activity investigations are described, which resulted in several hundred fold improvements in activity. The best compounds in each series had low nanomolar activity against the HPV11 E1-E2 interaction, and EC(50) values in cellular DNA replication assays of approximately 1 μM. Binding modes for the two series are compared, and some general conclusions about the discovery of protein-protein interaction inhibitors are drawn from the work described.

Topics: Antiviral Agents; Binding Sites; Carbamates; DNA-Binding Proteins; Drug Evaluation, Preclinical; Humans; Indans; Molecular Dynamics Simulation; Papillomaviridae; Piperidines; Protein Binding; Protein Conformation; Viral Proteins

Pathological changes identified in different tissues in hyperglycemic state are undoubtedly connected with increased oxidative/nitrosative stress and inflammation. In our study myeloperoxidase (MPO), nitrotyrosine and lipid peroxidation were enhanced in the heart and lung of alloxan-treated hyperglycemic animals. Additionally, pulmonary aconitase was inhibited. In the testis the changes occurred as an increase of MPO and lipid peroxidation, and as a decrease of aconitase. The effects of two different antidiabetics, the peroxisome proliferator activated receptor gamma (PPARγ) agonist, pioglitazone, and a short acting insulin secretagogue, repaglinide, on the mentioned parameters, were investigated and compared. The insulin deficient alloxan-induced hyperglycemic animals were used to differentiate a direct anti-oxidative effect of the drugs from secondary effects mediated via increased insulin sensitivity or secretion. Pioglitazone acted by normalization of pulmonary and testicular aconitase, normalization of pulmonary and cardiac nitrotyrosine, reduction of pulmonary and testicular MPO, and by reduction of lipid peroxidation in all tissues examined. Repaglinide prevented oxidative changes by normalization of aconitase activity in the lung and testis, and by reduction of lipid peroxidation and nitrotyrosine in the heart and lung. At the same time, no effect of this drug on MPO was observed. Finally, principal component analysis was performed to explore and visualize similarities and differences of the results obtained for the both drugs.

Topics: Aconitate Hydratase; Administration, Oral; Alloxan; Animals; Blood Glucose; Body Weight; Carbamates; Enzyme Activation; Hyperglycemia; Hypoglycemic Agents; Inflammation; Insulin; Lipid Peroxidation; Male; Oxidative Stress; Pioglitazone; Piperidines; Rabbits; Reactive Nitrogen Species; Thiazolidinediones

The pharmacokinetics of repaglinide shows pronounced interindividual variability, for which several reasons have been considered, including interactions with drugs inhibiting CYP2C8 and CYP2C8 genetic polymorphism. However, existing data on the role of genetic polymorphisms in repaglinide disposition are not fully consistent. We studied the effect of CYP2C8*3 on the pharmacokinetics and pharmacodynamics of repaglinide in 29 healthy whites carrying CYP2C8*3/*3 (n = 4), CYP2C8*1/*3 (n = 13), or CYP2C8*1/*1 (n = 12). After administration of a single dose of 2 mg of repaglinide, blood was drawn for assessment of repaglinide pharmacokinetics and pharmacodynamics, and urine was collected to quantify the main repaglinide metabolites M1 and M4 up to 24 h postdose. Repaglinide and the metabolites were quantified by liquid chromatography-tandem mass spectrometry. Considering only the effect of CYP2C8*3, the mean (95% confidence interval) area under the time-concentration curve (AUC) from zero to infinity of repaglinide was 72.4 (6.7-138.0), 97.2 (59.2-135.2), and 105.9 (52.4-159.3) ng · ml(-1) · h and the maximal concentration (C(max)) was 38.5 (3.8-73.2), 50.3 (37.5-63.0), and 60.3 (31.5-89.1) ng · ml(-1), respectively, in carriers of CYP2C8*3/*3, CYP2C8*1/*3, and CYP2C8*1/*1 [p > 0.05, one-way analysis of variance (ANOVA)]. In addition, for urinary metabolite excretion and pharmacodynamic parameters, i.e., mean and maximal changes in insulin and glucose concentration, no significant differences between CYP2C8 genotypes were observed. Likewise, no significant effects on the pharmacokinetics or pharmacodynamics were observed when AUC and C(max) of repaglinide were corrected for reported effects of the SLCO1B1 521T>C polymorphism or when both polymorphisms were tested in a two-way ANOVA. In conclusion, CYP2C8*3 does not seem to play an important role in the pharmacokinetics and pharmacodynamics of repaglinide given in a therapeutic dose.

Topics: Adult; Aryl Hydrocarbon Hydroxylases; Blood Glucose; Carbamates; Cytochrome P-450 CYP2C8; Drug Interactions; Female; Genotype; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Piperidines; Polymorphism, Single Nucleotide

Repaglinide is commonly used in the treatment of patients with type 2 diabetes mellitus to reduce postprandial hyperglycemia. The objective of this research was to study the effects of SLCO1B1 polymorphisms on the pharmacokinetics and pharmacodynamics of repaglinide in healthy Chinese volunteers.. A total of 22 healthy young male participants were recruited from a pool of pharmacogenetically characterized participants genotyped for SLCO1B1, CYP3A4, and CYP2C8 SNPs by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Volunteers with CYP2C8*3 and CYP3A4*4 alleles were excluded from the clinical study. Then selected volunteers took part in the clinical pharmacokinetic study, receiving 2 mg repaglinide.. Healthy participants with SLCO1B1*1A/*1B or *1A/*1A genotype and SLCO1B1 *15/*1A or *5/*1A genotype had significantly higher AUC(0-∞) than participants with SLCO1B1*1B/*1B genotype, with the former showing an increase over the latter of 39.81 and 42.09%, respectively (P = 0.028, 0.032). The clearance in the former two genotype groups was significantly attenuated (by 27.39 and 28.55%, respectively) compared with individuals with SLCO1B1*1B/*1B genotype (P = 0.015, 0.019). No significant differences in blood glucose-lowering effect were observed among three genotype groups.. SLCO1B1*1B/*1B genotype is associated with reduced pharmacokinetic exposure after a single dose oral administration of 2 mg repaglinide, including decreased AUC(0-∞) and increased clearance of repaglinide. Moreover, this polymorphism of SLCO1B1 has significant influence on the pharmacokinetics of repaglinide, but no effects on its pharmacodynamics.

Topics: Adult; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Asian People; Carbamates; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Genotype; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Male; Organic Anion Transporters; Piperidines; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Polymorphism, Single Nucleotide; Prospective Studies; Young Adult

Role of 2-Deoxy-D-glucose (2-DG) in reversing the Indian red scorpion (Mesobuthus tamulus concanesis Pocock, MBT) venom-induced toxicity was examined. Femoral arterial pressure, ECG and respiratory movements were recorded in urethane anesthetized rats. Plasma glucose and serum insulin levels were also estimated. Intravenous injection of 5 mg/kg MBT venom produced immediate decrease in mean arterial pressure, heart rate and respiratory frequency followed by an increase and subsequent progressive decrease. ECG pattern exhibited ischaemic changes. There was hyperinsulinemia after venom without corresponding decrease in plasma glucose. The animals died within 37 +/- 9 min and demonstrated significant increase in pulmonary water content. 2-DG pretreatment (0.5 g/kg, iv) improved the cardiopulmonary abnormalities induced by venom and the animals survived for nearly 120 min. There was no hyperinsulinemia and increased pulmonary water content in these animals. In insulin (2 IU/kg) treated rats, the MBT venom-induced cardiopulmonary abnormalities were attenuated and ECG abnormalities were reversed. The pulmonary water content in these animals exhibited a decreasing trend and the animals survived for 120 min. Repaglinide (10 microg/kg, iv) pretreatment failed to reverse the venom-induced cardiopulmonary changes including the increased pulmonary water content. The survival time was similar to venom only group. The present results reveal that 2-DG reverses the venom-induced cardiopulmonary toxicity probably by restoring insulin sensitivity.

Topics: Anesthesia; Animals; Blood Glucose; Carbamates; Cardiovascular Abnormalities; Deoxyglucose; Hyperglycemia; India; Insulin; Lung Diseases; Myocardial Ischemia; Piperidines; Pulmonary Edema; Rats; Respiration; Scorpion Venoms; Ultrasonography

The purpose of present study is to examine effect of binary lipid matrix (combination of lipids) on the entrapment and storage stability of repaglinide (RG) loaded solid lipid nanoparticles (SLN). Solid lipid nanoparticles were prepared by modified solvent injection method for oral delivery to improve the bioavailability of RG, an antidiabetic drug. The stearic acid and tristearin were used to form lipid core materials, and Pluronic-F68 was used as a stabilizer. Nanoparticles were characterized by evaluating their particle size, zeta potential, entrapment efficiency, drug loading, solid-state studies (differential scanning calorimetry, X-ray diffraction), in vitro drug release, particle surface (transmission electron microscopy analysis with electron diffraction pattern), stability study in gastrointestinal fluids (GIFs) and storage stability at 30 °C/65% RH for 3 months. The characterization of SLN suggested that binary lipid matrix based nanoparticles had better drug entrapment and loading, desired release characteristics, stable in GIFs and significantly higher storage stability compared with single lipid formulations. Pharmacodynamic (blood glucose, blood cholesterol, blood triglyceride levels) and pharmacokinetic (AUC, T(max), peak plasma concentrations, K, t(1/2), mean residence time and relative bioavailabilities) studies were performed for the selected formulations. These studies indicate that the formulation based on binary lipid matrix significantly improves the oral bioavailability of RG.

Topics: Administration, Oral; Animals; Biological Availability; Blood Glucose; Calorimetry, Differential Scanning; Carbamates; Chromatography, High Pressure Liquid; Diabetes Mellitus, Experimental; Drug Carriers; Drug Stability; Drug Storage; Hypoglycemic Agents; Lipids; Male; Microscopy, Electron, Transmission; Nanoparticles; Particle Size; Piperidines; Rats; Rats, Wistar; Solubility; Surface Properties; X-Ray Diffraction

The purpose of this work was to develop prolonged release binary lipid matrix-based solid lipid nanoparticles (SLN) of repaglinide (RG) for oral intestinal delivery and to improve the bioavailability of RG. SLN were designed by using glycerol monostearate and tristearin as lipid core materials and Pluronic-F68 as stabilizer. SLN were characterised by their particle size, zeta potential, entrapment efficiency, solid-state studies, in vitro drug release, particle surface and storage stability at 30 °C/65% relative humidity for 3 months. Pharmacodynamic (PD) and pharmacokinetic (PK) studies were also performed in diabetes-induced rat. Moreover, an in vitro toxicity study was performed in rat macrophage cells to establish the safety of the prepared SLN. It was observed that binary lipid matrix-based SLN had better drug entrapment, desired release characteristics, spherical shape and maximum storage stability. Pharmacodynamic study indicated that RG delivered through binary SLN significantly reduces blood glucose, blood cholesterol and blood triglycerides level. The area under the curves after oral administration of optimised RG-SLN formulation and RG control were 113.36 ± 3.01 and 08.08 ± 1.98 h/(ng · mL), respectively. The relative bioavailability of RG was enhanced with optimised SLN formulation when compared with RG control. There was a direct correlation found between the plasma drug level (drug concentration) and the peak response (% blood glucose inhibition) in optimised RG-SLN batch. The in vitro toxicity study indicated that the SLN were well tolerated.

Topics: Animals; Biological Availability; Blood Glucose; Carbamates; Cell Survival; Cells, Cultured; Chromatography, High Pressure Liquid; Diabetes Mellitus, Experimental; Drug Carriers; Drug Stability; Hypoglycemic Agents; Lipids; Macrophages, Peritoneal; Male; Microscopy, Electron, Transmission; Nanoparticles; Particle Size; Phase Transition; Piperidines; Rats; Rats, Wistar; Solubility; Surface Properties

The aim of this study was to develop a pH-sensitive chitosan/polyvinyl pyrrolidone (PVP) based controlled drug release system for repaglinide. The hydrogels were synthesised by crosslinking chitosan and PVP blend with glutaraldehyde to form a semi-interpenetrating polymer network (semi-IPN). These semi-IPNs were studied for their content uniformity, swelling index (SI), mucoadhesion, wettability, in vitro release and their release kinetics. The hydrogels showed more than 95% loading of repaglinide. These hydrogels showed high swelling and mucoadhesion under acidic conditions. The swelling was found due to the protonation of a primary amino group on chitosan. In acidic condition chitosan was ionized, and adhesion occurred between the positively charged chitosan and the negatively charged mucus. In the physiological condition less swelling was noticed. In vitro release study revealed that formulation containing chitosan (2% w/v) and PVP (4% w/v) in the ratio of 14:6 w/w showed complete drug release after 12h. Release profile showed that all the formulations followed non-fickian diffusion mechanism (diffusion coupled with swelling). Fourier transform infrared (FTIR) spectroscopic analysis revealed proper crosslinking of polymer and formation of semi-IPN as well as presence of drug in the formulation. Differential scanning calorimetry (DSC) and powder x-ray diffraction (p-XRD) study revealed the presence of repaglinide in crystalline form in the formulations. The surface morphology of semi-IPN was studied before and after dissolution in simulated gastric fluid (SGF, pH 1.2) which indicated generation of open channel-like structure in hydrogel after dissolution. The results of study suggest that semi-IPNs of chitosan/PVP are potent candidates for delivery of repaglinide in acidic environment.

Topics: Adhesiveness; Animals; Calorimetry, Differential Scanning; Carbamates; Chemistry, Pharmaceutical; Chitosan; Cross-Linking Reagents; Crystallography, X-Ray; Delayed-Action Preparations; Diffusion; Drug Carriers; Drug Compounding; Gastric Juice; Glutaral; Hydrogels; Hydrogen-Ion Concentration; Hypoglycemic Agents; Kinetics; Microscopy, Electron, Scanning; Piperidines; Povidone; Powder Diffraction; Rats; Solubility; Spectroscopy, Fourier Transform Infrared; Surface Properties; Technology, Pharmaceutical; Wettability

Meglitinides (repaglinide and nateglinide) are insulin secretagogues used to treat diabetes mellitus. We present a case of hypersensitivity reaction to repaglinide in a 61-year-old man who developed a maculopapular rash 5 days after treatment. Skin prick tests including repaglinide (0.5 g/mL) and patch tests (0.05% in pet and saline) were performed, and the results were negative. A blind oral challenge test with repaglinide was performed and the therapeutic dose was subsequently taken at home every 24 hours for 7 days. The result was positive with a delayed reaction at day 3. A punch biopsy of the skin lesions revealed drug-induced exanthema. The clinical manifestations, the latency period, the reappearance of cutaneous lesions after rechallenge, and the histopathology report of the skin biopsy suggest a type IV mechanism.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Hypersensitivity; Erythema; Exanthema; Humans; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Patch Tests; Phenylalanine; Piperidines

To evaluate the ability of Gelucire 50/13 (an amphiphilic lipid excipient) to act as a stabilizer for lipid nanocarriers such as solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) and to establish the ability of Gelucire 50/13 based lipid nanocarriers to improve oral delivery of hydrophobic drugs using repaglinide (RPG) as a model drug.. The ability of Gelucire 50/13 to nanosize various solid lipids was evaluated. The ability of Gelucire 50/13 to yield NLC was evaluated by using Precirol ATO 5 as a model solid lipid and various liquid lipids (oils). Gelucire 50/13 based NLC (GeluPearl) were evaluated for their ability to improve the efficacy of RPG on oral administration in comparison to RPG tablets. The short term stability of RPG-GeluPearl was evaluated at 25 °C/60% RH.. Gelucire 50/13 could successfully yield SLN and NLC of various solid lipids, demonstrating its potential to act as a novel stabilizer. DSC studies indicated that Gelucire 50/13 interacts with Precirol ATO 5 and this interaction suppresses polymorphic transitions of both the components. RPG-GeluPearl exhibited significantly higher anti-diabetic activity compared to marketed RPG tablets. RPG-GeluPearl demonstrated good colloidal and chemical stability at the end of 1 month.

Topics: Administration, Oral; Animals; Blood Glucose; Calorimetry, Differential Scanning; Carbamates; Diabetes Mellitus, Experimental; Diglycerides; Drug Carriers; Drug Delivery Systems; Drug Stability; Fats; Feasibility Studies; Glucose Tolerance Test; Lipids; Nanoparticles; Nanotechnology; Oils; Particle Size; Piperidines; Rats; Surface-Active Agents

1. In the present study, we investigated the associations of nicotinamide phosphoribosyltransferase (NAMPT)-3186 C/T and -948G/T polymorphisms with the risk of Type 2 diabetes mellitus (T2DM) and their impact on the efficacy of repaglinide in Chinese Han T2DM patients. 2. In all, 170 patients with T2DM and 129 healthy controls were genotyped for NAMPT-948G>T and -3186C>T polymorphisms. Thirty-five patients with different NAMPT -3186 C/T genotypes and the same organic anion-transporting polypeptide 1B1 (OATP1B1521) T/C genotype were randomly selected to undergo 8 weeks preprandial repaglinide treatment (1 mg, three times daily). Serum fasting plasma glucose (FPG), post-prandial plasma glucose (PPG), glycated haemoglobin (HbAlc), fasting serum insulin (FINS), post-prandial serum insulin (PINS), triglyceride (TG), total cholesterol (CHO), homeostasis model assessment of insulin resistance (HOMA-IR), low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol (HDL-C) were determined before and after repaglinide treatment. 3. After repaglinide treatment for 8 consecutive weeks, there were significantly decreases in PFG, PPG, HbAlc, CHO and LDL-C, and increases in FINS, HDL-C and the HDL-C : LDL-C ratio, in T2DM patients. The elevated PINS value in patients with CT genotypes was significantly lower than that in patients with the CC and TT genotypes (P < 0.05) and there were significant differences in CHO between patients with the CT genotype and the CC or TT genotype (P < 0.05). 4. The data suggest that the NAMPT -3186C>T polymorphism is significantly associated with plasma levels of PINS and CHO in Chinese T2DM patients with repaglinide monotherapy.

Topics: Adult; Aged; Alleles; Asian People; Carbamates; Cholesterol; Control Groups; Diabetes Mellitus, Type 2; Female; Genetic Predisposition to Disease; Genotype; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Nicotinamide Phosphoribosyltransferase; Piperidines; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Treatment Outcome

The use of retroviral drugs in the treatment of infection by human immunodeficiency virus (HIV) is associated, especially for first generations, with side effects such as lipodystrophy, fatty liver and insulin resistance, which may trigger secondary diabetes or worsen existing diabetes. The use of Glucagon-Like Peptide-1 in obese patients with type 2 diabetes on HIV retroviral as an alternative to insulin therapy is not documented; we report the case of a 47-year-old treated with exenatide when insulin was discontinued. During the first year of treatment, exenatide, in combination with metformin and repaglinide, led to a weight loss of 14 kg and fat mass and waist circumference were respectively reduced from 31 to 25.5% and from 114 to 103 cm. Homeostatic model assessment (HOMA) was used to calculate β-cell secretion which increased from 50 to 78% and insulin sensitivity which increased from 28 to 51%, reflecting a decrease in HbA(1c) by 1.9%. Exenatide may be a new therapeutic option for HIV-infected type 2 diabetes patients undergoing retroviral therapy.

Topics: Adipose Tissue; Antiretroviral Therapy, Highly Active; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Exenatide; HIV Infections; Humans; Hypoglycemic Agents; Insulin Resistance; Insulin-Secreting Cells; Male; Metformin; Middle Aged; Peptides; Piperidines; Venoms; Waist Circumference; Weight Loss

Understanding the potential for cytochrome P450 (P450)-mediated drug-drug interactions is a critical step in the drug discovery process. Although in vitro studies with CYP3A4, CYP2C9, and CYP2C19 have suggested the presence of multiple binding regions within the P450 active site based on probe substrate-dependent inhibition profiles, similar studies have not been performed with CYP2C8. The ability to understand CYP2C8 probe substrate sensitivity will enable appropriate in vitro and in vivo probe selection. To characterize the potential for probe substrate-dependent inhibition with CYP2C8, the inhibition potency of 22 known inhibitors of CYP2C8 were measured in vitro using four clinically relevant CYP2C8 probe substrates (montelukast, paclitaxel, repaglinide, and rosiglitazone) and amodiaquine. Repaglinide exhibited the highest sensitivity to inhibition in vitro. In vitro phenotyping indicated that montelukast is an appropriate probe for CYP2C8 inhibition studies. The in vivo sensitivities of the CYP2C8 probe substrates cerivastatin, fluvastatin, montelukast, pioglitazone, and rosiglitazone were determined in relation to repaglinide on the basis of clinical drug-drug interaction (DDI) data. Repaglinide exhibited the highest sensitivity in vivo, followed by cerivastatin, montelukast, and pioglitazone. Finally, the magnitude of in vivo CYP2C8 DDI caused by gemfibrozil-1-O-β-glucuronide was predicted. Comparisons of the predictions with clinical data coupled with the potential liabilities of other CYP2C8 probes suggest that montelukast is an appropriate CYP2C8 probe substrate to use for the in vivo situation.

Topics: Acetates; Amodiaquine; Aryl Hydrocarbon Hydroxylases; Binding Sites; Carbamates; Cyclopropanes; Cytochrome P-450 CYP2C8; Drug Interactions; Humans; Microsomes, Liver; Paclitaxel; Piperidines; Quinolines; Rosiglitazone; Sensitivity and Specificity; Substrate Specificity; Sulfides; Thiazolidinediones

Our aim was to investigate the placental transfer of repaglinide by ex vivo placental perfusion experiment. In addition, the involvement of the active organic anion transporters (OATP1B1, OATP1B3 and OATP2B1) was studied by assessing the single nucleotide polymorphisms (SNPs) in genes (SLCO1B1, SLCO1B3 and SLCO2B1) encoding OATPs.. Fifteen placentas were obtained after delivery and a 2-h non-recirculating perfusion of a single placental cotyledon was performed to study maternal-to-fetal and fetal-to-maternal transport of repaglinide by using antipyrine as a reference of passive-diffusion transfer compound. Genotyping was performed for all placentas.. Maternal-to-fetal transfer of repaglinide and antipyrine were 1.5% and 13.2%, respectively, and fetal-to-maternal transfers were 6.7% and 40.3%, respectively. Fetal-to-maternal transfer of repaglinide was statistically significantly higher than maternal-to-fetal transfer (P<0.0001). The number of placentas was not sufficient for proper statistical analysis, but the fetal-to-maternal transfer seemed to be affected by the SLCO1B3 polymorphism.. The placental transfer of repaglinide from mother to fetus was low. Since a higher transfer rate of repaglinide was observed in fetal-to-maternal than maternal-to-fetal direction, active transport by OATP-transporters may be an important factor in fetal exposure to repaglinide.

Topics: Carbamates; Chromatography, Liquid; Female; Humans; Hypoglycemic Agents; In Vitro Techniques; Maternal-Fetal Exchange; Organic Anion Transporters; Perfusion; Piperidines; Placenta; Polymorphism, Single Nucleotide; Pregnancy; Tandem Mass Spectrometry

Repaglinide is an FDA-approved treatment for type 2 diabetes mellitus. The anti-inflammatory effect of repaglinide in the absence of diabetes has not been reported previously. It is the objective of this set of studies to investigate the potential anti-inflammatory effects of repaglinide.. The in vivo anti-inflammatory effects of repaglinide were studied in two different models of delay type hyperreactivity (DTH) response induced by sheep red blood cells (sRBC) and 2,5'-dinitrofluorobenzene (DNFB), and in two different rodent models of lipopolysaccharide (LPS) challenge.. In mice systemically sensitized with sRBC, which subsequently received a local injection of sRBC in the footpad, local swelling occurred within 24 h after challenge. Repaglinide was efficacious in attenuating this response. In an orthogonal DTH model using DNFB as the antigen, the animals received topical sensitization with DNFB on their shaved backs, followed by topical challenge on the left ears. Repaglinide efficaciously downregulated the resulting ear swelling response. In mice challenged systemically or intratracheally with LPS, repaglinide significantly decreased serum tumor necrosis factor α level and bronchial alveolar lavage fluid MCP-1 levels, respectively.. This set of data suggests novel anti-inflammatory effects of repaglinide in nondiabetic animals. However, the high dose required for an efficacious effect would make this application impractical in the clinic.

Topics: Animals; Anti-Inflammatory Agents; Carbamates; Chemokine CCL2; Dinitrofluorobenzene; Ear; Erythrocytes; Foot; Hypersensitivity, Delayed; Immunologic Factors; Lipopolysaccharides; Male; Mice; Mice, Inbred ICR; Piperidines; Pneumonia; Sheep; Tumor Necrosis Factor-alpha

Biological pathways are seen as highly critical in our understanding of the mechanism of biological functions. To collect information about pathways, manual curation has been the most popular method. However, pathway annotation is regarded as heavily time-consuming, as it requires expert curators to identify and collect information from different sources. Even with the pieces of biological facts and interactions collected from various sources, curators have to apply their biological knowledge to arrange the acquired interactions in such a way that together they perform a common biological function as a pathway. In this paper, we propose a novel approach for automated pathway synthesis that acquires facts from hand-curated knowledge bases. To comprehend the incompleteness of the knowledge bases, our approach also obtains facts through automated extraction from Medline abstracts. An essential component of our approach is to apply logical reasoning to the acquired facts based on the biological knowledge about pathways. By representing such biological knowledge, the reasoning component is capable of assigning ordering to the acquired facts and interactions that is necessary for pathway synthesis. We demonstrate the feasibility of our approach with the development of a system that synthesizes pharmacokinetic pathways. We evaluate our approach by reconstructing the existing pharmacokinetic pathways available in PharmGKB. Our results show that not only that our approach is capable of synthesizing these pathways but also uncovering information that is not available in the manually annotated pathways.

Topics: Artificial Intelligence; Carbamates; Computational Biology; Humans; Knowledge Bases; MEDLINE; Metabolic Networks and Pathways; Models, Biological; Pharmacokinetics; Piperidines; Pravastatin; Synthetic Biology

Topics: Administration, Oral; Biguanides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Drug Combinations; Drug Therapy, Combination; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines; Sulfonylurea Compounds

To estimate population pharmacokinetic parameters of repaglinide in 121 healthy Malaysian volunteers.. Each subject received 4 mg of oral repaglinide. Six blood samples were taken per individual (0, 30, 60, 120, 180 and 240 min) for repaglinide's serum concentration determination by using high-performance liquid chromatography. The parametric Iterative Two-Stage Bayesian Population Model (it2b) program followed by the Non-Parametric Adaptive Grid (npag) program was used to determine a population pharmacokinetic modelling of repaglinide.. Using the npag program, the mean elimination rate constant (k(el)) of repaglinide was 0.58 +/- 0.27 h and the volume of distribution (V(d)) was 23.09 +/- 9.19 L/h.. In this first report, specifically on the population pharmacokinetic modelling of repaglinide, the data generated should help us to better understand appropriate dosage-regimens for the drug.

Topics: Adolescent; Adult; Algorithms; Body Mass Index; Carbamates; Female; Half-Life; Humans; Hypoglycemic Agents; Male; Metabolic Clearance Rate; Middle Aged; Models, Biological; Piperidines; Young Adult

To report a case of clinically significant hypoglycemia attributed to the concomitant use of trimethoprim/sulfamethoxazole (TMP/SMX) and repaglinide by a diabetic patient.. A 76-year-old diabetic patient with impaired renal function and no history of hypoglycemia was receiving treatment with repaglinide 1 mg 3 times daily. Five days after TMP/SMX therapy was started for a urinary tract infection, the man developed symptomatic hypoglycemia. Repaglinide and TMP/SMX were stopped and intravenous D-glucose was administered to normalize glucose levels. Repaglinide, but not TMP/SMX, was reintroduced 5 days later and no other hypoglycemic episode occurred. Objective causality assessments revealed that the interaction was probable (World Health Organization-Uppsala Monitoring Centre) or possible (Horn Drug Interaction Probability Scale).. This interaction between TMP/SMX and repaglinide was predictable according to available pharmacokinetic data in healthy subjects. Trimethoprim induced CYP2C8 inhibition, thus increasing the plasma concentration of repaglinide. This interaction is mentioned in the repaglinide product information. To our knowledge, however, no case of symptomatic hypoglycemia associated with a combination of repaglinide and trimethoprim has been described before. This discrepancy may be explained by the subtherapeutic dosage used in the pharmacokinetic study. Moreover, our patient had impaired renal function, which may have led to trimethoprim accumulation and potentiated its interaction with repaglinide. A direct lowering of blood glucose levels due to sulfamethoxazole, also potentiated by renal failure, could also be involved in triggering hypoglycemia.. This interaction between TMP/SMX and repaglinide may have involved inhibition of CYP2C8 by trimethoprim. Clinicians should be aware that this association may lead to symptomatic hypoglycemia, particularly in patients with renal dysfunction.

Topics: Aged; Anti-Infective Agents, Urinary; Blood Glucose; Carbamates; Diabetes Complications; Diabetes Mellitus; Diabetic Neuropathies; Drug Interactions; Energy Intake; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Piperidines; Trimethoprim, Sulfamethoxazole Drug Combination; Urinary Tract Infections

This study is an extension of the previous enhancement of dissolution properties of repaglinide using liquisolid compacts. The development and validation of a highperformance liquid chromatography (HPLC) assay for the determination of repaglinide concentration in rabbit plasma for pharmacokinetic studies is described. Repaglinide optimizing formula was orally administered to rabbits and blood samples were used to determine the pharmacokinetic parameters of repaglinide, which were compared to pharmacokinetic parameters of marketed tablets (Novonorm 2 mg). Also, to investigate the biological activity of this new formula, in comparison with the commercial product, oral glucose tolerance tests (OGTT), area under the curve and insulin levels were studied. Moreover, we studied the efficacy and safety of this new formula in several potencies (0.5, 1, and 2 mg) and blood glucose, insulin, kidney and liver functions. The relative bioavailability of repaglinide from its liquisolid compact formula was found to be increased significantly in comparison to that of the marketed tablet. In regard to urea and creatinine, no significant change was recorded after the administration of the commercial and the three potencies of the new formulation compared with the control group. Similarly, in liver function tests (serum glutamic pyruvic transaminase, SGPT), there were no changes observed in its level. Regarding insulin levels, the commercial formula increased insulin levels insignificantly (3.52% change) while the new formula increased the insulin level significantly with a percent change of 37.6%. The results of the glucose tolerance test showed that the blood glucose level was decreased significantly after the commercial drug (percent change, 18.1%) while in groups treated with the new formulation the decrease was highly significant (p < 0.01) with a percent change of 29.98%. The change in area under the curve for blood glucose was significantly higher in the commercial drug plus glucose load than in the new formulation plus glucose load group (p < 0.05) in the periods of 30-45 min and 45-60 min. Furthermore, the new repaglinide formulation significantly decreased blood glucose levels more than the commercial formula.

Topics: Administration, Oral; Animals; Area Under Curve; Biological Availability; Blood Glucose; Carbamates; Chromatography, High Pressure Liquid; Dosage Forms; Drug Compounding; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Insulin; Male; Piperidines; Rabbits; Random Allocation; Reproducibility of Results; Sensitivity and Specificity

To investigate a potential association between SNP rs10494366 in the neural nitric oxide synthase adaptor protein (NOS1AP) and efficacy of repaglinide (an insulin secretagogue) in newly diagnosed Shanghai Chinese type 2 diabetes patients.. A total of 104 newly diagnosed type 2 diabetes patients (69 men, 35 women) were recruited and treated with repaglinide for 24 weeks. Anthropometric measurements, clinical laboratory tests were obtained at baseline and after 24-week treatment. Genotyping was performed by sequencing.. The baseline value of BMI, HOMA-IR, HOMA-B, and fasting insulin level were significantly different between GG, GT, and TT genotypes (P=0.024, 0.030, 0.005, and 0.007, respectively). Carriers of TT genotype were in significant insulin resistance at baseline. After 24-week repaglinide monotherapy, the Delta value of fasting insulin (P=0.019) and HOMA-IR (P=0.011) were significantly different. TT carriers had the least insulin resistance after treatment. The mixed model analysis showed that the variation had an interaction effect with repaglinide treatment only on HOMA-IR (P=0.013).. A common variant in rs10494366 is associated with repaglinide monotherapy efficacy on insulin resistance in newly diagnosed Shanghai Chinese type 2 diabetes patients.

Topics: Adaptor Proteins, Signal Transducing; Carbamates; China; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Insulin Resistance; Male; Middle Aged; Piperidines; Polymorphism, Single Nucleotide

To investigate the effects of CYP3A4 and CYP2C8 enzymes on repaglinide's pharmacokinetics in healthy Malaysian subjects.. Subjects (n = 121) received oral repaglinide (4 mg). Blood samples were taken at 0, 30, 60, 120, 180 and 240 min and serum concentrations of repaglinide were determined using high-performance liquid chromatography. Subjects were also genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for CYP3A4*4, *5 and*18 and by an allele-specific multiplex PCR for CYP2C8*2, *3, *4 and *5 alleles.. The allele frequencies of CYP2C8*1, *2, *3, *4 and *5 were 95.04, 0.40, 0.40, 0 and 4.13%, respectively. The frequencies of the CYP3A4*1, *4, *5 and *18 alleles were 97.93, 0, 0 and 2.07%, respectively. CYP2C8 and CYP3A4 genotypes were not significantly associated with repaglinide's blood glucose-lowering effect. However, the CYP3A4 genotype significantly influenced some of repaglinide's pharmacokinetics, where the mean elimination rate constant was 44.0% lower (p = 0.04) and the mean half-life was 33.8% higher (p = 0.04) in subjects with the CYP3A4*1/*18 genotype as compared to those with the normal CYP3A4*1/*1 genotype. This result confirms that CYP3A4 plays a large role in metabolizing repaglinide.. Genetic polymorphisms of CYP3A4, specifically CYP3A4*18, play a major role in contributing to the interindividual variability in repaglinide's pharmacokinetics.

Topics: Adolescent; Adult; Aryl Hydrocarbon Hydroxylases; Asian People; Carbamates; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Genotype; Humans; Hypoglycemic Agents; Middle Aged; Piperidines; Polymorphism, Genetic; Young Adult

To investigate whether the insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) rs1470579 and rs4402960 polymorphisms are associated with the development of type 2 diabetes mellitus (T2DM) and the repaglinide therapeutic efficacy in Chinese T2DM patients.. A case-control study of a total of 350 patients with T2DM and 207 healthy volunteers was conducted to identify their genotypes for the IGF2BP2 rs1470579 and rs4402960 polymorphisms using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Forty-two patients were randomly selected to undergo an 8-week repaglinide treatment (3 mg/d). Fasting plasma glucose (FPG), postprandial plasma glucose (PPG), glycated hemoglobin (HbAlc), fasting serum insulin (FINS), postprandial serum insulin (PINS), homeostasis model assessment for insulin resistance (HOMA-IR), serum triglyceride, total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-c), and high-density lipoprotein-cholesterol (HDL-c) were determined before and after repaglinide treatment.. The frequencies of the IGF2BP2 rs1470579 C allele and the rs4402960 T allele were higher in T2DM patients than in healthy controls (P<0.05 and P<0.001, respectively). The effects of the repaglinide treatment on FPG (P<0.05) and PPG (P<0.05) were reduced in patients with the rs1470579 AC+CC genotypes compared with AA genotype carriers. Patients with the rs4402960 GT+TT genotypes exhibited an enhanced effect of repaglinide treatment on PINS (P<0.01) compared with GG genotype subjects.. The IGF2BP2 rs1470579 and rs4402960 polymorphisms may be associated with the development of T2DM, and these polymorphisms may affect the therapeutic efficacy of repaglinide in Chinese T2DM patients.

Topics: Adult; Aged; Asian People; Carbamates; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Gene Frequency; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Piperidines; Polymorphism, Genetic; Risk Factors; RNA-Binding Proteins

With the objective to achieve prolonged drug release, especially for the treatment of diabetes mellitus, and thereby to reduce the side effects of administration of conventional dosage form, repaglinide loaded PMMA nanoparticles have been formulated. These nanoparticles have been developed by solvent evaporation method and were subjected to various studies for characterization including photon correlation spectroscopy (PCS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). These studies favorably revealed that the mean particle diameter of optimized formulation was 108.3nm and had spherical morphology with amorphous nature. Moreover, these particles were also subjected to Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) for compatibility analysis between drug and polymer. The results were positive and showed that, there were no interaction between drug and polymer. The optimized formulation demonstrated favorable in vitro prolonged release characteristics. Experimental in vitro release data were substituted with available mathematical models to establish the mechanism of release of repaglinide and was found to follow zero order, diffusion and erosion mechanisms. The in vivo toxicity study in albino rats showed no significant change in biochemical and pathological examinations. Hence, the designed system could possibly be advantageous in terms of prolonged release, to achieve reduced dose frequency and improve patient compliance of repaglinide.

Topics: Animals; Calorimetry, Differential Scanning; Carbamates; Chemistry, Pharmaceutical; Delayed-Action Preparations; Drug Carriers; Drug Compounding; Female; Hypoglycemic Agents; Kinetics; Male; Microscopy, Electron, Scanning; Models, Chemical; Nanoparticles; Nanotechnology; Particle Size; Piperidines; Polymethyl Methacrylate; Rats; Rats, Wistar; Solubility; Spectroscopy, Fourier Transform Infrared; Technology, Pharmaceutical; Thermogravimetry; X-Ray Diffraction

Genome-wide association studies (GWASs) identified that SLC30A8 genetic polymorphism was a risk of type 2 diabetes mellitus (T2DM) in several populations. This study aimed to investigate whether the SLC30A8 rs13266634 and rs16889462 polymorphisms were associated with T2DM susceptibility and repaglinide therapeutic efficacy in Chinese T2DM patients.. We conducted a case-control study of 443 T2DM patients and 229 healthy volunteers to identify SLC30A8 rs13266634 and rs16889462 genotypes by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Forty-eight patients were randomly selected and underwent an 8-week repaglinide treatment (3 mg/d). Fasting plasma glucose (FPG), postprandial plasma glucose (PPG), glycated hemoglobin (HbAlc), fasting serum insulin (FINS), postprandial serum insulin (PINS), homeostasis model assessment for insulin resistance (HOMA-IR), serum triglyceride, total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-c) and high-density lipoprotein-cholesterol (HDL-c) were determined before and after repaglinide treatment.. SLC30A8 rs13266634 risk C allele frequency was higher in T2DM patients than in healthy controls (P < 0.05). There was a better repaglinide response on FINS (P < 0.05) and PINS (P < 0.01) in patients with rs13266634 CT+TT genotypes compared with CC genotype carriers. Patients with rs16889462 GA genotype showed an enhanced repaglinide efficacy on FPG (P < 0.01), PPG (P < 0.01) and HbAlc (P < 0.05) compared with GG genotype individuals.. SLC30A8 rs13266634 and rs16889462 polymorphisms were associated with repaglinide therapeutic efficacy in Chinese T2DM patients.

Topics: Adult; Aged; Base Sequence; Carbamates; Case-Control Studies; Cation Transport Proteins; China; Diabetes Mellitus, Type 2; DNA Primers; Female; Gene Frequency; Genome-Wide Association Study; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Polymerase Chain Reaction; Polymorphism, Genetic; Zinc Transporter 8

the time for 1.0 mm ST-segment depression (T-1.0mm) adopted to characterize ischemic preconditioning (IPC) in sequential exercise tests is consistent and reproducible; however, it has several limitations.. to apply an electrocardiographic score of myocardial ischemia in sequential exercise tests, comparing it to the conventional T-1.0 mm index.. sixty one patients with mean age of 62.2 ± 7.5 years were evaluated; 86.9% were males. A total of 151 tests were analyzed, 116 of which were from patients who completed two assessment phases. The first phase comprised two sequential exercise tests for the documentation of IPC; the second phase, initiated one week later, comprised two more tests carried out under the effect of repaglinide. Two observers who were blind to the tests applied the score.. Perfect inter and intraobserver agreement was found (Kendall tau-b = 0.96, p < 0.0001, and Kendall tau-b = 0.98, p < 0.0001, respectively). Values of sensitivity and specificity, negative predictive value, positive predictive value and accuracy were 72.41%, 89.29%, 75.8%, 87.5% and 81.0%, respectively.. the ischemic score is a consistent and reproducible method for the documentation of IPC, and is a feasible alternative to T-1.0 mm.

Topics: Carbamates; Diabetes Mellitus; Double-Blind Method; Electrocardiography; Ergometry; Female; Humans; Hypoglycemic Agents; Ischemic Preconditioning; Male; Middle Aged; Myocardial Ischemia; Observer Variation; Piperidines; Predictive Value of Tests

A simple, fast and sensitive HPLC method employing dual-channel coulometric detection for the determination of repaglinide in human plasma is presented. The assay involved extraction of repaglinide by ethyl acetate and isocratic reversed-phase liquid chromatography with dual-channel coulometric detection. The mobile phase composition was 50mM disodium hydrogen phosphate/acetonitrile (60:40, v/v), pH of the mobile phase 7.5 set up with phosphoric acid. For all analyses, the first cell working potential was +380mV, the second was +750mV (vs. Pd/H(2)). Calibration curve was linear over the concentration range of 5-500nmolL(-1). Rosiglitazone was used as an internal standard. The limit of detection (LOD) was established at 2.8nmolL(-1), and the lower limit of quantification (LLOQ) at 8.5nmolL(-1). The developed method was applied to human plasma samples spiked with repaglinide at therapeutical concentrations. It was confirmed that the method is suitable for pharmacokinetic studies or therapeutic monitoring.

Topics: Carbamates; Chromatography, High Pressure Liquid; Colorimetry; Electrochemical Techniques; Humans; Hydrogen-Ion Concentration; Hypoglycemic Agents; Linear Models; Piperidines; Reproducibility of Results; Rosiglitazone; Sensitivity and Specificity; Thiazolidinediones

The present investigation describes organic volatile solvent-free approach for the single step fabrication of Eudragit nanoparticles. The solubility of various grades of Eudragit viz. Eudragit L100-55, Eudragit L100, Eudragit S100, Eudragit EPO, Eudragit RSPO and Eudragit RLPO in Labrasol (Caprylocaproyl macrogol-8 glycerides) was determined. We observed that Labrasol has the ability to solubilize various cationic Eudragits such as Eudragit RSPO, Eudragit RLPO and Eudragit EPO at a concentration as high as 200 mg/ml. We also evaluated the ability of Labrasol to act as a nanoparticle stabilizer due to its amphiphilic nature and high HLB of 14. It was observed that Eudragit EPO, Eudragit RSPO and Eudragit RLPO nanoparticles of size 110-150 nm could be easily fabricated using Labrasol as a solubilizer and nanoparticle stabilizer. Transmission electron microscopy was carried out to confirm the size and morphology of the nanoparticles. We could encapsulate hydrophobic drugs such as repaglinide and triclosan in the Eudragit RLPO nanoparticles as Labrasol also had the ability to solubilize these hydrophobic drugs. The ability of Eudragit RSPO and RLPO nanoparticles to condense plasmid DNA was also established. This is the first report that demonstrates the polymer solubilizing potential of Labrasol.

Topics: Anti-Infective Agents, Local; Carbamates; DNA; Drug Compounding; Excipients; Glycerides; Hypoglycemic Agents; Microscopy, Electron, Transmission; Nanoparticles; Organic Chemicals; Particle Size; Piperidines; Plasmids; Polymethacrylic Acids; Solvents; Triclosan

To further explore the mechanism underlying the interaction between repaglinide and gemfibrozil, alone or in combination with itraconazole.. Repaglinide metabolism was assessed in vitro (human liver subcellular fractions, fresh human hepatocytes, and recombinant enzymes) and the resulting incubates were analyzed, by liquid chromatography-mass spectrometry (LC-MS) and radioactivity counting, to identify and quantify the different metabolites therein. Chemical inhibitors, in addition to a trapping agent, were also employed to elucidate the importance of each metabolic pathway. Finally, a panel of human liver microsomes (genotyped for UGT1A1*28 allele status) was used to determine the importance of UGT1A1 in the direct glucuronidation of repaglinide.. The results of the present study demonstrate that repaglinide can undergo direct glucuronidation, a pathway that can possibly contribute to the interaction with gemfibrozil. For example, [³H]-repaglinide formed glucuronide and oxidative metabolites (M2 and M4) when incubated with primary human hepatocytes. Gemfibrozil effectively inhibited (∼78%) both glucuronide and M4 formation, but had a minor effect on M2 formation. Concomitantly, the overall turnover of repaglinide was also inhibited (∼80%), and was completely abolished when gemfibrozil was co-incubated with itraconazole. These observations are in qualitative agreement with the in vivo findings. UGT1A1 plays a significant role in the glucuronidation of repaglinide. In addition, gemfibrozil and its glucuronide inhibit repaglinide glucuronidation and the inhibition by gemfibrozil glucuronide is time-dependent.. Inhibition of UGT enzymes, especially UGT1A1, by gemfibrozil and its glucuronide is an additional mechanism to consider when rationalizing the interaction between repaglinide and gemfibrozil.

Topics: Biotransformation; Carbamates; Cells, Cultured; Dose-Response Relationship, Drug; Drug Interactions; Gemfibrozil; Glucuronides; Glucuronosyltransferase; Hepatocytes; Humans; Hypoglycemic Agents; Hypolipidemic Agents; Itraconazole; Microsomes, Liver; Piperidines

To study the effect of different types of lipid on the entrapment efficiency (EE) and physical stability of repaglinide (RG)-loaded solid lipid nanoparticles (SLNs). RG-loaded SLNs were prepared by modified solvent injection method using stearic acid (RSA), glycerol monosteratae (RGM), glyceryl behenate (RGB) and tristearin (RTS). Poloxamer F68 was used as a stabilizer.. SLNs were characterized by particle size, zeta-potential, EE, in vitro release, solid-state properties (differential scanning calorimetry, transmission electron microscopy and electron diffraction) and stability at 30 degrees C/65% relative humidity for 3 months. The mean particle size and zeta-potential of RG-loaded SLNs prepared with different lipids in varying concentrations ranged from 150 to 355 nm and -21.04 +/- 3.10 to -30.54 +/- 2.76 mV, respectively.. EE was found to vary with lipids in the following order: RSA < RGM < RGB < RTS. Tristearin-prepared SLNs showed a significant prolonged drug release up to 24 h. Differential scanning calorimetry and electron diffraction microphotograph results indicated that RG entrapped in the SLNs existed in an amorphous or molecular state. SLNs prepared with stearic acid, glycerol monostearate and glyceryl behenate after storage showed significant increases in particle size, polydispersity index and EE. The SLNs prepared with tristearin were stable.

Topics: Administration, Oral; Calorimetry, Differential Scanning; Carbamates; Chemistry, Pharmaceutical; Delayed-Action Preparations; Drug Carriers; Drug Compounding; Drug Stability; Excipients; Fatty Acids; Glycerides; Humidity; Hypoglycemic Agents; Kinetics; Lipids; Microscopy, Electron, Transmission; Nanoparticles; Nanotechnology; Piperidines; Poloxamer; Solubility; Stearic Acids; Technology, Pharmaceutical; Temperature; Triglycerides

Aim of this prospective study is to evaluate the effect of repaglinide t.i.d. (three times a day) plus single-dose insulin glargine regimen in low-risk type 2 diabetic patients during Ramadan fasting. Participants had been taking the regimen for at least 3 months. Patients with a history of diabetic coma, severe hypoglycemic crisis or repeating attacks of hypoglycemia were excluded. Hypoglycemic unawareness, kidney or liver disease or HbA1c over 8% were also accepted as exclusion criteria. Eleven patients who insisted on this worship and eight non-fasting cases were involved. All were told to make home-glucose-monitorisation weekly and report any hypoglycemic event throughout Ramadan. Fasting blood glucose (FBG), post-prandial blood glucose (PBG) and fructosamine levels, body weights and blood pressures were recorded just before and after Ramadan. Seven patients in each group concluded the follow-up. Any significant change was detected in the parameters in either groups (P>0.05). Glucose control remained unchanged; fructosamine 318.14+/-65.38 versus 317.28+/-52.80 mmol/L in fasting group, 290.71+/-38.48 versus 290+/-38.56 mmol/L in non-fasting group. None of them exhibited either a major or a minor hypoglycemic event. The results of this pilot study indicated that repaglinide t.i.d. plus single-dose insulin glargine regimen was safe for low-risk type 2 diabetic patients who insisted on fasting during Ramadan.

Topics: Adult; Aged; Blood Glucose; Blood Glucose Self-Monitoring; Blood Pressure; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Fasting; Female; Fructosamine; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Glargine; Insulin, Long-Acting; Islam; Male; Middle Aged; Patient Selection; Piperidines; Risk Assessment; Safety; Turkey

Hypoglycaemia is an acute complication associated with intensive treatment of patients with diabetes mellitus. This complication poses a major challenge in diabetes management. Furthermore, severe hypoglycaemia may be life threatening. Although hypoglycaemia is more often associated with insulin treatment, oral hypoglycaemic agents have the potential to trigger hypoglycaemia.. The aim of this study was to quantify the incidence of hypoglycaemic events and to describe the pattern of these incident events during the first 9 months of treatment with four oral antidiabetic drugs, rosiglitazone, pioglitazone, nateglinide and repaglinide, prescribed in general practice in England.. We used data collected for prescription-event monitoring (PEM) studies of rosiglitazone, pioglitazone, nateglinide and repaglinide. PEM is an observational, non-interventional, incept cohort study. Observation time for each patient and incidence rate (IR) per 1000 patient-years of treatment for hypoglycaemia was calculated for each drug cohort. Smoothed hazard estimates were plotted over time. Case/non-case analysis was performed to describe and compare patients who had at least one hypoglycaemic event in the first 9 months of treatment with those who did not.. The total number of patients included in the analysis was 14,373, 12,768, 4,549 and 5,727 in rosiglitazone, pioglitazone, nateglinide and repaglinide cohorts, respectively. From these, 276 patients experienced at least one episode of hypoglycaemia. The IR was between 50% and 100% higher in patients receiving treatment with meglitinides compared with those treated with the thiazolidinediones (TZDs) [IR = 9.94, 9.64, 15.71 and 20.32 per 1,000 patient-years for rosiglitazone, pioglitazone, nateglinide and repaglinide, respectively]. The plot of the hazard function and the estimated shape parameter from the Weibull regression model showed that pioglitazone, nateglinide and repaglinide had non-constant (decreasing) hazards over time, whereas the hazard for rosiglitazone-treated patients was approximately constant over time. Nateglinide and repaglinide had similar shape hazard function, indicating a significantly higher number of hypoglycaemic episodes shortly after starting treatment. For women treated with TZDs, hypoglycaemia was reported more frequently than for men.. This analysis shows that the frequency of reported hypoglycaemia within the study cohorts was relatively low. The rates of hypoglycaemia were not equal between drug classes. Treatment with nateglinide or repaglinide was characterized by a higher incidence of hypoglycaemia at the beginning of treatment. Further investigation is necessary to assess whether women treated with TZDs are more prone to hypoglycaemia than men. Findings from this study should be taken into account with other clinical and pharmacoepidemiological studies.

Topics: Administration, Oral; Adult; Adverse Drug Reaction Reporting Systems; Carbamates; Cohort Studies; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Monitoring; Drug Prescriptions; Female; Humans; Hypoglycemia; Hypoglycemic Agents; Incidence; Male; Middle Aged; Nateglinide; Phenylalanine; Pioglitazone; Piperidines; Rosiglitazone; Sex Factors; Thiazolidinediones

Topics: Administration, Oral; Carbamates; Diabetes Mellitus, Type 2; Drug Combinations; Drug Interactions; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Metformin; Piperidines; Tablets; Treatment Outcome

The subject matter of this case report is "sudden deterioration" of glycemic control in a thus far well-complying patient with type 2 diabetes. It describes possible impacts of glucometer technical failure associated with other unfavorable circumstances. An error in displaying glycemia was discovered when analyzing data from glucometer in a computer using software (DIABASS PRO, Mediaspect GmbH, Konstanz, Germany) for data evaluation, and other possible complications (especially hypoglycemia episodes) resulting from inadequate treatment correction were thus prevented.

Topics: Blood Glucose; Blood Glucose Self-Monitoring; Carbamates; Computers; Diabetes Mellitus, Type 2; Equipment Failure; Fasting; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Metformin; Middle Aged; Piperidines; Self Care; Software

The pathological development and the drug intervention of type 2 diabetes mellitus (T2DM) involve altered expression of downstream low molecular weight metabolites including lipids and amino acids, and carbohydrates such as glucose. Currently, a small number of markers used for clinical assessment of T2DM treatment may be insufficient to reflect global variations in pathophysiology. In this study, a metabonomic study was performed to determine metabolic variations associated with T2DM and the drug treatments on 74 patients who were newly diagnosed with T2DM and received a 48 week treatment of a single drug, repaglinide, metformin or rosiglitazone. Fasting overnight and 2 h postprandial blood serum of patients were collected at 24 and 48 weeks to monitor the biochemical indices (FPG, 2hPG, HbA1c, etc.). Gas chromatography/mass spectrometer coupled with multivariate statistical analysis was used to identify the alteration of global serum metabolites associated with T2DM as compared to healthy controls and responses to drug treatment. Significantly altered serum metabolites in diabetic subjects include increased valine, maltose, glutamate, urate, butanoate and long-chain fatty acid (C16:0, C18:1, C18:0, octadecanoate and arachidonate), and decreased glucuronolactone, lysine and lactate. All of the three treatments were able to down-regulate the high level of glutamate to a lower level in serum of T2DM patients, but rosiglitazone treatment was able to reverse more abnormal levels of metabolites, such as valine, lysine, glucuronolactone, C16:0, C18:1, urate, and octadecanoate, suggesting that it is more efficient to alter the metabolism of T2DM patients than the other two drugs.

Topics: Carbamates; Diabetes Mellitus, Type 2; Gas Chromatography-Mass Spectrometry; Humans; Hypoglycemic Agents; Lactic Acid; Lysine; Metabolomics; Metformin; Piperidines; Rosiglitazone; Thiazolidinediones; Uric Acid; Valine

Topics: Aged, 80 and over; Carbamates; Gastrointestinal Agents; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Octreotide; Piperidines

The lungs are involved in diabetes in the cause of the complex phenomena diabetes generates. In the present study, hyperglycemia inhibited pulmonary antioxidants, including superoxide dismutase, catalase, glutathione peroxidase, and glutathione. These effects were accompanied by significant elevation of lipid peroxidation, total nitrites, and nitrotyrosine levels. The study investigated the effects of 2 oral antidiabetics, pioglitazone and repaglinide, on the mentioned parameters. It is concluded that pioglitazone exerts protective effect in the lung by inhibiting nitrosative stress and normalizing the nitrites and nitrotyrosine levels. Administration of repaglinide prevents oxidative and, to a smaller extent, nitrosative changes.

Topics: Administration, Oral; Animals; Blood Glucose; Carbamates; Catalase; Diabetes Mellitus, Experimental; Glutathione; Glutathione Peroxidase; Hyperglycemia; Hypoglycemic Agents; Lipid Peroxidation; Lung; Male; Oxidative Stress; Pioglitazone; Piperidines; Rabbits; Reactive Nitrogen Species; Superoxide Dismutase; Thiazolidinediones; Tyrosine

To investigate the different effects between sulfonylurea (SU) and glinide drugs in insulin secretion, pancreatic beta-cells were repeatedly stimulated with SU (glimepiride) or glinide (mitiglinide). Total internal reflection fluorescent (TIRF) microscopy revealed that secondary stimulation with glimepiride, but not glucose and mitiglinide, failed to evoke fusions of insulin granules although primary stimulation with glucose, glimepiride, and mitiglinide induced equivalent numbers of exocytotic responses. Glimepiride, but not glucose and mitiglinide, induced abnormally sustained [Ca(2+)](i) elevations and reductions of docked insulin granules on the plasma membrane. Our data suggest that the effect of glinide on insulin secretory mechanisms is similar to that of glucose.

Topics: Animals; Calcium; Carbamates; Cell Fusion; Cells, Cultured; Cyclohexanes; Exocytosis; Glucose; Hypoglycemic Agents; Insulin; Insulin Secretion; Insulin-Secreting Cells; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Nateglinide; Phenylalanine; Piperidines; Sulfonylurea Compounds

Repaglinide (RPG) is an oral hypoglycemic agent with excellent bioavailability (90-98%) and a short plasma half-life (2-6 h). A full dose of RPG is required before each meal; hence, therapy may become inconvenient. Thus, the aim of the present study was to design a novel delivery system to maintain peak plasma levels of RPG for the long-term management of diabetes mellitus.. Two nanoparticle formulations were prepared by combining RPG with poly (lactic-co-glycolic) acid alone or as a copolymer with methoxypolyethylene glycol (RPGNP1 and RPGNP2, respectively); both formulations were subjected to in vitro and in vivo characterization. In vivo characterization was performed in a streptozotocin (STZ)-induced diabetic male albino rats.. The mean particle size of the RPGNP1 and RPGNP2 formulations was 387.8 ± 11.9 and 310.2 ± 12.4 nm, respectively, with a zeta potential of -27.4 ± 0.7 and -15.7 ± 0.5 mV, respectively. The entrapment efficiency and drug content of RPGNP1 (58.7 ± 1.3% and 27.4 ± 2.3%, respectively) was better than that of RPGNP2 (45.8 ± 1.2% and 24.3 ± 1.1%, respectively). Blood glucose levels of RPGNP1- and RPGNP2-treated STZ-diabetic rats were reduced significantly (to normal levels) compared with untreated STZ-diabetic rats (P < 0.05), but there was no difference between the two treatment groups (P > 0.05). However, whereas RPGNP1 was effective for a period of only 24 h, RPGNP2 was effective for up to 1 week.. The results of the present study show that RPGNP2 effectively manages type 2 diabetes mellitus for up to 1 week. Surface-modified NPs could be used to improve patient compliance with drug treatment as a result of decreased dosing frequency.

Topics: Administration, Oral; Animals; Blood Glucose; Carbamates; Chemistry, Pharmaceutical; Delayed-Action Preparations; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Disease Models, Animal; Drug Compounding; Hypoglycemic Agents; Lactic Acid; Male; Nanoparticles; Particle Size; Piperidines; Polyethylene Glycols; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Rats; Rats, Sprague-Dawley; Solubility

The aim of this study was to investigate the association of KCNJ11 E23K and ABCC8 exon16-3T/C with the therapeutic effect of repaglinide in patients with type 2 diabetes.. A total of 100 Chinese patients with newly diagnosed type 2 diabetes were treated with repaglinide for 24 weeks. Arginine stimulation tests were performed to evaluate beta cell function. Gene variations were detected with PCR-restriction fragment length polymorphism. Responders were defined by a greater than 25% decrease in fasting plasma glucose or a greater than 20% decrease in hemoglobin A1c (HbA1c) values (or both) after the 24 week repaglinide treatment.. Both baseline HbA1c and the decrease of HbA1c were significantly higher in patients with E/K and K/K genotypes of the KCNJ11 E23K variant when compared with E/E homozygotes (P=0.0103 and 0.0221, respectively). The decrease in 2 h postprandial plasma glucose (2hPG) was significantly greater in E/K heterozygotes than E/E homozygotes (P=0.0367). There was a significant difference in the response rate to repaglinide treatment between the E and K alleles (68% vs 82%, P=0.0324). The changes in fasting insulin and the homeostasis model assessment of insulin resistance were significantly greater in patients with ABCC8 exon16-3 C/C versus the T/C and T/T genotypes (P=0.0372 and 0.0274, respectively).. The KCNJ11 E23K variant was associated with the therapeutic effect of repaglinide. In addition, The C/C homozygotes of the ABCC8 exon16-3T/C variant responded better to repaglinide in insulin sensitivity than the T/C and T/T genotypes.

Topics: ATP-Binding Cassette Transporters; Carbamates; Diabetes Mellitus, Type 2; DNA; Female; Gene Frequency; Genotype; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Polymorphism, Genetic; Potassium Channels, Inwardly Rectifying; Receptors, Drug; Sulfonylurea Receptors

To establish whether the effect of SLCO1B1[encoding organic anion transporting polypeptide 1B1 (OATP1B1)] c.521T-->C (p.Val174Ala) polymorphism on the pharmacokinetics of repaglinide is dose-dependent.. Twelve healthy volunteers with the SLCO1B1 c.521TT genotype (controls) and eight with the c.521CC genotype ingested a single 0.25-, 0.5-, 1- or 2-mg dose of repaglinide in a dose-escalation study with a wash-out period of > or =1 week.. The mean area under the plasma concentration-time curve from time 0 to infinity (AUC(0-infinity)) of 0.25, 0.5, 1 or 2 mg repaglinide was 82% (95% confidence interval 47, 125), 72% (24, 138), 56% (24, 95) or 108% (59, 171) (P < or = 0.001) larger in participants with the SLCO1B1 c.521CC genotype than in those with the c.521TT genotype, respectively. Repaglinide peak plasma concentration and AUC(0-infinity) increased linearly along with repaglinide dose in both genotype groups (r > 0.88, P < 0.001). There was a tendency towards lower blood glucose concentrations after repaglinide administration in the participants with the c.521CC genotype than in those with the c.521TT genotype.. The effect of SLCO1B1 c.521T-->C polymorphism on the pharmacokinetics of repaglinide persists throughout the clinically relevant dose range.

Topics: Area Under Curve; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Female; Genotype; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Male; Metabolic Clearance Rate; Organic Anion Transporters; Piperidines; Polymorphism, Single Nucleotide; Young Adult

Mechanism of interaction of antidiabetic drugs, repaglinide and gliclazide, to human serum albumin has been studied using fluorescence spectroscopic technique. Repaglinide had much higher affinity for human serum albumin when compared with gliclazide. The order of association constants was 10(5) for both the drugs. The size, hydrophobicity and flexibility of the drug molecules play a major role in explaining the binding behaviour of these drugs. Hydrophobic interactions are predominantly involved in the binding. However, drugs do not share common sites with 1-anilinonaphthalene-8-sulphonate on the human serum albumin molecule. Both tyrosine and tryptophan residues participate in the interaction. Repaglinide and gliclazide are bound to site II on the human serum albumin molecule, and the aromatic ring of 411Tyr appears to be involved in binding within site II. Although they do not bind at site I, their binding at site II may cause conformational changes thereby affecting the binding of other ligands to site I. Site-specificity can be useful in predicting the competitive displacement of these drugs by other co-administered drugs, resulting in fluctuations of the blood glucose levels in diabetic patients. Stern-Volmer analysis of quenching data indicated that the tryptophan residues are not fully accessible to the drugs and predominantly dynamic quenching mechanism is involved in the binding.

Topics: Anilino Naphthalenesulfonates; Binding Sites; Carbamates; Fluorescent Dyes; Gliclazide; Humans; Hydrophobic and Hydrophilic Interactions; Hypoglycemic Agents; Models, Biological; Piperidines; Protein Binding; Serum Albumin; Spectrometry, Fluorescence; Thermodynamics; Tryptophan

Cytochrome P450 2C8 (CYP2C8) plays a major role in the metabolism of therapeutically important drugs which exhibit large interindividual differences in their pharmacokinetics. In order to evaluate any genetic influence on this variation, a CYP2C8 phenotype-genotype evaluation was carried out in Caucasians. Two novel CYP2C8 haplotypes, named B and C with frequencies of 24 and 22% in Caucasians, respectively, were identified and caused a significantly increased and reduced paclitaxel 6alpha-hydroxylation, respectively, as evident from analyses of 49 human liver samples. In healthy white subjects, CYP2C8*3 and the two novel haplotypes significantly influenced repaglinide pharmacokinetics in SLCO1B1c.521T/C heterozygous individuals: haplotype B was associated with reduced and haplotype C with increased repaglinide AUC (0-infinity). Functional studies suggested -271C>A (CYP2C8*1B) as a causative SNP in haplotype B. In conclusion, two novel common CYP2C8 haplotypes were identified and significantly associated with altered rate of CYP2C8-dependent drug metabolism in vitro and in vivo.

Topics: Aryl Hydrocarbon Hydroxylases; Carbamates; Cytochrome P-450 CYP2C8; Genetic Variation; Haplotypes; Humans; Paclitaxel; Piperidines; White People

The electrochemical oxidation of repaglinide has been carried out in Britton-Robinson buffer at carbon paste and glassy carbon electrodes. Repaglinide exhibits a well-defined irreversible oxidation peak over the entire pH range (2-11). Differential pulse voltammetry was used to determine repaglinide in pure form. The peak current varied linearly in the following ranges: 8.0 x 10(-7)-3.2 x 10(-6) M and 4.0 x 10(-7)-4.0 x 10(-6) M in case of carbon paste electrode and glassy carbon electrode, respectively. In case of carbon paste electrode the limits of detection (LOD) and quantification (LOQ) were 1.348 x 10(-7) M and 4.494 x 10(-7) M, respectively. For glassy carbon electrode the LOD and LOQ were 1.062 x 10(-7) M and 3.54 x 10(-7) M, respectively. The percentage recoveries were found in the following ranges: 99.09-100.07% and 99.0-100.50% for carbon paste electrode and glassy carbon electrode, respectively. The relative standard deviations were found in the following ranges: 0.636-1.395% and 0.431-1.104% in case of carbon paste electrode and glassy carbon electrode, respectively. Differential pulse voltammetry was successfully applied for the determination of repaglinide in tablets and human serum.

Topics: Carbamates; Carbon; Electrochemistry; Electrodes; Humans; Hydrogen-Ion Concentration; Hypoglycemic Agents; Oxidation-Reduction; Piperidines; Tablets

Intrasperm calcium concentration ([Ca2+]is) is known to play a vital role in regulating motility and viability of ejaculated spermatozoa. K ATP channel blockers are reported to block K ATP channels, leading to depolarization of the cell membrane. This activates the voltage-gated calcium channels, resulting in enhanced Ca2+ influx, which eventually elevates the intracellular [Ca2+] level. Hence, it can be hypothesized that drugs acting on K ATP channels could possess the ability to elevate [Ca2+]is. Sulfonylureas such as glibenclamide or gliclazide, as well as meglitinide analogues such as repaglinide, produced a dose- and time-dependent decrease in viability, each requiring 7.5 mM, 10 mM and 6.5 mM, respectively, to produce death of all sperm cells immediately upon addition to ejaculated human semen samples. The reduction in sperm viability was accompanied by an elevation of [Ca2+]is and was affected by removal of extracellular Ca2+. Significantly (P < 0.05) less time was required to elevate [Ca2+](is) and produce complete loss of sperm viability when any of these drugs were added to sperm cells simultaneously with selected agents affecting Ca2+ homeostasis. Thus, the spermicidal activity of these drugs attributed to elevation of [Ca2+]is and their synergism can be potentially exploited for developing contact spermicidal formulations.

Topics: Adult; Benzamides; Calcium; Carbamates; Cross-Over Studies; Dose-Response Relationship, Drug; Gliclazide; Glyburide; Homeostasis; Humans; Hypoglycemic Agents; KATP Channels; Male; Piperidines; Sperm Motility; Spermatocidal Agents; Spermatozoa; Sulfonylurea Compounds; Time Factors

Topics: Carbamates; Cyclohexanes; Glipizide; Humans; Hyperglycemia; Hyperlipidemias; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines; Postprandial Period; Sulfonylurea Compounds

The uptake of drugs into hepatocytes is a key determinant for hepatic metabolism, intrahepatic action, their subsequent systemic plasma concentrations, and extrahepatic actions. In vitro and in vivo studies indicate that many drugs used for treatment of cardiovascular diseases (e.g., oral antidiabetic drugs, statins) are taken up into hepatocytes by distinct organic anion transporters (organic anion transporting polypeptides [OATPs]; gene symbol SLCO/SLC21) or organic cation transporters (OCTs; gene symbol SLC22). Because most patients with type 2 diabetes receive more than one drug and inhibition of drug transporters has been recognized as a new mechanism underlying drug-drug interactions, we tested the hypothesis of whether oral antidiabetic drugs can inhibit the transport mediated by hepatic uptake transporters.. Using stably transfected cell systems recombinantly expressing the uptake transporters OATP1B1, OATP1B3, OATP2B1, or OCT1, we analyzed whether the antidiabetic drugs repaglinide, rosiglitazone, or metformin influence the transport of substrates and drugs (for OATPs, sulfobromophthalein [BSP] and pravastatin; for OCT1, 1-methyl-4-phenylpyridinium [MPP(+)] and metformin).. Metformin did not inhibit the uptake of OATP and OCT1 substrates. However, OATP-mediated BSP and pravastatin uptake and OCT1-mediated MPP(+) and metformin uptake were significantly inhibited by repaglinide (half-maximal inhibitory concentration [IC(50)] 1.6-5.6 micromol/l) and rosiglitazone (IC(50) 5.2-30.4 micromol/l).. These in vitro results demonstrate that alterations of uptake transporter function by oral antidiabetic drugs have to be considered as potential mechanisms underlying drug-drug interactions.

Topics: Administration, Oral; Animals; Biological Transport; Carbamates; Cell Line; Dogs; Hepatocytes; Humans; Hypoglycemic Agents; Kidney; Kinetics; Liver; Liver-Specific Organic Anion Transporter 1; Metformin; Organic Anion Transporters; Organic Anion Transporters, Sodium-Independent; Piperidines; Pravastatin; Recombinant Proteins; Rosiglitazone; Solute Carrier Organic Anion Transporter Family Member 1B3; Thiazolidinediones

A prescription is a health-care program implemented by a physician or other qualified practitioner in the form of instructions that govern the plan of care for an individual patient. Although the algorithmic nature of prescriptions is axiomatic, this insight has not been applied systematically to medication safety. We used software design principles and debugging methods to create a "Patient-oriented Prescription for Analgesia" (POPA), assessed the rate and extent of adoption of POPA by physicians, and conducted a statistical process control clinical trial and a subsidiary cohort analysis to evaluate whether POPA would reduce the rate of severe and fatal opioid-associated adverse drug events (ADEs). We conducted the study in a population of 153,260 hospitalized adults, 50,576 (33%) of whom received parenteral opioids. Hospitalwide, the use of POPA increased to 62% of opioid prescriptions (diffusion half-life = 98 days), while opioid-associated severe/fatal ADEs fell from an initial peak of seven per month to zero per month during the final 6 months (P < 0.0016) of the study. In the nested orthopedics subcohort, the use of POPA increased the practice of recording pain scores (94% vs. 72%, P < 0.00001) and the use of adjuvant analgesics (95% vs. 40%, P < 0.00001) and resulted in fewer opioid-associated severe ADEs than routine patient-controlled analgesia (PCA) (0% vs. 2.7%, number needed to treat (NNT) = 35, P < 0.015). The widespread diffusion of POPA was associated with a substantial hospitalwide decline in opioid-associated severe/fatal ADEs.

Topics: Adult; Aged; Analgesia, Patient-Controlled; Analgesics, Opioid; Blood Glucose; Carbamates; Clinical Trials as Topic; Drug Interactions; Female; Gemfibrozil; Hospital Mortality; Humans; Hypoglycemic Agents; Hypolipidemic Agents; Male; Medication Errors; Middle Aged; Multicenter Studies as Topic; Pain; Patient-Centered Care; Piperidines; Software

For patients with type 2 diabetes, the American Diabetes Association (ADA) and European Association for the Study of Diabetes (EASD) currently recommend a glycosylated hemoglobin (HbA(1c) ) target of <7%, and the British Medical Association (BMA) Quality and Outcomes Framework recommends an HbA(1c) target of >or=7.5%.. This letter presents a reanalysis of data from a previous study of the effect on glycemic control of adding repaglinide to metformin monotherapy in patients with type 2 diabetes to determine the proportion of patients achieving current ADA/EASD and BMA targets.. PubMed was searched using the terms repaglinide AND metformin AND HbA(1c) to identify published comparisons of monotherapy and combination therapy with these drugs in patients with type 2 diabetes.. In the original analysis, which employed an HbA(1c) target of <7.1%, 59%of patients treated with metformin plus repaglinide achieved their glycemic target, compared with approximately 20% of patients treated with metformin or repaglinide alone. On reanalysis of the data according to the current ADA/EASD HbA(1c) target of <7%, 56% of patients receiving metformin and repaglinide achieved that goal,compared with 19%each in the groups treated with metformin or repaglinide monotherapy. On reanalysis of the data according to the BMA Quality and Outcomes Framework HbA(1c) target of >or=7.5%, 89% of patients receiving metformin and repaglinide achieved that goal, compared with 43%and 42% of patients receiving metformin and repaglinide monotherapy, respectively.. Based on this reanalysis of earlier data in terms of currently recommended HbA(1c) targets, combination therapy with repaglinide and metformin would appear to be a good treatment option for patients with type 2 diabetes.

Topics: Biomarkers; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Metformin; Piperidines; Randomized Controlled Trials as Topic; Treatment Outcome

Many drugs have been reported to interact with repaglinide in patients with type 2 diabetes mellitus, resulting in hypoglycemia. However, to our knowledge, an interaction between clarithromycin and repaglinide in these patients has not been previously reported. We describe an 80-year-old man with end-stage renal disease and well-controlled type 2 diabetes (hemoglobin A1c < 7%) who was hospitalized for treatment of severe hypoglycemia. He had been receiving repaglinide 0.5 mg 3 times/day for the previous 2 years. Clarithromycin 500 mg twice/day had been started for Helicobacter pylori infection several days before admission. Within 48 hours of starting the drug, he developed severe hypoglycemia, which resolved with intravenous glucose administration. However, 48 hours later, the patient again experienced hypoglycemia and was unresponsive. Intravenous glucose administration again resolved the problem. Repaglinide was discontinued, and no further hypoglycemic episodes occurred. Clinicians should be aware of this possible clarithromycin-repaglinide interaction; in particular, in elderly patients with type 2 diabetes who are taking repaglinide and begin clarithromycin therapy, blood glucose levels should be monitored closely for potential dosage adjustment of repaglinide.

Topics: Aged, 80 and over; Anti-Bacterial Agents; Blood Glucose; Carbamates; Clarithromycin; Diabetes Mellitus, Type 2; Drug Interactions; Helicobacter Infections; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Piperidines

Although diabetics may be exempted from Ramadan fasting, many patients still insist on this worship. Aim of the present study is to compare the effects of glimepiride, repaglinide, and insulin glargine in type 2 diabetics during Ramadan fasting on the glucose metabolism. Patients, who were willing to fast, were treated with glimepiride (n=21), repaglinide (n=18), and insulin glargine (n=10). Sixteen non-fasting control type 2 diabetics matched for age, sex, and body mass index were also included. Fasting blood glucose (FBG), post-prandial blood glucose (PBG), HbA1c, and fructosamine as well as lipid metabolism were evaluated in pre-Ramadan, post-Ramadan, and 1-month post-Ramadan time points. There was no significant change from pre-Ramadan in FBG, PBG, and HbA1c variables in fasting diabetics at post-Ramadan and 1-month post-Ramadan. However, PBG was found higher in non-fasting control diabetics at post-Ramadan and 1-month post-Ramadan (p<0.05 and p<0.001, respectively). In fructosamine levels, a significant increase was noted both in fasting group and non-fasting group at 1-month post-Ramadan (p<0.01 for all). However, no significant difference was found in the comparison of the changes in fructosamine levels between fasting group and non-fasting group. Risk of hypoglycemia did not significantly differ between fasting and non-fasting diabetics. There was no significant difference between three drug therapies regarding glucose metabolism and rate of hypoglycemia. No adverse effects on plasma lipids were noted in fasting diabetics. In this fasting sample of patients with type 2 diabetes, glimepiride, repaglinide, and insulin glargine did not produce significant changes in glucose and lipid parameters.

Topics: Adult; Body Mass Index; Carbamates; Diabetes Mellitus, Type 2; Fasting; Female; Fructosamine; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Glargine; Insulin, Long-Acting; Islam; Male; Middle Aged; Patient Selection; Piperidines; Sulfonylurea Compounds; Turkey

The role of K(ATP) channels in the antiarrhythmic effect of Escherichia coli endotoxin-induced nitric oxide synthase (iNOS) was examined in an anesthetised rat model of myocardial ischemia and reperfusion arrhythmia by using glibenclamide (1 mg kg(-1)), nateglinide (10 mg kg(-1)) and repaglinide (0.5 mg kg(-1)). Endotoxin (1 mg kg(-1)) was administered intraperitoneally 4 h before the occlusion of the left coronary artery and glibenclamide, nateglinide or repaglinide was administered 30 min before coronary artery occlusion. We also evaluated the effects of K(ATP) channel blockers and nonselective K(+) channel blocker tetraethylammonium (TEA) on cardiac action potential configuration in the atria obtained from endotoxemic rats. The mean arterial blood pressure of rats receiving endotoxin was lower during both the occlusion and reperfusion periods. Endotoxin significantly reduced the total number of ectopic beats and the duration of ventricular tachycardia. Glibenclamide, but not nateglinide and repaglinide, prevented the hypotension and antiarrhythmic effects of endotoxin. Atria obtained from endotoxin-treated rats had prolonged action potential duration. This effect was abolished with pretreatment of iNOS inhibitors, l-canavanine and dexamethasone and perfusion of glibenclamide, but not with TEA and non-sulfonylurea drug, nateglinide. We demonstrated that glibenclamide inhibits the antiarrhythmic effect of endotoxin and this effect does not appear to involve K(ATP) channels.

Topics: Action Potentials; Adenosine Triphosphate; Animals; Arrhythmias, Cardiac; Blood Pressure; Carbamates; Cyclohexanes; Disease Models, Animal; Drug Interactions; Endotoxemia; Glyburide; Heart Atria; Heart Conduction System; Lipopolysaccharides; Male; Myocardial Ischemia; Nateglinide; Phenylalanine; Piperidines; Potassium Channel Blockers; Potassium Channels; Rats; Rats, Sprague-Dawley; Tachycardia, Ventricular; Tetraethylammonium; Time Factors; Ventricular Fibrillation; Ventricular Premature Complexes

In the past few years, oral antihyperglycaemic agents have been considered as an alternative to insulin therapy in the treatment of gestational diabetes. There is still little information available on the safety of these drugs during pregnancy, but there have been several studies published regarding their use. Here we report on the case of a woman who took repaglinide up to the seventh week of pregnancy. Delivery occured with no complications and the newborn showed no malformations. Further studies are required to confirm the safety of repaglinide during pregnancy.

Topics: Adult; Carbamates; Diabetes Mellitus, Type 2; Embryonic Development; Female; Humans; Hypoglycemic Agents; Infant, Newborn; Maternal-Fetal Exchange; Piperidines; Pregnancy; Pregnancy in Diabetics

In this study, the development and validation of a high-performance liquid chromatography (HPLC) assay for determination of repaglinide concentration in human plasma for pharmacokinetic studies is described. Plasma samples containing repaglinide and an internal standard, indomethacin were extracted with ethylacetate at pH 7.4. The recovery of repaglinide was 92%+/-55.31. Chromatographic separations were performed on Purospher STAR C-18 analytical column (4.8 mm x 150 mm; 5 microm particle size). The mobile phase composed of acetonitrile-ammonium formate (pH 2.7; 0.01 M) (60:40, v/v). The flow rate was 1 ml/min. The retention time for repaglinide and indomethacin were approximately 6.2 and 5.3 min, respectively. Calibration curves of repaglinide were linear in the concentration range of 20-200 ng/ml in plasma. The limits of detection and quantification were 10 ng/ml and 20 ng/ml, respectively. The inter-day precision was from 5.21 to 11.84% and the intra-day precision ranged from 3.90 to 6.67%. The inter-day accuracy ranged 89.95 to 105.75% and intra-day accuracy ranged from 92.37 to 104.66%. This method was applied to determine repaglinide concentration in human plasma samples for a pharmacokinetic study.

Topics: Carbamates; Chromatography, High Pressure Liquid; Drug Stability; Freezing; Humans; Hypoglycemic Agents; Molecular Structure; Piperidines; Reference Standards; Reproducibility of Results; Sensitivity and Specificity

Pharmaceutical counterfeiting is becoming a serious problem in the world, especially in developing countries including China. Herein an isocratic reversed-phase high performance liquid chromatography (RP-HPLC) method was developed for screening counterfeit medicines and adulterated dietary supplement products. The developed method could be employed to separate and determine simultaneously six anti-diabetic drugs (glipizide, gliclazide, glibenclamide, glimepiride, gliquidone, repaglinide) on an isocratic solvent system using an Alltima C18 column (5 microm, 150 mmx4.6 mm) with an isocratic mobile phase of methanol-phosphate buffer (pH 3.0; 0.01 mol/L) (70:30, v/v), at a flow rate of 1.0 mL/min and at a wavelength of 230 nm. The proposed method was successfully applied to the analysis of medicinal and dietary supplement samples purchased from the local market in China.

Topics: Carbamates; Chromatography, High Pressure Liquid; Gliclazide; Glipizide; Glyburide; Hypoglycemic Agents; Molecular Structure; Piperidines; Reproducibility of Results; Sulfonylurea Compounds

ATP-sensitive K(+) (K(ATP)) channels are composed of pore-forming subunits (Kir6.x) and of regulatory subunits, the sulfonylurea receptors (SURx). Subtypes of K(ATP) channels are expressed in different organs. The sulfonylureas and glinides (insulinotropes) close the K(ATP) channel in pancreatic beta-cells and stimulate insulin secretion. The insulinotrope binding site of the pancreatic channel (Kir6.2/SUR1) consists of two overlapping (sub)-sites, site A, located on SUR1 and containing Ser1237 (which in SUR2 is replaced by Tyr1206), and site B, formed by SUR1 and Kir6.2. Insulinotropes bind to the A-, B-, or A + B-site(s) and are grouped accordingly. A-ligands are highly selective in closing the pancreatic channel, whereas B-ligands are nonselective and insensitive to the mutation S1237Y. We have examined the binding of insulinotropes representative of the three groups in [(3)H]glibenclamide competition experiments to determine the contribution of Kir6.x to binding affinity, the effect of the mutation Y1206S in site A of SUR2, and the subtype selectivity of the compounds. The results show that the bipartite nature of the SUR1 binding site applies also to SUR2. Kir6.2 as part of the B-site may interact directly or allosterically with structural elements common to all insulinotropes, i.e., the negative charge and/or the adjacent phenyl ring. The B-site confers a moderate subtype selectivity on B-ligands. The affinity of B-ligands is altered by the mutation SUR2(Y1206S), suggesting that the mutation affects the binding chamber of SUR2 as a whole or subsite A, including the region where the subsites overlap.

Topics: Amino Acid Substitution; Animals; ATP-Binding Cassette Transporters; Binding Sites; Binding, Competitive; Carbamates; Cell Line; Cyclohexanes; Dose-Response Relationship, Drug; Glyburide; Hypoglycemic Agents; KATP Channels; Ligands; Mice; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Protein Binding; Radioligand Assay; Rats; Receptors, Drug; Sulfonylurea Compounds; Sulfonylurea Receptors; Transfection

A floating granular delivery system consisting of calcium silicate (CS) as porous carrier; repaglinide (Rg), an oral hypoglycemic agent; and hydroxypropyl methylcellulose K4M (HPMC K4M), ethyl cellulose (EC) and carbopol 940 (CP940) as matrix forming polymers was prepared and evaluated for its gastro-retentive and controlled release properties. The effect of various formulation and process variables on the particle morphology, micromeritic properties, in vitro floating behavior, drug content (%) and in vitro drug release was studied. The transit of floating granules of optimized formulation in the gastrointestinal (GI) tract was monitored by gamma scintigraphy in albino rabbits. The optimized formulation was compared in vivo with lactose granules (RgSCLG) prepared from identical polymers with their optimized composition ratio. Repaglinide-loaded optimized formulation was orally administered to albino rabbits and blood samples collected were used to determine pharmacokinetic parameters of Rg from floating granular formulation. Results were compared with pharmacokinetic parameters of marketed tablet formulation of Rg. The optimized formulation (RgSCG4) demonstrated favorable in vitro floating and release characteristics. Prolonged gastric residence time (GRT) of over 6 hr was achieved in all subjects for calcium silicate based floating granules of Rg. The relative bioavailability of Rg-loaded floating granules increased 3.8-fold in comparison to that of its marketed capsule. The designed system, combining excellent buoyant ability and suitable drug release pattern, offered clear advantages in terms of increased bioavailability of repaglinide.

Topics: Acrylic Resins; Administration, Oral; Animals; Biological Availability; Calcium Compounds; Carbamates; Cellulose; Chemistry, Pharmaceutical; Delayed-Action Preparations; Drug Carriers; Gastrointestinal Transit; Hypoglycemic Agents; Hypromellose Derivatives; Male; Methylcellulose; Particle Size; Piperidines; Polymers; Porosity; Rabbits; Radionuclide Imaging; Silicates

The objective of the study was to produce rapidly dissolving formulations of the poorly water-soluble drug repaglinide using an innovative new technology, ultra-rapid freezing (URF), and to investigate the influence of excipient type on repaglinide stability. Repaglinide compositions containing different types and levels of excipients and different drug potencies (50%-86%) were produced by the URF technology. Repaglinide/excipient solutions were frozen on a cryogenic substrate, collected, and lyophilized to form a dry powder. Surfactants, including sodium dodecyl sulfate, and alkalizing agents such as diethanolamine (DEA) and tromethamine (TRIS) were incorporated into the compositions. Forced degradation of repaglinide was conducted under stressed conditions (eg, elevated temperature, exposure to peroxide) to determine the stability of the drug in such environments. The solubility of repaglinide increased as a function of increasing pH; therefore, incorporation of an alkalizing agent into the URF formulations increased the drug's solubility. Drug instability resulted when the drug was exposed to pH values above 9.0. URF formulations containing alkalizing agents showed no degradation or spontaneous recrystallization in the formulation, indicating that increased stability was afforded by processing. URF processing created nanostructured drug/excipient particles with higher dissolution rates than were achieved for unprocessed drug. Alkalizing agents such as TRIS and DEA, present at levels of 25% to 33% wt/wt in the formulations, did not cause degradation of the drug when processed using URF. URF processing, therefore, yielded fast-dissolving formulations that were physically and chemically stable, resistant to alkali degradation or spontaneous recrystallization in the formulation.

Topics: Carbamates; Chemistry, Pharmaceutical; Freezing; Hydrogen-Ion Concentration; Piperidines; Powders; Solubility; Technology, Pharmaceutical; X-Ray Diffraction

This paper describes a convenient method for the separation and simultaneous determination of six anti-diabetic drugs viz., glibenclamide (GLB), gliclazide (GLC), glipizide (GLZ), pioglitazone (PGL), repaglinide (RPG) and rosiglitazone (RGL) in pharmaceutical formulations. Also, the assay has been shown applied to support quantification of the six anti-diabetic drugs in human plasma. The analytes were either injected directly onto the column after suitable dilution (pharmaceutical formulation analysis) or a simple extraction procedure, using acetonitrile, from human plasma spiked with anti-diabetic drugs and internal standard (IS). Ternary gradient elution at a flow rate of 1 mL/min was employed on an Intertisl ODS 3V column (4.6 x 250 mm, 5 microm) at ambient temperature. The mobile phase consisted of 0.01 m formic acid (pH 3.0), acetonitrile, Milli Q water and methanol. Celecoxib was used as an IS. The six anti-diabetic drugs were monitored at a wavelength of 260 nm. The nominal retention times of RGL, PGL, GLZ, GLC, GLB, IS and RGL were 11.4, 13.3, 14.8, 17.6, 20.78, 22.1 and 25.4 min, respectively. The assay developed for formulation analysis was found to be accurate and precise. The calibration curves ranged from 0.1 to 100 microg/mL for all analytes with the exception of GLB, where the range was 0.3-100 microg/mL. The plasma assay was validated for parameters such as specificity, accuracy and extraction recovery. The proposed method is simple, selective and can be extended for routine analysis of anti-diabetics in pharmaceutical preparations and in biological matrices.

Topics: Carbamates; Chromatography, High Pressure Liquid; Gliclazide; Glipizide; Glyburide; Humans; Hypoglycemic Agents; Molecular Structure; Pioglitazone; Piperidines; Reproducibility of Results; Rosiglitazone; Thiazolidinediones

Potentiometric and spectrophotometric titrations were used for the determination of ionization behaviour, lipophilicity and solubility profile of repaglinide. Acid-base equilibria were characterized by means of protonation macro- and microconstants using Target Factor Analysis of spectrophotometric data. Lipophilicity profiles were evaluated by determination of partition coefficients of neutral and ionized forms of repaglinide in biphasic octanol/water system. The intrinsic solubilities of repaglinide were determined from the solubility data and temperature dependence of intrinsic solubilities were evaluated using van't Hoff equation. Repaglinide possesses two protonation sites and in aqueous solutions exhibits ampholitic properties. At isoelectric pH the zwitterionic form of the molecule predominates over the uncharged form with the tautomeric ratio, logKz=1.9. The difference between calculated and measured logP values, as well as the difference between logP values of uncharged form of repaglinide, HR0, and either one of mono-charged forms indicated the significant partition of zwitterion into octanol. Temperature dependence of solubility data revealed exothermic dissolution process with DeltasolH=-36 kJmol-1 and negative entropy of solution of DeltasolS=-0.19 kJK-1mol-1.

Topics: Carbamates; Hydrogen-Ion Concentration; Hypoglycemic Agents; Isoelectric Point; Lipids; Piperidines; Solubility; Spectrophotometry, Ultraviolet

Repaglinide is a prandial glucose regulator indicated for management of type 2 diabetes. This post-marketing study used the observational cohort technique of prescription-event monitoring (PEM) to monitor safety of repaglinide prescribed in primary care in England. Patients were identified from dispensed prescriptions issued by general practitioners (GPs) between December 1998 and January 2001. Demographic and clinical event data were collected from questionnaires posted to GPs at least six months after the date of first prescription for each patient. The cohort consisted of 5731 patients [median age 60 (IQR 51-68), 49.9% male]. Event incidence densities (IDs) [no. 1st reports/1000 patient-months of exposure] were calculated for all events reported. The most frequently recorded clinical events in the first month were diarrhoea (ID(1) 10.3), malaise/lassitude (ID(1) 8.1) and nausea/vomiting (ID(1) 7.9). The most frequently reported reason for stopping was 'not effective' (647), with the most common clinical reasons being diarrhoea (60), malaise/lassitude (55) and intolerance (54). One hundred and thirteen adverse drug reactions (ADRs) were reported, with the most frequently specified being diarrhoea (10), abdominal pain (10) and nausea/vomiting (9). We concluded that repaglinide is generally well tolerated when used in general practice in England and did not identify any serious unrecognised adverse events.

Topics: Aged; Carbamates; Cause of Death; Cohort Studies; Diabetes Mellitus, Type 2; Drug Prescriptions; England; Family Practice; Female; Humans; Hypoglycemic Agents; Infant; Middle Aged; Piperidines; Pregnancy; Safety; State Medicine; Survival Analysis; Vision Disorders

The objective of the present investigation was to evaluate gastro-retentive performance and pharmacokinetic parameters of optimized floating microspheres (RgFMCS4) consisting of (i) calcium silicate (CS) as porous carrier; (ii) repaglinide (Rg), an oral hypoglycemic agent; and (iii) Eudragit S (ES) as polymer. The optimized formulation demonstrated favorable in-vitro-floating and drug release characteristics. The gastro-retentive behavior of this optimized formulation was compared with non-floating microspheres (RgNFM) prepared from the identical polymer. Stability test of (99m)Tc-labeled formulations were carried out using appropriate standard buffer solutions of pH 2.0, 6.8 and 7.4. The organ distribution study was performed in albino rats in order to measure labeling efficiency of the formulation with (99m)Tc. The gamma scintigraphy of the formulations was carried out in albino rabbits to monitor the transit of RgFMCS4 and RgNFM in the gastrointestinal (GI) tract. Prolonged gastric residence time (GRT) of over 6 h was achieved in all animals for calcium silicate based floating microspheres of Rg. Rg loaded optimized formulation was orally administered to albino rabbits and blood samples were used to determine pharmacokinetic parameters of Rg from floating microspheres, which were compared with pharmacokinetic parameters of the marketed tablet formulation. The relative bioavailability of Rg loaded floating microspheres was found to be increased about 3.17 times in comparison to that of the marketed tablet. The enhanced bioavailability and eliminated half-lives of Rg formulation observed in the present study are attributed to the floating nature of the designed formulations.

Topics: Animals; Calcium Compounds; Carbamates; Male; Microspheres; Piperidines; Rabbits; Rats; Rats, Sprague-Dawley; Silicates; Tissue Distribution

Sulfonylureas and glinides close beta cell ATP-sensitive K(+) (K(ATP)) channels to increase insulin release; the concomitant closure of cardiovascular K(ATP) channels, however, leads to complications in patients with cardiac ischaemia. The insulinotrope repaglinide is successful in therapy, but has been reported to inhibit the recombinant K(ATP) channels of beta cells, cardiocytes and non-vascular smooth muscle cells with similar potencies, suggesting that the (patho-)physiological role of the cardiovascular K(ATP) channels may be overstated. We therefore re-examined repaglinide's potency at and affinity for the recombinant pancreatic, myocardial and vascular K(ATP) channels in comparison with glibenclamide.. K(ATP) channel subunits (i.e. inwardly rectifying K(+) channels [Kir6.x] and sulfonylurea receptors [SURx]) were expressed in intact human embryonic kidney cells and assayed in whole-cell patch-clamp and [(3)H]glibenclamide binding experiments at 37 degrees C.. Repaglinide and glibenclamide, respectively, were >or=30 and >or=1,000 times more potent in closing the pancreatic than the cardiovascular channels and they did not lead to complete inhibition of the myocardial channel. Binding assays showed that the selectivity of glibenclamide was essentially based on high affinity for the pancreatic SUR, whereas binding of repaglinide to the SUR subtypes was rather non-selective. After coexpression with Kir6.x to form the assembled channels, however, the affinity of the pancreatic channel for repaglinide was increased 130-fold, an effect much larger than with the cardiovascular channels. This selective effect of coexpression depended on the piperidino substituent in repaglinide.. Repaglinide and glibenclamide show higher potency and efficacy in inhibiting the pancreatic than the cardiovascular K(ATP) channels, thus supporting their clinical use.

Topics: Adenosine Triphosphate; ATP-Binding Cassette Transporters; Binding, Competitive; Carbamates; Cardiovascular System; Cell Line; Dose-Response Relationship, Drug; Glyburide; Humans; Hypoglycemic Agents; Membrane Potentials; Molecular Structure; Pancreas; Patch-Clamp Techniques; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Receptors, Drug; Sulfonylurea Receptors

Topics: Carbamates; Cyclosporine; Cytochrome P-450 Enzyme System; Drug Interactions; Humans; Hypoglycemic Agents; Immunosuppressive Agents; Organic Anion Transporters; Piperidines

Topics: Carbamates; Cyclosporine; Cytochrome P-450 Enzyme System; Drug Interactions; Humans; Hypoglycemic Agents; Immunosuppressive Agents; Organic Anion Transporters; Piperidines

Topics: Adult; Carbamates; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Piperidines; Pregnancy; Pregnancy in Diabetics; Pregnancy Trimester, First

Loss of beta-cell mass and function raises a concern regarding the application of sulfonylureas for the treatment of type 2 diabetes because previous studies have shown that agents that cause closure of inwardly rectifying K(+) sulfonylurea receptor subtype of ATP-sensitive potassium channels, such as tolbutamide and glibenclamide, induce apoptosis in beta-cell lines and rodent islets. Therefore, we investigated the effect of the new insulin secretagogues, repaglinide and nateglinide, and the sulfonylurea, glibenclamide, on beta-cell apoptosis in human islets. Human islets from six organ donors were cultured onto extracellular matrix-coated plates and exposed to glibenclamide, repaglinide, or nateglinide. The doses of the three compounds were chosen according to detected maximal effects, i.e. efficacy. Exposure of human islets for 4 h to 0.1 and 10 microm glibenclamide induced a 2.09- and 2.46-fold increase in beta-cell apoptosis, respectively, whereas repaglinide (0.01 and 1 microm) did not change the number of apoptotic beta-cells. At low concentration (10 microm), nateglinide did not induce beta-cell apoptosis. However, at high concentration of 1000 microm, it induced a 1.49-fold increase in the number of apoptotic beta-cells. Prolonged exposure for 4 d of the islets to the secretagogues induced beta-cell apoptosis. The increase was of 3.71- and 4.4-fold at 0.1 and 10 microm glibenclamide, 2.37- and 3.8-fold at 0.01 and 1 microm repaglinide, and of 3.2- and 4.6-fold at 10 and 1000 microm nateglinide, respectively. Glibenclamide at 0.1-10 nm (doses that were less efficient on insulin secretion) did not induce beta-cell apoptosis after 4 h incubation as well as 0.1 nm after 4 d incubation. However, 1 and 10 nm glibenclamide for 4 d induced a 2.24- and 2.53-fold increase in beta-cell apoptosis, respectively. Taken together, closure of the inwardly rectifying K(+) sulfonylurea receptor subtype of ATP-sensitive potassium channels induces beta-cell apoptosis in human islets and may precipitate the decrease in beta-cell mass observed in patients with type 2 diabetes.

Topics: Adult; Aged; Apoptosis; Calcium; Carbamates; Cells, Cultured; Cyclohexanes; Dose-Response Relationship, Drug; Glyburide; Humans; Hypoglycemic Agents; Insulin; Islets of Langerhans; Middle Aged; Nateglinide; Phenylalanine; Piperidines

1. The beta-cell K(ATP) channel is composed of two types of subunit - the inward rectifier K(+) channel (Kir6.2) which forms the channel pore, and the sulphonylurea receptor (SUR1), which serves as a regulatory subunit. The N-terminus of Kir6.2 is involved in transduction of sulphonylurea binding into channel closure, and deletion of the N-terminus (Kir6.2DeltaN14) results in functional uncoupling of the two subunits. In this study, we investigate the interaction of the hypoglycaemic agents repaglinide and glibenclamide with SUR1 and the effect of Kir6.2 on this interaction. We further explore how the binding properties of repaglinide and glibenclamide are affected by functional uncoupling of SUR1 and Kir6.2 in Kir6.2DeltaN14/SUR1 channels. All binding experiments are performed on membranes in ATP-free buffer at 37 degrees C. 2. Repaglinide was found to bind with low affinity (K(D)=59+/-16 nM) to SUR1 alone, but with high affinity (increased approximately 150-fold) when SUR1 was co-expressed with Kir6.2 (K(D)=0.42+/-0.03 nM). Glibenclamide, tolbutamide and nateglinide all bound with marginally lower affinity to SUR1 than to Kir6.2/SUR1. 3. Repaglinide bound with low affinity (K(D)=51+/-23 nM) to SUR1 co-expressed with Kir6.2DeltaN14. In contrast, the affinity for glibenclamide, tolbutamide and nateglinide was only mildly changed as compared to wild-type channels. 4. In whole-cell patch-clamp experiments inhibition of Kir6.2DeltaN14/SUR1 currents by both repaglinide and nateglinde is abolished. 5. The results suggest that Kir6.2 causes a conformational change in SUR1 required for high-affinity repaglinide binding, or that the high-affinity repaglinide-binding site includes contributions from both SUR1 and Kir6.2. Glibenclamide, tolbutamide and nateglinide binding appear to involve only SUR1.

Topics: Animals; ATP-Binding Cassette Transporters; Binding, Competitive; Carbamates; Cell Line; Cell Membrane; Drug Interactions; Humans; Hypoglycemic Agents; Islets of Langerhans; Mice; Patch-Clamp Techniques; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Receptors, Drug; Sulfonylurea Receptors

Topics: Aged; Carbamates; Chemical and Drug Induced Liver Injury; Cholestasis; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Male; Piperidines

The human proton-coupled small peptide carrier (hPEPT1) is a low-affinity, high-capacity transporter with broad substrate specificity. We have taken an iterative in vitro and in silico approach to the discovery of molecules with hPEPT1 affinity.. A pharmacophore-based approach was taken to identifying hPEPT1 inhibitors. The well-characterized and relatively high affinity ligands Gly-Sar, bestatin, and enalapril were used to generate a common features (HIPHOP) pharmacophore. This consisted of two hydrophobic features, a hydrogen bond donor, acceptor, and a negative ionizable feature.. The pharmacophore was used to search the Comprehensive Medicinal Chemistry (CMC) database of more than 8000 drug-like molecules and retrieved 145 virtual hits mapping to the pharmacophore features. The highest scoring compounds within this set were selected and tested in a stably transfected CHO-hPepT1 cell model. The antidiabetic repaglinide and HMG CoA reductase inhibitor fluvastatin were found to inhibit hPEPT1 with sub-millimolar potency (IC(50) 178 +/- 1.0 and 337 +/- 4 microM, respectively). The pharmacophore was also able to identify known hPEPT1 substrates and inhibitors in further database mining of more than 500 commonly prescribed drugs.. This study demonstrates the potential of combining computational and in vitro approaches to determine the affinity of compounds for hPEPT1 and, in turn, provides insights into key molecular interactions with this transporter.

Topics: Animals; Aspartame; Carbamates; Cell Line; CHO Cells; Computer Simulation; Cricetinae; Cricetulus; Databases, Factual; Dipeptides; Drug Design; Fatty Acids, Monounsaturated; Fluvastatin; Indoles; Ligands; Models, Molecular; Molecular Conformation; Peptide Transporter 1; Piperidines; Protein Binding; Structure-Activity Relationship; Symporters

In this study, the antioxidative properties of repaglinide were examined in tissues of alloxan-induced diabetic rabbits. Glutathione (GSH), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R) and protein carbonyl groups (PCG) were measured after 4 and 8 weeks treatment with repaglinide (0.3 mg/kg daily). In liver, diabetic versus control values (mean +/- S.E.M., p<0.05) for GSH-Px were 181.0 +/- 5.4 mU/mg protein versus 203.1 +/- 1.9 mU/mg protein and 187.4 +/- 6.6 mU/mg protein versus 240.9 +/- 18.8 mU/mg protein. The respective values for GSH were 33.7 +/- 0.4 nmol/mg protein versus 49.0 +/- 1.6 nmol/mg protein and 37.7 +/- 1.0 nmol/mg protein versus 41.2 +/- 0.7 nmol/mg protein. In diabetic kidney, GSSG-R activity (20.6 +/- 1.6 mU/mg protein versus 32.4 +/- 1.5 mU/mg protein and 23.6 +/- 0.6 mU/mg protein versus 36.3 +/- 0.3 mU/mg protein) and GSH level (16.6 +/- 0.5 nmol/mg protein versus 23.2 +/- 0.9 nmol/mg protein and 17.9 +/- 0.5 nmol/mg protein versus 23.2 +/- 0.6 nmol/mg protein) were reduced compared to control. PCG level was elevated in diabetic liver (0.58 +/- 0.02 nmol/mg protein versus 0.16 +/- 0.03 nmol/mg protein at 4 weeks and 0.64 +/- 0.04 nmol/mg protein versus 0.16 +/- 0.03 nmol/mg protein at 8 weeks) and in diabetic kidney (0.32 +/- 0.03 nmol/mg protein versus 0.11 +/- 0.02 nmol/mg protein and 0.35 +/- 0.03 nmol/mg protein versus 0.16 +/- 0.03 nmol/mg protein). Repaglinide did not affect the glucose level but reduced to some extent the oxidative stress enhanced by chronic hyperglycemia. In diabetic kidney, it restored to control values GSSG-R activity (45.4 +/- 2.0 mU/mg protein at 4 weeks and 41.1 +/- 0.07 mU/mg protein at 8 weeks), GSH level (27.0 +/- 0.8 and 26.8 +/- 0.9 nmol/mg protein), and partly PCG level (0.17 +/- 0.02 nmol/mg protein at 8 weeks). The treatment partly affected GSH-Px activity (262.7 +/- 17.6 mU/mg protein) and GSH level (40.4 +/- 1.4 nmol/mg protein) in diabetic liver. This study shows that repaglinide produces measurable antioxidative effects at therapeutic dose.

Topics: Administration, Oral; Animals; Blood Glucose; Body Weight; Carbamates; Diabetes Mellitus, Experimental; Glutathione Peroxidase; Glutathione Reductase; Hypoglycemic Agents; Kidney; Liver; Male; Oxidative Stress; Piperidines; Rabbits; Time Factors

Topics: Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Humans; Hypoglycemic Agents; Male; Middle Aged; Piperidines; Rosiglitazone; Thiazolidinediones

The aim of this study was to analyse the effect of the new oral antidiabetic drug repaglinide on antioxidant factors and lipid peroxidation in tissues of alloxan-induced diabetic rabbits after 4 and 8 weeks treatment. The activity of superoxide dismutase (diabetic vs. control values, mean+/-S.E.M., p<0.05) in diabetic kidney was diminished (1.5+/-0.2 vs. 2.8+/-0.3 and 1.8+/-0.1 vs. 2.9+/-0.3 U/mg protein) and significantly increased after 8 weeks of repaglinide treatment (2.4+/-0.2 U/mg protein). Catalase activity was significantly increased in diabetic liver (67.5+/-3.6 vs. 39.7+/-5.6 and 62.3+/-2.7 vs. 52.6+/-5.3 micromol H(2)O(2)/min/mg protein) and normalised by repaglinide (49.2+/-4.0 and 41.2+/-3.8 micromol H(2)O(2)/min/mg protein). In diabetic kidney the level of ascorbic acid was diminished after 4 weeks (1.5+/-0.1 vs. 3.0+/-0.1 micromol/g tissue) and increased after the drug treatment (2.0+/-0.2 micromol/g tissue). In diabetic kidney the level of lipid peroxidation products was elevated (33.3+/-2.4 vs. 23.7+/-2.4 and 29.5+/-3.1 vs. 18.2+/-0.8 nmol/g tissue) and diminished by repaglinide (10.3+/-1.4 and 13.3+/-3.0 nmol/g tissue). This study shows that oxidative stress in diabetic tissues is partly corrected by repaglinide. The drug does not affect glucose concentration and its antioxidative effect is not secondary to its action on hyperglycaemia. This study suggests an additional advantage of repaglinide which contributes to its effectiveness in therapy.

Topics: Animals; Blood Glucose; Body Weight; Carbamates; Catalase; Diabetes Mellitus, Experimental; Hypoglycemic Agents; Oxidative Stress; Piperidines; Rabbits; Superoxide Dismutase

A large interindividual variability exists in the plasma concentrations of repaglinide. Our aim was to investigate possible associations between the pharmacokinetics of repaglinide and single nucleotide polymorphisms (SNPs) in the genes encoding for the drug transporters organic anion transporting polypeptide 1B1 (OATP1B1) (SLCO1B1 ) and P-glycoprotein ( MDR1 , ABCB1 ) and the drug-metabolizing enzymes cytochrome P450 (CYP) 2C8 and CYP3A5.. A total of 56 healthy volunteers ingested a single 0.25-mg dose of repaglinide. Plasma repaglinide and blood glucose concentrations were measured for up to 7 hours. All subjects were genotyped for the -11187G>A and 521T>C SNPs in SLCO1B1 and the 3435C>T and 2677G>T/A SNPs in ABCB1 , as well as for the CYP2C8*3 (416G>A, 1196A>G), CYP2C8*4 (792C>G), and CYP3A5*3 (6986A>G) alleles.. The area under the plasma concentration-time curve from time 0 to infinity [AUC(0-infinity)] and peak concentration in plasma (Cmax) of repaglinide varied 16.9-fold and 10.7-fold, respectively, between individual subjects. Multiple regression analyses indicated that the SLCO1B1 521T>C SNP and the CYP2C8*3 allele were independent predictors of the AUC(0-infinity) and Cmax of repaglinide (adjusted multiple R2 = 45% and 36%, respectively). In subjects with the SLCO1B1 521CC genotype, the AUC(0-infinity) of repaglinide was 107% and 188% higher, respectively, than in subjects with the SLCO1B1 521TC or 521TT (reference) genotype (P < .0001). In subjects with the CYP2C8*1/*3 genotype, the AUC(0-infinity) and Cmax of repaglinide were 48% and 44% lower, respectively, than in those with the CYP2C8*1/*1 genotype (P < .05). The pharmacokinetics of repaglinide was not associated with the studied ABCB1 SNPs or the CYP3A5*3 allele. The elimination half-life of repaglinide was not associated with any SNP. Only the SLCO1B1 -11187GA genotype was significantly associated with an enhanced effect of repaglinide on blood glucose.. Genetic polymorphism in SLCO1B1 is a major determinant of interindividual variability in the pharmacokinetics of repaglinide. The effect of SLCO1B1 polymorphism on the pharmacokinetics of repaglinide may be clinically important.

Topics: Adult; Aryl Hydrocarbon Hydroxylases; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP-Binding Cassette Transporters; Carbamates; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Female; Genes, MDR; Genotype; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Male; Piperidines; Polymorphism, Single Nucleotide

Oxidative stress, defined as an imbalance between the production of reactive oxygen species (ROS) and antioxidant defense, is considered to be an important pathogenic factor in diabetes mellitus and its complications. In diabetic state, ROS might also be implicated in promoting a state of systemic inflammation. Recently, it was demonstrated that antioxidant therapy could be used to stop the initiation and propagation of this inflammatory response. Repaglinide is a new oral antidiabetic agent with a possible antioxidant activity. Therefore, in the present study, a possible therapeutic value of repaglinide in ameliorating the oxidative and inflammatory processes was tested in diabetic animals. In the study, the levels of total antioxidant status (TAS), ascorbic acid (AA), protein carbonyl groups (PCG) and interleukin-6 (IL-6) were determined in plasma of diabetic rabbits after 4 and 8 weeks of repaglinide treatment (1mg daily). Ex vivo analysis revealed that there were significant differences in these markers between hyperglycemic and control animals (P<0.05). Some of these parameters were ameliorated by repaglinide treatment. In diabetic rabbits treated with repaglinide, protein oxidation was diminished by 17.8% after 8 weeks of experiment. The level of AA in plasma of diabetic treated animals was higher than in non-treated diabetic groups (by 9.4 and 22.6% after 4 and 8 weeks, respectively). In diabetic treated animals, the TAS level was also significantly increased (by 23.6 and 16.7%). However, in diabetic rabbits, repaglinide did not affect the concentration of IL-6.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Ascorbic Acid; Blood Glucose; Carbamates; Diabetes Mellitus, Experimental; Hypoglycemic Agents; Insulin; Piperidines; Rabbits

Gastroretentive dosage forms have potential for use as controlled-release drug delivery systems. Multiple unit systems avoid the 'all-or-none' gastric emptying nature of single-unit systems. A controlled release system designed to increase its residence time in the stomach without contact with the mucosa was achieved through the preparation of floating microspheres by the emulsion solvent diffusion technique consisting of (i) calcium silicate (FLR) as porous carrier; (ii) repaglinide, an oral hypoglycemic agent; and (iii) Eudragit S as polymer. The effect of various formulation and process variables on the internal and external particle morphology, micromeritic properties, in vitro floating behavior, physical state of the incorporated drug, drug loading and in vitro drug release were studied. The microparticles were found to be regular in shape and highly porous. The release rate was determined in simulated gastro-intestinal fluids at 37 degrees C. The formulation demonstrated favorable in vitro floating and release characteristics. The drug encapsulation efficiency was high. Incorporation of FLR in the microspheres proved to be an effective method to achieve the desired release behavior and buoyancy. The designed system, combining excellent buoyant ability and suitable drug release pattern, could possibly be advantageous in terms of increased bioavailability of repaglinide.

Topics: Algorithms; Biological Availability; Calcium Compounds; Calorimetry, Differential Scanning; Carbamates; Drug Carriers; Drug Delivery Systems; Half-Life; Hypoglycemic Agents; Microscopy, Electron, Scanning; Microspheres; Particle Size; Piperidines; Silicates; Solubility; Temperature

The aim of this study was to analyze the antioxidative effect of repaglinide in the heart of alloxan-induced diabetic rabbits. The activities of superoxide dismutase (Cu,Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), glutathione (GSH), ascorbic acid (AA), products of lipid peroxidation (LPO) and protein carbonyl groups (PCG) were estimated after 4 and 8 weeks of repaglinide treatment (1 mg daily). At significance level p<0.05, in diabetic heart the activities of Cu,Zn-SOD and CAT were elevated as compared to control values (by 60.7% and 55.3% for Cu,Zn-SOD, and by 89.7% and 77.4% for CAT after 4 and 8 weeks, respectively). The level of AA was diminished by 52.5% and 41.5% while GSH-Px and GSSG-R activities were decreased after 4 weeks of experiment (by 11.5% and 14.4%, respectively). GSH level was diminished by 33.2% after 8 weeks. Simultaneously, in diabetic heart the levels of LPO and PCG were elevated as compared to control values (by 51.6% and 111.3% for LPO, and by 72.0% and 132.9% for PCG after 4 and 8 weeks, respectively). In diabetic animals, repaglinide normalized GSH-Px activity and GSH level. It modified the activities of Cu,Zn-SOD, CAT and AA as compared to diabetic non-treated animals. In diabetic-treated rabbits the level of LPO was diminished as compared to diabetic non-treated animals, while the level of PCG was not affected. In the present study, repaglinide did not affect blood glucose and plasma insulin concentrations in diabetic rabbits. Nevertheless, the drug showed some beneficial antioxidative properties in the heart tissue.

Topics: Alloxan; Animals; Antioxidants; Blood Glucose; Carbamates; Diabetes Mellitus, Experimental; Insulin; Male; Myocardium; Oxidative Stress; Piperidines; Rabbits

Repaglinide is an antidiabetic drug metabolised by cytochrome P450 (CYP) 2C8 and CYP3A4 enzymes. To clarify the mechanisms of observed repaglinide drug interactions, we determined the contribution of the two enzymes to repaglinide metabolism at different substrate concentrations, and examined the effect of fibrates and rifampicin on CYP2C8, CYP3A4 and repaglinide metabolism in vitro. We studied repaglinide metabolism using pooled human liver microsomes, recombinant CYP2C8 and recombinant CYP3A4 enzymes. The effect of quercetin and itraconazole on repaglinide metabolism, and of gemfibrozil, bezafibrate, fenofibrate and rifampicin on CYP2C8 (paclitaxel 6alpha-hydroxylation) and CYP3A4 (midazolam 1-hydroxylation) activities and repaglinide metabolism were studied using human liver microsomes. At therapeutic repaglinide concentrations (<0.4 microM), CYP2C8 and CYP3A4 metabolised repaglinide at similar rates. Quercetin (25 microM) and itraconazole (3 microM) inhibited the metabolism of 0.2 microM repaglinide by 58% and 71%, and that of 2 microM repaglinide by 56% and 59%, respectively. The three fibrates inhibited CYP2C8 (Ki: bezafibrate 9.7 microM, gemfibrozil 30.4 microM and fenofibrate 92.6 microM) and repaglinide metabolism (IC50: bezafibrate 37.7 microM, gemfibrozil 111 microM and fenofibrate 164 microM), but had no effect on CYP3A4. Rifampicin inhibited CYP2C8 (Ki 30.2 microM), CYP3A4 (Ki 18.5 microM) and repaglinide metabolism (IC50 13.7 microM). In conclusion, both CYP2C8 and CYP3A4 are important in the metabolism of therapeutic concentrations of repaglinide in vitro, but their predicted contributions in vivo are highly dependent on the scaling factor used. Gemfibrozil is only a moderate inhibitor of CYP2C8 and does not inhibit CYP3A4; inhibition of CYP-enzymes by parent gemfibrozil alone does not explain its interaction with repaglinide in vivo. Rifampicin competitively inhibits both CYP2C8 and CYP3A4, which can counteract its inducing effect in humans.

Topics: Aryl Hydrocarbon Hydroxylases; Bezafibrate; Carbamates; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drug Interactions; Fenofibrate; Gemfibrozil; Humans; Hypoglycemic Agents; In Vitro Techniques; Itraconazole; Microsomes, Liver; Midazolam; Paclitaxel; Piperidines; Quercetin; Rifampin

Type 2 diabetes mellitus is a chronic disease with potentially devastating long-term complications. Despite the tremendous body of research and experience in the adult population, relatively little is established regarding this condition and its optimal management in children and adolescents. The pediatric community awaits results of ongoing trials as well as further study of optimal intervention in children, as they continue to extrapolate management practices from their adult counterparts.

Topics: Administration, Oral; Adolescent; Carbamates; Child; Clinical Trials as Topic; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Metformin; Piperidines; Sulfonylurea Compounds; Thiazolidinediones; Treatment Outcome

To design and synthesize new compounds of prandial glucose regulator with more simple structure.. The target compounds were synthesized from diethyl succinate and benzaldehyde or 4-fluorobenzaldehyde by four-step reactions. Thus 18 compounds were synthesized. Their structures were comfirmed by NMR, MS and IR.. Seventeen compounds had different hypoglycemic activity in mice, among them, 9 compounds had higher hypoglycemic activity and 6 compounds had character of prandial glucose regulator.. Part of the compounds have higher hypoglycemic activity deserve to be further investigated.

Topics: Animals; Benzylidene Compounds; Blood Glucose; Carbamates; Cyclohexanes; Hypoglycemic Agents; Indoles; Isoindoles; Mice; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Structure-Activity Relationship; Succinates

Type 2 diabetes mellitus is the consequence of both insulin resistance and impaired insulin secretion. In the progression from normal glucose tolerance to diabetes, postprandial glucose (PPG) levels often rise before fasting plasma glucose (FPG) levels increase above 126 mg/dL (7.0 mmol/L). Numerous epidemiologic studies have shown that impaired glucose tolerance is associated with increased risk for macrovascular disease and that isolated postchallenge hyperglycemia is an independent factor for increased mortality. Reducing the risk for microvascular complications by improving glycosylated hemoglobin (HbA(1c)) levels is well documented. Emerging data now support the relationship between glycemic control and macrovascular disease. Epidemiologic studies documenting postprandial hyperglycemia and the risk for increased mortality suggest that lowering PPG levels might be beneficial. Optimizing both FPG and PPG is important in achieving normal/near-normal glucose levels. Many patients with type 2 diabetes have difficulty attaining the recommended HbA(1c) goal despite normal/near-normal FPG levels; thus, pharmacologic treatment targeting PPG levels may prove beneficial.

Topics: Antihypertensive Agents; Blood Glucose; Blood Glucose Self-Monitoring; Carbamates; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Disease Progression; Drug Therapy, Combination; Glyburide; Glycated Hemoglobin; Glycoside Hydrolase Inhibitors; Humans; Hyperglycemia; Hypoglycemic Agents; Metformin; Piperidines; Postprandial Period

Several lines of evidence support the hypothesis that ATP-sensitive K+ channels (K+(ATP)) participate in the brain's regulation of peripheral glucose homeostasis. In testing this hypothesis we conducted a series of in vivo experiments using albino rats and bilateral intrahypothalamic injections of K+(ATP) channel blockers, glibenclamide and repaglinide. The results show that 0.2 and 2.0 nM injections of glibenclamide lowered blood glucose in a dose-dependent manner. During mild insulin-induced hypoglycemia, hypothalamic glibenclamide delayed recovery to normoglycemia. The impaired recovery was associated with a reduction in plasma norepinephrine (P<0.001), though circulating epinephrine and glucagon were not reduced. In a separate experiment, 2-deoxy-D-glucose (200 mg/kg) was intraperitoneally administered to produce neuroglucopenia. Hypothalamic injections of either glibenclamide or repaglinide significantly blunted compensatory hyperglycemic responses (P<0.01). In a feeding study, 2.0, but not 0.2 nM of hypothalamic glibenclamide, reduced chow intake over a 2-h period (P<0.01). The results support the hypothesis that hypothalamic K+(ATP) channels participate in central glucose-sensing and glucose regulation.

Topics: Animals; Blood Glucose; Carbamates; Chromatography, High Pressure Liquid; Epinephrine; Glucagon; Glyburide; Homeostasis; Hypoglycemic Agents; Hypothalamus; Male; Norepinephrine; Piperidines; Potassium Channel Blockers; Potassium Channels; Rats; Rats, Sprague-Dawley

The effects of the angiotensin-converting enzyme (ACE) inhibitor monopril and the angiotensin II receptor blocker losartan on serum glucose, protein levels and some serum lipid components were compared in normal and diabetic rats receiving oral antidiabetic drugs 'repaglinide or gliclazide'. The two antihypertensive agents, when administered concurrently with oral hypoglycemic agents 'repaglinide or gliclazide' in normal and diabetic rats exerted a significant hypoglycemic effect. Serum protein levels were mainly unaffected by the two antihypertensive drugs. Monopril and losartan exhibit a hypolipidemic effect in normal and diabetic rats when administered in combination with oral hypoglycemic agents 'gliclazide or repaglinide'. Monopril or losartan when used alone exerted insignificant effect in high density lipoprotein (HDL) in normal rats, while in combination with gliclazide or repaglinide caused a significant increase in HDL in normal rats. Concomitantly, monopril or losartan, when administered alone or in combination with repaglinide or gliclazide in diabetic rats exerted a significant increase in serum HDL. On the other hand, all the investigated drugs showed a significant decrease in serum low density lipoprotein (LDL) in normal and diabetic rats.

Topics: Alloxan; Animals; Blood Glucose; Blood Proteins; Carbamates; Cholesterol, LDL; Diabetes Mellitus, Experimental; Disease Models, Animal; Drug Therapy, Combination; Egypt; Fosinopril; Gliclazide; Hyperlipidemias; Hypolipidemic Agents; Lipids; Losartan; Male; Piperidines; Rats; Rats, Sprague-Dawley; Triglycerides

18F-labeled non-sulfonylurea hypoglycemic agent (S)-2-(2-[(18)F]fluoroethoxy)-4-((3-methyl-1-(2-piperidin-1-yl-phenyl)-butylcarbamoyl)-methyl)-benzoic acid ([(18)F]repaglinide), a derivative of the sulfonylurea-receptor (SUR) ligand repaglinide, was synthesized as a potential tracer for the non-invasive investigation of the sulfonylurea 1 receptor status of pancreatic beta-cells by positron emission tomography (PET) in the context of type 1 and type 2 diabetes. [(18)F]Repaglinide could be obtained in an overall radiochemical yield (RCY) of 20% after 135 min with a radiochemical purity higher than 98% applying the secondary labeling precursor 2-[(18)F]fluoroethyltosylate. Specific activity was in the range of 50-60 GBq/micromol. Labeling was conducted by exchanging the ethoxy-moiety into a 2-[(18)F]fluoroethoxy group. To characterize the properties of fluorinated repaglinide, the affinity of the analogous non-radioactive (19)F-compound for binding to the human SUR1 isoform was assessed. [(19)F]Repaglinide induced a complete monophasic inhibition curve with a Hill coefficient close to 1 (1.03) yielding a dissociation constant (K(D)) of 134 nM. Biological activity was proven via insulin secretion experiments on isolated rat islets and was comparable to that of repaglinide. Finally, biodistribution of [(18)F]repaglinide was investigated in rats by measuring the concentration of the compound in different organs after i.v. injection. Pancreatic tissue displayed a stable accumulation of approximately 0.12% of the injected dose from 10 min to 30 min p.i. 50% of the radioactive tracer could be displaced by additional injection of unlabeled repaglinide, indicating that [(18)F]repaglinide might be suitable for in vivo investigation with PET.

Topics: Animals; ATP-Binding Cassette Transporters; Carbamates; Feasibility Studies; Fluorine Radioisotopes; Islets of Langerhans; Isotope Labeling; Metabolic Clearance Rate; Multidrug Resistance-Associated Proteins; Organ Specificity; Piperidines; Positron-Emission Tomography; Potassium Channels, Inwardly Rectifying; Radiopharmaceuticals; Rats; Rats, Inbred Lew; Rats, Sprague-Dawley; Receptors, Drug; Sulfonylurea Receptors; Tissue Distribution

Taurine has been found to inhibit ATP-sensitive K+ (KATP) channels in rat pancreatic beta-cells [Park et al., Biochem Pharmacol 2004;67:1089-1096] which could be due to its interaction with a benzamido-binding site on SUR1. In present study, we further evaluated the mechanism of taurine action on the KATP-channel inhibition, using cloned KATP-channels with different types of SUR subunit expressed in Xenopus laevis oocytes. The oocytes were coinjected with Kir6.2 mRNA, and mRNA encoding SUR1, SUR2A or SUR2B. Macroscopic currents were recorded from giant excised inside-out patches. The binding of glibenclamide to SUR1 was assessed by using a glibenclamide-fluorescent probe. Intracellular taurine inhibited all three types of KATP-channels to a similar extent. They were fit to the Hill equation, showing IC50 of 11.0 mM for Kir6.2/SUR1, 10.9 mM for Kir6.2/SUR2A, and 9.0 mM for Kir6.2/SUR2B currents. Taurine at the concentration of 10 mM enhanced the high-affinity bindings of glibenclamide and repaglinide on all types of SUR, whereas the low-affinity binding on Kir6.2 was not affected. The intensity of glibenclamide fluorescence was higher in the plasma membrane of taurine-pretreated oocytes. The high-affinity binding of tolbutamide or gliclazide on SUR was not modified by taurine. These results suggest that the taurine inhibition of KATP-channels is mediated by an interaction with the site on SUR where the benzamido group is bound. Therefore, intracellular concentrations of taurine in different tissues may be more important in determining taurine modulation of the KATP-channel rather than distinct types of SUR subunit.

Topics: Animals; ATP-Binding Cassette Transporters; Carbamates; Drug Interactions; Female; Gene Expression; Gliclazide; Glyburide; Hypoglycemic Agents; Membrane Proteins; Mice; Oocytes; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Protein Subunits; Rats; Receptors, Drug; Sulfonylurea Receptors; Taurine; Tolbutamide; Xenopus laevis

As an example application of the CORE Diabetes Model in type 2 diabetes, we simulated the cost-effectiveness of repaglinide/metformin combination therapy versus nateglinide/metformin for treatment of individuals with type 2 diabetes with an inadequate response to sulphonylurea, metformin, or fixed dose glyburide/metformin.. The CORE Diabetes Model was used to simulate long-term outcomes for a cohort of individuals with type 2 diabetes treated with either repaglinide/metformin or nateglinide/metformin. HbA1c changes for each regimen were taken from a comparative study. At the end of the study, changes in HbA1c from baseline were -1.28% points and -0.67% points for repaglinide/metformin and nateglinide/metformin, respectively. Median final doses were 5.0 mg/day for repaglinide, 360 mg/day for nateglinide and 2000 mg/day metformin in each treatment arm. Costs were calculated as the annual costs for drugs plus costs of complications (US Medicare perspective) over a 30-year period. Life expectancy (LE) and quality-adjusted life expectancy (QALE) were calculated. Outcomes and costs were discounted at 3% annually.. With repaglinide/metformin, improved glycaemic control led to projected decreases in complication rates, improvement of LE and QALE by 0.15 and 0.14 years respectively, and total cost savings of 3,662 dollars/person over the 30-year period. Repaglinide/metformin had a 96% probability that the incremental costs per quality-adjusted life year gained would be 20,000 dollars or less, and a 66% probability that repaglinide/metformin would be cost-saving compared to nateglinide/metformin. Sensitivity analyses supported the validity and reliability of the results.. In the health economic context, repaglinide/metformin combination was dominant to nateglinide/metformin. The CORE Diabetes Model is a tool to help third-party reimbursement payers identify treatments for type 2 diabetes that are good value for money.

Topics: Carbamates; Cohort Studies; Computer Simulation; Cost of Illness; Cost-Benefit Analysis; Cyclohexanes; Decision Support Systems, Clinical; Diabetes Complications; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Health Care Costs; Humans; Male; Metformin; Middle Aged; Models, Econometric; Nateglinide; Outcome Assessment, Health Care; Phenylalanine; Piperidines; Quality-Adjusted Life Years

The 11C-labeled sulfonylurea receptor 1 (SUR1) ligand (S)-2-([11C]methoxy)-4-[3-methyl-1-(2-piperidine-1-yl-phenyl)-butyl-carbamoyl]-benzoic acid ([11C]methoxy-repaglinide) was synthesized in an overall radiochemical yield of 35% after 55 min with a radiochemical purity higher than 99%. This compound is considered for the noninvasive investigation of the SUR1 receptor status of pancreatic beta-cells by positron emission tomography (PET) in the context of type 1 and type 2 diabetes. The specific activity was 40-70 GBq/micromol. In vitro testing of the nonradioactive methoxy-repaglinide was performed to characterize the affinity for binding to the human SUR1 isoform. Methoxy-repaglinide induced a complete monophasic inhibition curve with a Hill coefficient close to 1 (1.03) yielding a dissociation constant (KD) of 83 nM and an IC50 of 163 nM. Insulin secretion experiments on isolated rat islets were performed to prove biological activity, which was determined to be in the same range as that of original repaglinide.

Topics: Animals; ATP-Binding Cassette Transporters; Benzoates; Binding, Competitive; Carbamates; Carbon Radioisotopes; COS Cells; Humans; Hydroxybenzoate Ethers; In Vitro Techniques; Insulin; Insulin Secretion; Islets of Langerhans; Piperidines; Positron-Emission Tomography; Potassium Channels; Potassium Channels, Inwardly Rectifying; Radiopharmaceuticals; Rats; Receptors, Drug; Stereoisomerism; Sulfonylurea Receptors

Diabetes mellitus is a complex disorder of the energy metabolism. In the present paper, we have tried to illustrate the changes in the regulation of blood glucose levels encountered in the two main types of diabetes: Type 2 (T2DM) and Type 1 (T1DM) diabetes mellitus, compared with healthy, non-diabetic subjects. For this we used the MiniMed CGMS (Continuous Glucose Monitoring System) which allows the continuous in vivo blood glucose measurement over a 3-day period. The study group comprised 19 diabetic patients (14 T1DM and 5 T2DM cases) and 4 non-diabetic controls. The recording in normal subjects showed a glycemic variation between 46 and 118 mg/dl, suggesting the existence of a strong and efficient glycemic control mechanism. In T2DM patients, both on diet only or on oral antidiabetic treatment, the oscillation of blood glucose levels was significantly higher compared to that recorded in non-diabetic subjects. In T1DM patients with stable metabolic control blood glucose fluctuations were comparable with those recorded in long-term type 2 diabetic patients but the "mean" values of blood glucose over 72 hours were lower. The CGMS is a valuable tool in the detection of unrecognized hypoglycemic episodes and hyperglycemic postprandial peaks and allows the patient and the health care team to adjust the treatment regimen in order to improve glycemic control. From our point of view, the CGMS could offer valuable information for the knowledge of glycemic regulation in normal people and for the diabetogenic mechanisms in prediabetic IGT and IFG patients.

Topics: Adolescent; Adult; Biomarkers; Blood Glucose; Blood Glucose Self-Monitoring; Carbamates; Circadian Rhythm; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Monitoring, Physiologic; Piperidines; Postprandial Period; Statistics as Topic; Treatment Outcome

Topics: Aged; Carbamates; Chemical and Drug Induced Liver Injury; Diabetes Mellitus, Type 2; Humans; Hyperglycemia; Hypoglycemic Agents; Male; Piperidines

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Administration Schedule; Eating; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines

To evaluate the accuracy of nocturnal continuous glucose monitoring by CGMS.. A CGMS was inserted in 14 type 2 diabetic patients on combined oral and insulin therapy at altogether 15 occasions. During the second (48 hours) and third (72 hours) night of registration each subject was observed and plasma glucose was analysed seven times during the night by venous sampling and compared to CGMS. These venous values were not used for calibration of the sensor. Pairs of data were analysed using correlation coefficient, Bland-Altman graphs and Clarke Error Grid analysis.. 32% of CGMS data did not meet the quality criteria for optimal accuracy and were excluded. A correlation coefficient of 0.80 (p < 0.0001) was seen after 48 hours and a lower coefficient of 0.33 (p = 0.0082) after 72 hours. Bland-Altman analyses demonstrated that the dispersion of the values around the mean of differences was wider after 72 hours as compared to after 48 hours. In the Clark Error Grid analysis 100% of data were within zones A and B after 48 hours, with 60% in zone A. After 72 hours only 44% were in zone A and 7% of data were in the clinically unacceptable zone D.. The MiniMed Medtronic CGMS has acceptable nocturnal accuracy after 48 hours of registration, but the accuracy thereafter deteriorates with time, implicating that the CGMS thereafter may prove less useful for nocturnal monitoring.

Topics: Administration, Oral; Aged; Body Mass Index; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Middle Aged; Monitoring, Ambulatory; Monitoring, Physiologic; Piperidines; Regression Analysis; Reproducibility of Results; Time Factors

This study sought first to compare the pharmacodynamics and pharmocokinetics of two rapid-onset, rapidly-reversible insulinotropic agents, nateglinide and repaglinide, in pre-diabetic Cynomolgus monkeys and second to use these agents to assess the metabolic effects of early insulin secretion on prandial glucose control.. First, equipotent doses of nateglinide (20 mg/kg) and repaglinide (0.1 mg/kg) or vehicle were given intragastrically to overnight-fasted ketamine-anesthetized pre-diabetic Cynomolgus monkeys and samples were obtained for measurement of plasma glucose, insulin, glucagon, NEFA and drug concentrations. Second, nateglinide, repaglinide or vehicle were administered 10 min before a glucose-supplemented liquid meal and prandial glucose and insulin profiles were compared.. Although oral administration of nateglinide and repaglinide elicited similar maximum increments of plasma insulin (+403 and +448 pmol/l, respectively), the effects of nateglinide were more rapidly manifest and less prolonged. With nateglinide, insulin increased within 10 min and returned to baseline within 50 min. After repaglinide, the first increase occurred at 30 min and insulin concentrations remained increased for 3.5 h post-dose. When given 10 min before a meal, nateglinide increased early, but not total insulin release (AUC(0-210)=108 vs 150 nmol/l min for nateglinide and vehicle, respectively) and reduced prandial glucose excursions by 78%. Repaglinide increased total insulin release (AUC(0-210)=298 nmol/l min) and reduced glucose excursions by 53%.. Nateglinide is more rapid-acting and rapidly-reversible than is repaglinide. By restoring a more physiologic insulin profile, nateglinide is more effective than repaglinide in controlling prandial glucose excursions with less hyperinsulinaemia.

Topics: Animals; Blood Glucose; Carbamates; Cyclohexanes; Fatty Acids, Nonesterified; Food; Glucagon; Hypoglycemic Agents; Insulin; Insulin Secretion; Kinetics; Macaca fascicularis; Male; Nateglinide; Phenylalanine; Piperidines

Topics: Administration, Oral; Carbamates; Cyclohexanes; Diabetes Mellitus; Glipizide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Nateglinide; Phenylalanine; Piperidines; Sulfonylurea Compounds

The NCS (neuronal calcium sensor) proteins, including neurocalcins, recoverins and visinin-like proteins are members of a family of Ca2+-sensitive regulators, each with three Ca2+-binding EF-hand motifs. In plants, lily CCaMK [chimaeric Ca2+/CaM (calmodulin)-dependent protein kinase] and its PpCaMK ( Physcomitrella patens CCaMK) homologue are characterized by a visinin-like domain with three EF-hands. In the present study, in an effort to discover NCS antagonists, we screened a total of 43 compounds using Ca2+-dependent drug affinity chromatography and found that the insulinotropic agent repaglinide targets the NCS protein family. Repaglinide was found to bind to NCS proteins, but not to CaM or S100 proteins, in a Ca2+-dependent manner. Furthermore, the drug antagonized the inhibitory action of recoverin in a rhodopsin kinase assay with IC50 values of 400 microM. Moreover, repaglinide tightly bound to the visinin-like domain of CCaMK and PpCaMK in a Ca2+-dependent manner and antagonized the regulatory function of the domain with IC50 values of 55 and 4 microM for CCaMK and PpCaMK respectively. Although both repaglinide and a potent insulin secretagogue, namely glibenclamide, blocked K(ATP) channels with similar potency, glibenclamide had no antagonizing effect on the Ca2+-stimulated CCaMK and PpCaMK autophosphorylation, mediated by their visinin-like domain. In addition, a typical CaM antagonist, trifluoperazine, had no effect on the CCaMK and PpCaMK autophosphorylation. Repaglinide appears to be the first antagonist of NCS proteins and visinin-like domain-bearing enzymes. It may serve as a useful tool for evaluating the physiological functions of the NCS protein family. In addition, since repaglinide selectively targets NCS proteins among the EF-hand Ca2+-binding proteins, it is a potential lead compound for the development of more potent NCS antagonists.

Topics: Animals; Bryopsida; Calcium-Binding Proteins; Calcium-Calmodulin-Dependent Protein Kinases; Calmodulin; Carbamates; Cattle; Chromatography, Affinity; Eye Proteins; G-Protein-Coupled Receptor Kinase 1; Hippocalcin; Hypoglycemic Agents; Insulin; Lipoproteins; Nerve Tissue Proteins; Neurocalcin; Neurons; Phosphorylation; Piperidines; Protein Kinases; Receptors, Calcium-Sensing; Recoverin; Retina

To assess the short-term direct medical costs and effectiveness associated with achieving recommended glycaemic goals using commonly prescribed first-line oral antihyperglycaemic medications in type 2 diabetes mellitus.. A literature-based, decision-tree model was developed to project the number of patients achieving glycosylated haemoglobin values of <7% on oral therapies and the associated costs over a 3-year timeframe. For each first-line strategy, patients could progress to combination therapy using two or more agents prior to the introduction of insulin. The overall cost of treatment included costs (2001/2002 values; US dollars) of comprehensive medical care, laboratory tests, patient education, drug therapy, home glucose monitoring and adverse events.. At 3 years, the overall cost of treatment for the various first-line strategies was 6,106 US dollars for glipizide gastrointestinal therapeutic system, 6,727 US dollars for metformin immediate release, 6,826 US dollars for metformin extended release, 7,141 US dollars for glibenclamide (glyburide)/metformin, 7,759 US dollars for rosiglitazone and 9,298 US dollars for repaglinide. Costs of comprehensive routine medical care ranged from approximately 1,538-2,128 US dollars in year 1 and from approximately 952-1,543 US dollars in subsequent years, for controlled and uncontrolled patients, respectively. Adverse events represented <1%, and drug therapies represented approximately 50%, of the overall cost, respectively. Substantial cost differences between the strategies were seen within the first year. Regardless of first-line therapy, patients progressed quickly to combination therapies, with effectiveness among the agents being similar.. Short-term costs required to provide comprehensive diabetes care and achieve glycemic goals can be substantial. The model suggests a sulphonylurea strategy may provide similar effectiveness with cost savings over other agents and should be considered when selecting an initial drug therapy in newly diagnosed patients with type 2 diabetes mellitus.

Topics: Carbamates; Cohort Studies; Decision Trees; Diabetes Mellitus, Type 2; Direct Service Costs; Drug Costs; Drug Therapy, Combination; Glipizide; Glyburide; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Managed Care Programs; Markov Chains; Metformin; Models, Economic; Piperidines; Rosiglitazone; Thiazoles; Thiazolidinediones; United States

A retrospective database analysis compared costs among patients with type 2 diabetes receiving four antidiabetic regimens: (1) repaglinide monotherapy, (2) metformin monotherapy, (3) repaglinide and metformin in combination, or (4) metformin and glyburide in combination. Pharmacy, medical, and total costs were measured for each cohort over a nine-month period. Although not statistically significant, total adjusted costs were lowest for the repaglinide-metformin combination ($8,924), followed by metformin monotherapy ($9,448), metformin and glyburide ($9,576), and repaglinide monotherapy ($11,910). These results must be confirmed in larger populations, but they imply that differences in pharmacy costs of repaglinide-metformin therapy are offset by measurable medical cost savings.

Topics: Administration, Oral; Adolescent; Adult; Aged; California; Carbamates; Cohort Studies; Data Interpretation, Statistical; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glyburide; Health Care Costs; Humans; Hypoglycemic Agents; Insulin; Insurance Claim Review; Male; Managed Care Programs; Metformin; Middle Aged; Piperidines; Retrospective Studies

To identify the principal human cytochrome P450 (CYP) enzyme(s) responsible for the human in vitro biotransformation of repaglinide. Previous experiments have identified CYP3A4 as being mainly responsible for the in vitro metabolism of repaglinide, but the results of clinical investigations have suggested that more than one enzyme may be involved in repaglinide biotransformation.. [14C]-Repaglinide was incubated with recombinant CYP and with human liver microsomes (HLM) from individual donors in the presence of inhibitory antibodies specific for individual CYP enzymes. Metabolites, measured by high-performance liquid chromatography (HPLC) with on-line radiochemical detection, were identified by liquid chromatography-mass spectrophotometry (LC-MS) and LC-MS coupled on-line to a nuclear magnetic resonance spectrometer (LC-MS-NMR).. CYP3A4 and CYP2C8 were found to be responsible for the conversion of repaglinide into its two primary metabolites, M4 (resulting from hydroxylation on the piperidine ring system) and M1 (an aromatic amine). Specific inhibitory monoclonal antibodies against CYP3A4 and CYP2C8 significantly inhibited (> 71%) formation of M4 and M1 in HLM. In a panel of HLM from 12 individual donors formation of M4 and M1 varied from approximately 160-880 pmol min-1 mg-1 protein and from 100-1110 pmol min-1 mg-1 protein, respectively. The major metabolite generated by CYP2C8 was found to be M4. The rate of formation of this metabolite in HLM correlated significantly with paclitaxel 6alpha-hydroxylation (rs = 0.80; P = 0.0029). Two other minor metabolites were also detected. One of them was M1 and the other was repaglinide hydroxylated on the isopropyl moiety (M0-OH). The rate of formation of M4 in CYP2C8 Supersomes was 2.5 pmol min-1 pmol-1 CYP enzyme and only about 0.1 pmol min-1 pmol-1 CYP enzyme in CYP3A4 Supersomes. The major metabolite generated by CYP3A4 was M1. The rate of formation of this metabolite in HLM correlated significantly with testosterone 6beta-hydroxylation (rs = 0.90; P = 0.0002). Three other metabolites were identified, namely, M0-OH, M2 (a dicarboxylic acid formed by oxidative opening of the piperidine ring) and M5. The rate of M1 formation in CYP3A4 Supersomes was 1.6 pmol min-1 pmol-1 CYP enzyme but in CYP2C8 Supersomes it was only approximately 0.4 pmol min-1 pmol-1 CYP enzyme.. The results confirm an important role for both CYP3A4 and CYP2C8 in the human in vitro biotransformation of repaglinide. This dual CYP biotransformation may have consequences for the clinical pharmacokinetics and drug-drug interactions involving repaglinide if one CYP pathway has sufficient capacity to compensate if the other is inhibited.

Topics: Antibodies, Monoclonal; Aryl Hydrocarbon Hydroxylases; Biotransformation; Carbamates; Chromatography, High Pressure Liquid; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drug Interactions; Humans; Hypoglycemic Agents; Microsomes, Liver; Piperidines

Three unknown impurities and a byproduct in repaglinide bulk drug at levels below 0.1% (ranging from 0.05 to 0.1%) were detected by a simple isocratic reversed-phase high performance liquid chromatography (HPLC) method. These impurities were isolated from crude sample of repaglinide using reversed-phase preparative high performance liquid chromatography. Based on the spectroscopic data (IR, NMR and MS) the structures of these impurities (I, II and IV) and byproduct (III) were characterised as 4-carboxymethyl-2-ethoxy-benzoic acid (I), 4-cyclohexylaminocarbamoylmethyl-2-ethoxy-benzoic acid (II), 1-cyclohexyl-3-[3-methyl-1-(2-piperidin-1-yl-phenyl)-butyl]-urea (IV) and 1,3-dicyclohexyl urea (III), respectively. Their synthesis and formation is discussed.

Topics: Carbamates; Chromatography, High Pressure Liquid; Drug Contamination; Hypoglycemic Agents; Magnetic Resonance Spectroscopy; Mass Spectrometry; Piperidines; Spectroscopy, Fourier Transform Infrared

Topics: Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Piperidines; Treatment Outcome

Topics: Adiponectin; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Intercellular Signaling Peptides and Proteins; Nateglinide; Phenylalanine; Piperidines; Proteins; Sulfonylurea Compounds

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Metformin; Nateglinide; Phenylalanine; Piperidines

A simple, precise and rapid RP-HPLC method was developed for the determination of repaglinide in pharmaceutical dosage forms. The method was carried out on a Shim-pack, RP-C18 column using a mixture of methanol: 0.1% v/v triethylamine (pH adjusted to 7 with orthophosphoric acid) and detection was done at 235 nm using nimesulide as internal standard. The linearity range was 0.1 to 0.5 microg/ml. The intra-day and inter-day precision were in the range of 0.48 to 1.01 and 0.15 to 1.15, respectively.

Topics: Calibration; Carbamates; Chromatography, High Pressure Liquid; Hypoglycemic Agents; Pharmaceutical Preparations; Piperidines; Reproducibility of Results

Repaglinide and nateglinide represent a new class of insulin secretagogues, structurally unrelated to sulphonylureas, that were developed for the treatment of type 2 diabetes. The inhibitory effect of these drugs was investigated on recombinant wild-type and mutant Kir6.2/SUR1 channels expressed in HEK293 cells. Nateglinide and repaglinide dose-dependently inhibited whole-cell Kir6.2/SUR1 currents with half-maximal inhibitory concentration (IC(50)) values of 800 and 21 nmol/l, respectively. Mutation of serine 1237 in SUR1 to tyrosine (S1237Y) abolished tolbutamide and nateglinide block, suggesting that these drugs share a common point of interaction on the SUR1 subunit of the ATP-sensitive K(+) channel. In contrast, repaglinide inhibition was unaffected by the S1237Y mutation (IC(50) = 23 nmol/l). Radioligand binding studies revealed a single high-affinity binding site for [(3)H]repaglinide on membranes prepared from HEK293 cells expressing wild-type (equilibrium dissociation constant [K(D)] = 0.40 nmol/l) or mutant (K(D) = 0.31 nmol/l) Kir6.2/SUR1 channels. Nateglinide and tolbutamide displaced [(3)H]repaglinide binding to wild-type channels with IC(50) values of 0.7 and 26 micro mol/l, respectively, but produced <10% displacement of [(3)H]repaglinide bound to mutant channels. This is consistent with the idea that binding of nateglinide and tolbutamide, but not repaglinide, is abolished by the SUR1[S1237Y] mutation and that the binding site for repaglinide is not identical to that of nateglinde/tolbutamide. These results are discussed in terms of a conformational analysis of the drug molecules.

Topics: ATP-Binding Cassette Transporters; Binding, Competitive; Carbamates; Cell Line; Cyclohexanes; Drug Interactions; Electrophysiology; Humans; Islets of Langerhans; Nateglinide; Phenylalanine; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Receptors, Drug; Sulfonylurea Receptors; Tolbutamide

Topics: Animals; ATP-Binding Cassette Transporters; Carbamates; Gliclazide; Glyburide; Hypoglycemic Agents; Kinetics; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Protein Binding; Rats; Receptors, Drug; Spodoptera; Sulfonylurea Receptors; Tolbutamide

Good glucose control is a prerequisite for the prevention of long-term complications in type 2 diabetics. In recent years, two new groups of substances have been approved for the oral treatment of type 2 diabetes: glinides and glitazones. The former are short-acting agents that promote insulin secretion and offer an alternative to the sulfonylureas, in particular in patients with irregular eating habits and high postprandial glucose peaks. The glitazones improve one of the disorders underlying type 2 diabetes, insulin resistance. They are used in particular in patients who are inadequately controlled with a sulfonylurea or metformin and who show insulin resistance. Both groups of substances are a useful addition to the antidiabetic drug armamentarium. Endpoint studies involving these substances have, however, not yet been performed.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Insulin; Nateglinide; Phenylalanine; Pioglitazone; Piperidines; Rosiglitazone; Thiazoles; Thiazolidinediones; Treatment Outcome

We investigated the in vitro effects of therapeutical concentrations of S 21403 (a succinic acid derivative also known as KAD 1229 and mitiglinide) on insulin and glucagon secretion during a metabolic stimulus (glucose rising from 5 to 8.33 mM) or at a stable 2.22 mM glucose using the isolated perfused rat pancreas model, and we compared them with the patterns of repaglinide and glibenclamide. Control perfusions were also performed. During 8.33 mM glucose, insulin release peaked to 339.12+/-22.87 microU/ml in controls. S 21403 enhanced insulin release (first peak 413.02+/-14.90 microU/ml; P<0.03 vs. controls, P=ns vs. repaglinide, P<0.005 vs. glibenclamide). Repaglinide increased glucose-induced first peak secretion to 409.33+/-20.05 microU/ml within the eighth minute (P<0.05 vs. controls, P<0.01 vs. glibenclamide). Glibenclamide did not affect the first phase of glucose-induced insulin release (peak of 338.41+/-29.79 microU/ml) but potentiated and delayed the second phase. No drug affected glucagon release. In conclusion, S 21403 induces a faster, more physiological pattern of insulin release than the other drugs we tested.

Topics: Animals; Carbamates; Dose-Response Relationship, Drug; Glucose; Glyburide; Hypoglycemic Agents; In Vitro Techniques; Indoles; Insulin; Insulin Secretion; Isoindoles; Male; Pancreas; Piperidines; Rats; Rats, Sprague-Dawley; Time Factors

This report focuses on a 16-year-old girl afflicted with hypoglycemia after administration of medications for gastrointestinal symptoms. Repaglinide-induced hypoglycemia was suspected when a tablet of repaglinide was noted in the drug package that she had been given. As the use of various types of oral hypoglycemic agents has increased, a definitive diagnosis of drug-induced hypoglycemia has become difficult. It is dangerous for a patient to take oral hypoglycemic agents without the knowledge of hypoglycemic symptoms and initial management. We present this case and review the characteristics of repaglinide to remind physicians and pharmacists to pay more attention to this situation.

Topics: Adolescent; Carbamates; Female; Humans; Hypoglycemia; Hypoglycemic Agents; Medication Errors; Piperidines

To investigate the hormonal and cellular selectivity of the prandial glucose regulators, we have undertaken a series of experiments, in which we characterised the effects of repaglinide and nateglinide on ATP-sensitive potassium ion (KATP) channel activity, membrane potential and exocytosis in rat pancreatic alpha-cells and somatotrophs. We found a pharmacological dissociation between the actions on KATP channels and exocytosis and suggest that compounds that, unlike repaglinide, have direct stimulatory effects on exocytosis in somatotrophs and alpha- and beta-cells, such as sulphonylureas and nateglinide, may have a clinically undesirable general stimulatory effect on cells within the endocrine system.

Topics: Animals; Carbamates; Cyclohexanes; Electrophysiology; Exocytosis; Hypoglycemic Agents; Islets of Langerhans; Membrane Potentials; Nateglinide; Phenylalanine; Piperidines; Postprandial Period; Potassium Channels; Rats

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Metformin; Nateglinide; Phenylalanine; Piperidines

Topics: Adult; Blood Glucose; Carbamates; Diabetes Mellitus, Type 1; Female; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Infectious Mononucleosis; Piperidines; Postprandial Period

Topics: Carbamates; Humans; Hyperglycemia; Hypoglycemic Agents; Piperidines

Nateglinide is a novel insulinotropic agent for the treatment of type 2 diabetes. It is a D-phenylalanine derivative, chemically distinct from repaglinide and sulphonylureas (glyburide or glimepiride). Although each agent is known to stimulate insulin release via the signaling cascade initiated by closure of ATP-dependent K+ (K(ATP)) channels in pancreatic beta-cells, the pharmacological effect of nateglinide is reportedly fast-acting, short-lasting, sensitive to ambient glucose and more resistant to metabolic inhibition. The aim of the present study was to elucidate the molecular mechanism(s) underlying the distinct properties of the insulinotropic action of nateglinide. By using the patch-clamp methods, we comparatively characterized the potency and kinetics of the effect of these agents on K(ATP) channels in rat beta-cells at normal vs. elevated glucose and under physiological condition vs. experimentally induced metabolic inhibition. Our results demonstrated that the mode of the action of nateglinide on K(ATP) current was unique in (a) glucose dependency; (b) increased potency and efficacy under ATP depletion and uncoupling of mitochondrial oxidative phosphorylation than physiological condition; (c) substantially more rapid onset and offset kinetics. The data provide mechanistic rationale for the unique in vivo and ex vivo activity profile of nateglinide and may contribute to reduced hypoglycemic potential associated with excessive insulin secretion.

Topics: Adenosine Triphosphate; Animals; Carbamates; Cyclohexanes; Dose-Response Relationship, Drug; Glucose; Glyburide; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Kinetics; Male; Membrane Potentials; Nateglinide; Phenylalanine; Piperidines; Potassium Channel Blockers; Potassium Channels; Rats; Rats, Sprague-Dawley; Sulfonylurea Compounds; Time Factors

GH causes insulin resistance, impairs glycemic control and increases the risk of vascular diabetic complications. Sulphonylureas stimulate GH secretion and this study was undertaken to investigate the possible stimulatory effect of repaglinide and nateglinide, two novel oral glucose regulators, on critical steps of the stimulus-secretion coupling in single rat somatotrophs.. Patch-clamp techniques were used to record whole-cell ATP-sensitive K(+) (K(ATP)) and delayed outward K(+) currents, membrane potential and Ca(2+)-dependent exocytosis. GH release was measured from perifused rat somatotrophs.. Both nateglinide and repaglinide dose-dependently suppressed K(ATP) channel activity with half-maximal inhibition being observed at 413 nM and 13 nM respectively. Both compounds induced action potential firing in the somatotrophs irrespective of whether GH-releasing hormone was present or not. The stimulation of electrical activity by nateglinide, but not repaglinide, was associated with an increased mean duration of the action potentials. The latter effect correlated with a reduction of the delayed outward K(+) current, which accounts for action potential repolarization. The latter effect had a K(d) of 19 microM but was limited to 38% inhibition. When applied at concentrations similar to those required to block K(ATP) channels, nateglinide in addition potentiated Ca(2+)-evoked exocytosis 3.3-fold (K(d)=3 microM) and stimulated GH release 4.5-fold. The latter effect was not shared by repaglinide. The stimulation of exocytosis by nateglinide was mimicked by cAMP and antagonized by the protein kinase A inhibitor Rp-cAMPS.. Nateglinide stimulates GH release by inhibition of plasma membrane K(+) channels, elevation of cytoplasmic cAMP levels and stimulation of Ca(2+)-dependent exocytosis. By contrast, the effect of repaglinide was confined to inhibition of the K(ATP) channels.

Topics: Animals; Calcium; Carbamates; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyclohexanes; Delayed Rectifier Potassium Channels; Exocytosis; Growth Hormone; Growth Hormone-Releasing Hormone; Hypoglycemic Agents; Male; Membrane Potentials; Nateglinide; Patch-Clamp Techniques; Phenylalanine; Piperidines; Pituitary Gland; Potassium; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Voltage-Gated; Rats; Rats, Sprague-Dawley

Chronic exposure of pancreatic islets to sulfonylureas (SUs) is known to impair the ability of islets to respond to subsequent acute stimulation by SUs or glucose. Nateglinide (NAT) is a novel insulinotropic agent with a primarily site of action at beta-cell K(ATP) channels, which is common to the structurally diverse drugs like repaglinide (REP) and the SUs. Earlier studies on the kinetics, glucose-dependence and sensitivity to metabolic inhibitors of the interaction between NAT and K(ATP) channels suggested a distinct signaling pathways with NAT compared to REP, glyburide (GLY) or glimepiride (GLI). To obtain further evidence for this concept, the present study compared the insulin secretion in vitro from rat islets stimulated acutely by NAT, GLY, GLI or REP at equipotent concentrations during 1-hr static incubation following overnight treatment with GLY or tolbutamide (TOL). The islets fully retained the responsiveness to NAT stimulation after prolonged pretreatment with both SUs, while their acute response to REP, GLY, and GLI was markedly attenuated, confirming the desensitization of islets. The insulinotropic efficacy of NAT in islets desensitized to SUs may result from a distinct receptor/effector mechanism, which contributes to the unique pharmacological profile of NAT.

Topics: Animals; Carbamates; Cyclohexanes; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Male; Nateglinide; Phenylalanine; Piperidines; Rats; Rats, Sprague-Dawley; Sulfonylurea Compounds

Nateglinide, a novel D-phenylalanine derivative, stimulates insulin release via closure of K(ATP) channels in pancreatic beta-cell, a primary mechanism of action it shares with sulfonylureas (SUs) and repaglinide. This study investigated (1) the influence of ambient glucose levels on the insulinotropic effects of nateglinide, glyburide and repaglinide, and (2) the influence of the antidiabetic agents on glucose-stimulated insulin secretion (GSIS) in vitro from isolated rat islets. The EC50 of nateglinide to stimulate insulin secretion was 14 microM in the presence of 3 mM glucose and was reduced by 6-fold in 8 mM glucose and by 16-fold in 16 mM glucose, indicating a glucose-dependent insulinotropic effect. The actions of glyburide and repaglinide failed to demonstrate such a glucose concentration-dependent sensitization. When tested at fixed and equipotent concentrations (approximately 2x EC50 in the presence of 8 mM glucose) nateglinide and repaglinide shifted the EC50s for GSIS to the left by 1.7 mM suggesting an enhancement of islet glucose sensitivity, while glimepiride and glyburide caused, respectively, no change and a right shift of the EC50. These data demonstrate that despite a common basic mechanism of action, the insulinotropic effects of different agents can be influenced differentially by ambient glucose and can differentially influence the islet responsiveness to glucose. Further, the present findings suggest that nateglinide may exert a more physiologic effect on insulin secretion than comparator agents and thereby have less propensity to elicit hypoglycemia in vivo.

Topics: Animals; Carbamates; Cyclohexanes; Glucose; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Kinetics; Male; Nateglinide; Phenylalanine; Piperidines; Rats; Rats, Sprague-Dawley; Sulfonylurea Compounds

We report the first case of repaglinide-induced factitious hypoglycemia in a young male. This case posed a challenging diagnostic dilemma because commercial assays for repaglinide are not available. Furthermore, the patient had a series of positive diagnostic tests such as high proinsulin and localizing intra-arterial calcium stimulation suggestive of insulinoma. This case, again, demonstrates the importance of pure clinical judgment in the face of often-conflicting laboratory data in making a correct diagnosis and the requirement of definitive data for an appropriate therapeutic resolution.

Topics: Adolescent; Blood Glucose; Carbamates; Diagnosis, Differential; Fasting; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Mental Disorders; Piperidines; Poisoning

Topics: Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Pioglitazone; Piperidines; Thiazoles; Thiazolidinediones

Topics: Carbamates; Diabetes Mellitus, Type 2; Diet, Diabetic; Feeding Behavior; Humans; Hypoglycemic Agents; Patient Compliance; Piperidines

Abnormal beta-cell function, characterized as the inability of the beta-cell to mount a rapid secretory response to glucose, is a well-established pathology of type 2 diabetes mellitus. These studies were designed to demonstrate the importance of early insulin release on the control of meal-induced glucose excursions by capitalizing on the significant pharmacodynamic differences between several oral insulin secreting agents.. Male Sprague Dawley fitted with indwelling jugular cannulas were used to compare the pharmacodynamic profiles of nateglinide (Nateg), glipizide (Glip) and repaglinide (Repag) through frequent blood samples following the administration of these compounds via oral gavage. In similar animals which were pretrained to consume their daily food intake in two discrete 45-min meals, the effects of compound induced changes in pre-meal, meal and post-meal insulin profiles on glycaemic control were assessed through frequent blood sampling following the administration of these compounds 10 min prior to a 30-min meal.. There were significant pharmacodynamics differences between the three oral agents tested and the time to elicit peak insulin secretory responses increased from Nateg (4 min) to Repag (10 min) to Glip (45 min). During the meal tolerance test, glibenclamide did not increase pre-meal insulin levels and glucose excursions paralleled those in the control. Conversely, the other three agents, at doses that produced hypoglycaemic responses of similar magnitude, all increased early insulin release (Delta AUC(-15 to 3 min) = 0.5 +/- 0.01, 1.6 +/- 0.4, 3.6 +/- 0.0, 1.2 +/- 0.1 and 1.73 +/- 0.4 nmol/min, for control, Nateg at 60 and 120 mg/kg, Glip and Repag, respectively) and curbed glucose excursions during the meal at varying rates and degrees (Delta AUC(0--30 min) = 39 +/- 6, 8 +/- 7, 5 +/- 7, - 1 +/- 8 and - 3 +/- 8 mmol/min for control, Nateg at 60 and 120 mg/kg, Glip and Repag, respectively). However, unlike Nateg, the longer duration of action of Repag and Glip elicited sustained post-meal relative hypoglycaemia.. These data support the impact of early and rapid insulin release in the control of prandial and post-meal glycaemia and demonstrate that a short anticipatory burst of insulin, restricted to the beginning of a meal, provides a clear metabolic advantage and prevents post-meal hypoglycaemic episodes when compared to a greater but reactive insulin exposure that follows a meal-induced increase in glucose excursion.

Topics: Animals; Blood Glucose; Carbamates; Cyclohexanes; Food; Glipizide; Glucagon; Insulin; Insulin Secretion; Male; Nateglinide; Phenylalanine; Piperidines; Rats; Rats, Sprague-Dawley

Topics: Carbamates; Diabetes Mellitus, Type 2; Half-Life; Humans; Hypoglycemic Agents; Insulin; Piperidines; Structure-Activity Relationship

The carbamoylbenzoic acid derivative repaglinide is a potent short-acting insulin secretagogue that acts by closing ATP-sensitive potassium (KATP) channels in the plasma membrane of the pancreatic beta cell. In this paper we investigated. the specificity of repaglinide for three types of cloned (KATP) channel composed of the inwardly rectifying potassium channel Kir6.2 and either the sulphonylurea receptor SUR1, SUR2A or SUR2B, corresponding to the beta cell, cardiac and either smooth muscle types of KATP channel, respectively.. The action of the drug was studied by whole-cell current recordings of KATP channels expressed either in Xenopus oocytes or mammalian cells (HEK293). We also used inside-out macropatches excised from Xenopus oocytes for detailed analysis of repaglinide action.. The drug blocked all three types of KATP channel with similar potency, by interacting with a low-affinity site on the pore-forming subunit of the channel (Kir6.2: half-maximal inhibition 230 micromol/l) and with a high-affinity site on the regulatory subunit, the sulphonylurea receptor (SUR: half-maximal inhibition 2-8 nmol/l). There was no difference in potency between channels containing SUR1, SUR2A or SUR2B. MgADP potentiated the inhibitory effect of repaglinide on Kir6.2/SUR1 and (to a lesser extent) Kir6.2/SUR2B, but not on Kir6.2/SUR2A.. Repaglinide interacts with a site common to all three types of sulphonylurea receptor leading to inhibition of the KATP channel. The fact that MgADP potentiated this effect in the case of the beta cell, but not cardiac, type of channel could help explain why the drug shows no adverse cardiovascular side-effects in vivo.

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Animals; ATP-Binding Cassette Transporters; Carbamates; Cell Line; Cloning, Molecular; Drug Synergism; Electric Conductivity; Female; Humans; Islets of Langerhans; Mice; Muscle, Smooth; Myocardium; Oocytes; Piperidines; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Inwardly Rectifying; Rats; Receptors, Drug; Sulfonylurea Receptors; Xenopus laevis

Topics: 1-Deoxynojirimycin; Acarbose; Carbamates; Diabetes Mellitus, Type 2; Glucosamine; Humans; Hypoglycemic Agents; Imino Pyranoses; Multicenter Studies as Topic; Pioglitazone; Piperidines; Randomized Controlled Trials as Topic; Thiazoles; Thiazolidinediones

Clinical trials provide information regarding the safety and efficacy of medications used to manage type 2 diabetes but do not elucidate drug effectiveness in a typical managed care environment. The aim of this study was to characterize "real-world" drug utilization patterns from both a prescriber and a patient perspective.. We conducted a retrospective analysis of a large administrative pharmacy claims database, using data on continuously pharmacy benefit-eligible members prescribed oral hypoglycemic agents (OHAs).. The 12-month persistence rate for the OHA cohort was low, ranging from 31% for alpha-glucosidase inhibitors to 60% for metformin; compliance rates varied between 70 and 80%. During the first 12 months of therapy, 36% of the patients remaining on therapy at 12 months had one or more therapy modifications. The mean number of therapy changes increased with the length of patient follow-up, with more than half of all patients experiencing at least one therapy change over the duration of follow-up.. These findings document the wide variation in utilization patterns associated with pharmacological management of type 2 diabetes, suggesting that opportunity exists to optimize its pharmacological management.

Topics: Carbamates; Chromans; Cohort Studies; Databases as Topic; Diabetes Mellitus, Type 2; Enzyme Inhibitors; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Insurance, Pharmaceutical Services; Longitudinal Studies; Managed Care Programs; Metformin; Piperidines; Retrospective Studies; Sulfonylurea Compounds; Thiazoles; Thiazolidinediones; Time Factors; Troglitazone; United States

Repaglinide (NovoNorm) is an antidiabetic oral agent of the new glinide class with insulinotropic activity. Its action on insulin secretion is more rapid and shorter than that of sulphonylurea compounds. Thanks to these properties, repaglinide is able to better control postprandial hyperglycaemia and is associated with a lower risk of delayed hypoglycaemic episodes. It is indicated for the treatment of type 2 (non-insulin-dependent) diabetes mellitus as monotherapy, after diet failure, or in combination with metformin, when the biguanide is insufficient. NovoNorm is commercialized as tablets of 0.5, 1 and 2 mg, to be taken just before each meal. Initial dosis should be 0.5 mg before meal in diabetic patients on diet alone or 1 mg before meal in patients already receiving an hypoglycaemic agent. If necessary, the dosis should be progressively increased, depending on the individual response, up to 4 mg before meal (maximal daily dosage of 16 mg), in order to optimize blood glucose control.

Topics: Administration, Oral; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Humans; Hypoglycemic Agents; Piperidines; Postprandial Period

Novel insulinotropic agent nateglinide stimulates insulin via binding to sulfonylurea receptor and closing the ATP-dependent K+ (K(ATP)) channels in pancreatic beta-cells, leading to an increase in [Ca(2+)](i) for exocytosis. The voltage-dependent Ca(2+) channel and the delayed rectifier K+ (Kv) channels are also present in beta-cells and their activities determine the configuration of action potential and hence contribute to the regulation of [Ca(2+)](i) and insulin secretion. This study, by using the patch-clamp method in whole cell configuration, comparatively characterized the direct effects of sulfonylurea receptor ligands including nateglinide, glyburide, and repaglinide on Kv and Ca(2+) channels. Each agent inhibited Kv currents in a concentration-dependent manner with effective concentration range two to three orders higher than that for blocking K(ATP) channels. A marginal stimulation of Ca(2+) current was observed with all drugs, while repaglinide at concentration greater than 300 nM inhibited Ca(2+) current. The direct effects of these antidiabetic agents on Kv and Ca(2+) channels may act concertedly with their primary action on K(ATP) channels in regulating [Ca(2+)](i) and the stimulus-secretion coupling.

Topics: Animals; Calcium Channels; Carbamates; Cyclohexanes; Dose-Response Relationship, Drug; Electric Stimulation; Glyburide; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Male; Membrane Potentials; Nateglinide; Patch-Clamp Techniques; Phenylalanine; Piperidines; Potassium Channels; Rats; Rats, Sprague-Dawley

Insulin and glucose levels in response to premeal insulin lispro or repaglinide were evaluated in adult patients with cystic fibrosis-related diabetes (CFRD) without fasting hyperglycemia.. Seven patients with CFRD were fed 1,000-kcal liquid mixed meals. Three study conditions were administered in random order on separate mornings: 1) no premeal diabetes medication, 2) insulin lispro, 0.1 unit/kg body wt premeal and 3) repaglinide 1 mg premeal. Glucose and insulin levels were measured every 20 min for 5 h.. Fasting insulin and glucose levels were normal in patients with CFRD, but the peak glucose level was elevated. Insulin lispro significantly decreased the peak glucose level (P = 0.0004) and the 2-h (P = 0.001) and 5-h (P < 0.0001) glucose area under the curve (AUC). Repaglinide significantly decreased the 5-h glucose AUC (P = 0.03). Neither drug completely normalized cystic fibrosis glucose excursion at the doses used for this study. Insulin lispro significantly increased the 5-h insulin AUC (P = 0.04).. In response to subcutaneous insulin lispro, postprandial glucose excursion was significantly diminished and insulin secretion was enhanced compared with a control meal in which no medication was given to patients with CFRD. The oral agent repaglinide resulted in lesser corrections in these parameters. Neither drug completely normalized glucose or insulin levels, suggesting that the doses chosen for this study were suboptimal. Placebo-controlled longitudinal studies comparing the effectiveness of repaglinide and insulin on glucose metabolic control as well as overall nutrition and body weight are needed to help determine optimal medical treatment of CFRD.

Topics: Adult; Blood Glucose; Carbamates; Cystic Fibrosis; Diabetes Mellitus; Female; Food; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Lispro; Male; Piperidines

Topics: Aged; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Humans; Hypoglycemic Agents; Insulin, Isophane; Male; Middle Aged; Piperidines

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Drug Administration Schedule; Humans; Piperidines; Postprandial Period

Topics: Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug Administration Schedule; Humans; Hypoglycemic Agents; Piperidines

Drug interaction studies were carried out to ensure that hypoglycemia due to inhibition of repaglinide elimination or chronic hyperglycemia due to inhibition of repaglinide absorption was avoided. Conversely, the effects of repaglinide on the pharmacokinetics of drugs with only a narrow margin between effective and toxic concentrations, such as digoxin or theophylline, were determined. The studies reported here compared monotherapy with combined therapies in healthy volunteers. There were no significant differences between the pharmacokinetic parameters of repaglinide when given as monotherapy and when administered concurrently with cimetidine. Similarly, the coadministration of repaglinide and digoxin did not influence the pharmacokinetics of digoxin administered alone. When repaglinide was coadministered with theophylline, the only pharmacokinetic change was that the peak plasma theophylline concentration was slightly reduced. No direct drug-drug interactions were found in these studies, suggesting that repaglinide may be coprescribed with cimetidine, digoxin, or theophylline at the dosage used for monotherapy.

Topics: Adolescent; Adult; Carbamates; Cimetidine; Cross-Over Studies; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Digoxin; Drug Interactions; Female; Humans; Hypoglycemic Agents; Male; Middle Aged; Mixed Function Oxygenases; Piperidines; Theophylline

Repaglinide is a novel oral antidiabetic agent, marking the development of a new class of drugs for type 2 diabetes. This article examines repaglinide and its position in the treatment of type 2 diabetes.

Topics: Administration, Oral; Blood Glucose; Body Weight; Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemia; Hypoglycemic Agents; Piperidines; Sulfonylurea Compounds

Nateglinide (A-4166) is an amino acid derivative with insulinotrophic action in clinical development for treatment of type 2 diabetes. The aim of this study was to determine whether nateglinide's interaction at the K(ATP) channel/sulfonylurea receptor underlies its more rapid onset and shorter duration of action in animal models. Binding studies were carried out with membranes prepared from RIN-m5F cells and HEK-293 cells expressing recombinant human sulfonylurea receptor 1 (SUR1). The relative order for displacement of [(3)H]glibenclamide in competitive binding experiments with RIN-m5F cell membranes was glibenclamide > glimepiride > repaglinide > glipizide > nateglinide > L-nateglinide > tolbutamide. The results with HEK-293/recombinant human SUR1 cells were similar with the exception that glipizide was more potent than repaglinide. Neither nateglinide nor repaglinide had any effect on the dissociation kinetics for [(3)H]glibenclamide, consistent with both compounds competitively binding to the glibenclamide-binding site on SUR1. Finally, the inability to measure [(3)H]nateglinide binding suggests that nateglinide dissociates rapidly from SUR1. Direct interaction of nateglinide with K(ATP) channels in rat pancreatic beta-cells was investigated with the patch-clamp method. The relative potency for inhibition of the K(ATP) channel was repaglinide > glibenclamide > nateglinide. Kinetics of the inhibitory effect on K(ATP) current showed that the onset of inhibition by nateglinide was comparable to glibenclamide but more rapid than that of repaglinide. The time for reversal of channel inhibition by nateglinide was also faster than with glibenclamide and repaglinide. These results suggest that the unique characteristics of nateglinide are largely the result of its interaction at the K(ATP) channel.

Topics: Animals; ATP-Binding Cassette Transporters; Binding, Competitive; Carbamates; Cell Membrane; Cell Separation; Cells, Cultured; Cyclohexanes; Glucose; Glyburide; Glycosyltransferases; Humans; Hypoglycemia; Hypoglycemic Agents; In Vitro Techniques; Insulin; Islets of Langerhans; KATP Channels; Kinetics; Male; Membrane Proteins; Nateglinide; Patch-Clamp Techniques; Phenylalanine; Piperidines; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Inwardly Rectifying; Rats; Rats, Sprague-Dawley; Repressor Proteins; Saccharomyces cerevisiae Proteins; Sulfonylurea Compounds

Repaglinide (CAS 135062-02-1), a biguanide, is an orally available insulin secretagogue (beta-cell stimulant) and has been developed for the treatment of Type II diabetes. The developmental toxicity of the compound was investigated in rats. The effects on fertility, on embryo- and fetogenesis and on peri- and postnatal development were investigated. In a 'fertility study' 24 males were treated with 0, 1, 30, 300 mg/kg for 10 weeks prior to mating and during mating, and 24 females with 0, 1, 30, 80 mg/kg for 4 weeks prior to mating until gestation day 22 (hysterectomy group) or through gestation day 22 until postnatal day, i.e. lactation day 21 (littering group). In a 'teratogenicity study' with a hysterectomy group and a littering group included, 36 females were treated with 0, 0.5, 5 and 80 mg/kg from gestation day 7-16. In a 'peri-postnatal study' with a cross-foster group included 23 females were treated in the core study with 0, 0.5, 5, 30 and 80 mg/kg from gestation day 16 to lactation day 21 and in the cross-foster group 18 females with 0 and 80 mg/kg from gestation day 16 to lactation day 21. In a 'supplementary study' with five treatment windows 13 females each were treated with 80/30 mg/kg from gestation day 1-5 (W 1), gestation day 6-16 (W 2), gestation day 17-22 (W 3), lactation day 1-14 (W 4) and lactation day 15-21 (W 5). Effects of repaglinide on fertility, implantation, early and late embryogenesis, fetogenesis, birth and postnatal development including fertility of the offspring were investigated. In the 'fertility study' the NOTEL (no toxic effect level) for males was estimated to be 1 mg/kg and for females 30 mg/kg. In the 'teratogenicity study' the maternal NOTEL was 0.5 mg/kg as it was in the 'peri-postnatal study' 5 mg/kg. Food consumption and body weight gain of females were significantly reduced at the beginning of the respective treatment periods of the 'supplementary study' indicating a strong reaction of the dams to the treatment underlined by the death of individual animals (W 3, W 4 and W 5). Offspring survival during the last trimester of pregnancy and during lactation was affected in the 'fertility study' and in the 'peri-postnatal study' after 30 and 80 mg/kg and in the 'supplementary study' slightly in W 3 and more pronounced in W 4 and W 5. Changes of the skeleton in the extremities of the offspring were observed in all studies where the animals were exposed to repaglinide during late pregnancy (i.e. after completion of or

Topics: Animals; Bone Development; Carbamates; Embryo Implantation; Embryonic and Fetal Development; Female; Fertility; Growth; Humans; Hypoglycemic Agents; Labor, Obstetric; Piperidines; Pregnancy; Rats; Rats, Wistar; Reproduction; Teratogens

This study investigated plasma protein binding by the novel oral hypoglycemic agent, repaglinide, and assessed the influence of other protein-bound drugs upon this process. Varying concentrations of [3H]-repaglinide (0.01 to 100 micrograms/ml) were incubated in solutions of plasma proteins (human serum albumin, HSA; alpha 1-acid glycoprotein, AAGP), or human plasma in the absence or presence of several test drugs. Protein binding was assessed using an ultrafiltration technique. At all concentrations tested, the mean binding of repaglinide in plasma was 98.5%, binding to HSA averaged 98.6%, and the binding to AAGP was saturable and remained below 50%. Warfarin 10 micrograms/ml, furosemide 0.2 microgram/ml, and tolbutamide 100 micrograms/ml, significantly reduced in vitro binding of repaglinide at 1 and 100 micrograms/ml versus control (p < 0.05), producing an 18-36% increase in free repaglinide. No reduction was found using 0.1 microgram/ml repaglinide. Diazepam, glibenclamide and nicardipine hydrochloride had no significant effects on the in vitro protein binding of repaglinide. These data suggest that the binding of repaglinide to HSA in human plasma has potential clinical significance, and that within the therapeutic range for repaglinide, the presence of the test drugs has no clinically relevant effects on repaglinide binding to plasma proteins.

Topics: Adsorption; Blood Proteins; Carbamates; Drug Interactions; Humans; Hypoglycemic Agents; Orosomucoid; Piperidines; Protein Binding; Serum Albumin

Repaglinide is the first stimulator of insulin secretion from the new meglitinide family. Via specific binding to the ATP-sensitive potassium channel of the beta cell membrane, it stimulates the rapid release of insulin. In preclinical studies, the insulin-stimulating effect of repaglinide has been found to be 10 to 20 times more potent than that of glibenclamide. Repaglinide is rapidly absorbed and has a short action, which makes it particularly well suited for the regulation of prandial blood glucose and meal-related dose adjustment. Since repaglinide is eliminated almost exclusively by non-renal routes, it can be used without danger in patients with moderately reduced renal function. Repaglinide is a suitable agent for first-line monotherapy in patients whose glucose metabolism cannot be optimally controlled by increasing physical activity and appropriate dietary measures. Repaglinide is clearly superior to glibenclamide in reducing postprandial hyperglycemia, and has a lower hypoglycemia risk than all the sulphonylureas. The flexibility of repaglinide makes it possible for good oral meal-related treatment.

Topics: Blood Glucose; Carbamates; Diabetes Mellitus; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug Administration Schedule; Humans; Hypoglycemic Agents; Obesity; Piperidines

Prandial glucose regulation has the potential for achieving good metabolic control with a low risk of hypoglycaemia and increased flexibility with regard to eating patterns. Comparative studies have suggested that the prandial glucose regulator repaglinide is at least equivalent to sulphonylureas in terms of efficacy, but incurs a lower risk of major hypoglycaemia. However, these trials employed fixed dosing and mealtime regimens, so repaglinide was not used as intended. This prospective investigation in a daily clinical setting aimed to assess the efficacy and tolerability profile of flexible prandial glucose regulation with repaglinide in Type 2 diabetes.. 5,985 patients with Type 2 diabetes in Germany were surveyed prospectively. These patients were assessed before and after a mean of 46 days treatment with repaglinide. At baseline, available data showed that 64% of patients had previously received therapy with conventional oral antidiabetic drugs, 22% were on diet alone, and 13% were naive to any treatment.. Overall, mean HbA1c decreased from 8.6 to 7.4%, fasting blood glucose from 183.9 to 134.2 mg/dl (10.2 to 7.4 mmol/l), blood glucose prior to main meals from 198.5 to 141.4 mg/dl (11 to 7.8 mmol/l), and blood glucose 2 hours after main meals from 219.3 mg/dl to 153.2 mg/dl (12.2 to 8.5 mmol/l). Subgroup analysis showed significant improvements in each of these parameters (P<0.0001) in therapy-naive patients, in patients switched from other oral antidiabetic drugs, and in patients receiving repaglinide as combination therapy. Body weight decreased slightly (1.2+/-2.7 kg). Only 49 hypoglycaemic episodes were reported, of which 38 cases were mild and no adverse sequelae to these events have been reported. Repaglinide also led to a liberating effect on lifestyle when patients were switched from other oral hypoglycaemic agents (OHAs), with 80% reporting a sense of relief at the prospect of being able to miss meals. The proportion of these patients reporting lifestyle restrictions as a result of fixed mealtimes declined from 36% to 7%. Before switching, 38% of the patients admitted to eating when not hungry for fear of hypoglycaemia, but only 10% continued this behaviour and patients took fewer supplementary snacks after switching to repaglinide.. Prandial glucose regulation with repaglinide improves metabolic control in patients with Type 2 diabetes without causing weight gain and with few hypoglycaemic episodes. This beneficial effect is seen in patients who are therapy-naive, have switched from alternative OHAs, or are in need of combination therapy. The prandial approach to treatment has a liberating effect with regard to eating behaviour that is welcomed by most patients switched from alternative therapies.

Topics: Attitude to Health; Blood Glucose; Carbamates; Cohort Studies; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Eating; Feeding Behavior; Female; Germany; Humans; Hypoglycemic Agents; Life Style; Male; Middle Aged; Piperidines; Professional Practice; Prospective Studies; Surveys and Questionnaires; Treatment Outcome; Weight Loss

Topics: Blood Glucose; C-Peptide; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Humans; Hypoglycemic Agents; Insulin; Piperidines

Pharmacokinetic profiles of single- and multiple-dose regimens of repaglinide were evaluated in 12 elderly subjects with type 2 diabetes. On day 1, following a 10-hour fast, subjects received a single 2-mg dose of repaglinide. Starting on day 2 and continuing for 7 days, each subject received a 2-mg dose of repaglinide 15 minutes before each of the three main meals. On day 9, subjects received a single 2-mg dose of repaglinide. Pharmacokinetic profiles, including area under the curve (AUC), log(AUC), maximal concentration (Cmax), log(Cmax), time to maximal concentration (Tmax), and half-life (T(1/2)), were determined at completion of the single- and multiple-dose regimens (days 1 and 9, respectively). Trough repaglinide values were collected on days 2 through 7. The mean log(AUC) values after multiple dosing were significantly higher than the values obtained after a single dose. The mean values for log(Cmax), and Tmax were comparable after each dosing regimen. The T(1/2) of repaglinide after multiple dosing was 1.7 hours. The trough values for repaglinide were low. No hypoglycemic events were reported. The pharmacokinetic profiles of repaglinide after single- and multiple-dose regimens were similar, and repaglinide was well tolerated by elderly subjects with type 2 diabetes.

Topics: Aged; Carbamates; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Male; Piperidines

1. Hypoglycaemia-inducing sulphonylureas, such as glibenclamide, inhibit cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels. In search of modulators of CFTR, we investigated the effects of the non-sulphonylurea hypoglycaemic agents meglitinide, repaglinide, and mitiglinide (KAD-1229) on CFTR Cl- channels in excised inside-out membrane patches from C127 cells expressing wild-type human CFTR. 2. When added to the intracellular solution, meglitinide and mitiglinide inhibited CFTR Cl- currents with half-maximal concentrations of 164+/-19 microM and 148+/-36 microM, respectively. However, repaglinide only weakly inhibited CFTR Cl- currents. 3. To understand better how non-sulphonylurea hypoglycaemic agents inhibit CFTR, we studied single channels. Channel blockade by both meglitinide and mitiglinide was characterized by flickery closures and a significant decrease in open probability (Po). In contrast, repaglinide was without effect on either channel gating or Po, but caused a small decrease in single-channel current amplitude. 4. Analysis of the dwell time distributions of single channels indicated that both meglitinide and mitiglinide greatly decreased the open time of CFTR. Mitiglinide-induced channel closures were about 3-fold longer than those of meglitinide. 5. Inhibition of CFTR by meglitinide and mitiglinide was voltage-dependent: at positive voltages channel blockade was relieved. 6. The data demonstrate that non-sulphonylurea hypoglycaemic agents inhibit CFTR. This indicates that these agents have a wider specificity of action than previously recognized. Like glibenclamide, non-sulphonylurea hypoglycaemic agents may inhibit CFTR by occluding the channel pore and preventing Cl- permeation.

Topics: Adenosine Triphosphate; Animals; Benzamides; Carbamates; Cell Line; Chloride Channels; Cyclic AMP-Dependent Protein Kinases; Cystic Fibrosis Transmembrane Conductance Regulator; Electric Conductivity; Epithelial Cells; Glyburide; Humans; Hypoglycemic Agents; Indoles; Ion Channel Gating; Isoindoles; Kinetics; Mice; Patch-Clamp Techniques; Piperidines; Sulfonylurea Compounds; Transfection

Nateglinide (NAT) stimulates insulin secretion from pancreatic beta-cells by closing K(ATP) channels. Because K(ATP) channels are widely distributed in cardiovascular (CV) tissues, we assessed the tissue specificity of NAT by examining its effect on K(ATP) channels in enzymatically isolated rat beta-cells, rat cardiac myocytes, and smooth muscle cells from porcine coronary artery and rat aorta with the patch-clamp method. The selectivity of known antidiabetic agents glyburide (GLY) and repaglinide (REP) was also studied for comparison. NAT was found to inhibit K(ATP) channels in the cells from porcine coronary artery and rat aorta with IC(50)s of 2.3 and 0. 3 mM, respectively, compared with 7.4 microM in rat beta-cells, indicating a respective 311- and 45-fold selectivity (p <.01) for beta-cells. With an IC(50) of 5.0 nM in beta-cells, REP displayed an approximately 16-fold (p <.05) selectivity for beta-cells over both types of vascular cells. GLY was nonselective between vascular and beta-cells. At equipotent concentrations (2x respective IC(50)s in beta-cells), NAT, GLY, and REP all caused 62% reduction of pancreatic K(ATP) current but a respective 39, 55, and 66% inhibition of cardiac K(ATP) current. These data collectively indicate that NAT, when compared with GLY and REP, at concentrations effective in stimulating insulin secretion is least likely to cause detrimental CV effects via blockade of CV K(ATP) channels.

Topics: Animals; Aorta, Thoracic; Carbamates; Cardiovascular System; Coronary Vessels; Cyclohexanes; Glyburide; Heart; Hypoglycemic Agents; Islets of Langerhans; Male; Muscle, Smooth, Vascular; Nateglinide; Phenylalanine; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Rats; Rats, Sprague-Dawley; Swine

The effects of the two prandial glucose regulators, repaglinide and nateglinide, on ATP-sensitive K(+) (K(ATP)) channel activity, membrane potential and exocytosis in single rat pancreatic A-cells were investigated using the patch-clamp technique. K(ATP) channel activity was reversibly blocked by repaglinide (K(d)=22 nM) and nateglinide (K(d)=410 nM) and this was associated with membrane depolarisation and initiation of electrical activity. The effect of repaglinide and nateglinide on stimulation of glucagon secretion by direct interference with the exocytotic machinery was investigated by the use of capacitance measurements. Nateglinide, but not repaglinide, at concentrations similar to those required to block K(ATP) channels potentiated Ca(2+)-evoked exocytosis 3-fold. In alphaTC1-9 glucagonoma cells addition of nateglinide, but not repaglinide, was associated with stimulation of glucagon secretion. These results indicate that the fast-acting insulin secretagogue nateglinide is glucagonotropic primarily by stimulating Ca(2+)-dependent exocytosis.

Topics: Animals; ATP-Binding Cassette Transporters; Calcium; Carbamates; Cyclohexanes; Eating; Electrophysiology; Exocytosis; Glucagon; Glucose; Hypoglycemic Agents; In Vitro Techniques; Islets of Langerhans; KATP Channels; Kinetics; Male; Nateglinide; Patch-Clamp Techniques; Phenylalanine; Piperidines; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Inwardly Rectifying; Rats; Rats, Inbred Lew; Stimulation, Chemical

Topics: Carbamates; Contraindications; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Piperidines

Recently, the number of agents to treat type 2 diabetes has increased markedly. In the past, the only agents practitioners had available to treat patients with type 2 diabetes mellitus were insulin and sulfonylureas. Today, three additional classes of agents with a total of six new drugs are available: acarbose, migital, repaglinide, metformin hydrochloride, troglitazone, and rosiglitazone. In the not-too-distant future, several other agents will be available for treating patients with diabetes. These new agents will allow physicians to control their diabetic patients' blood sugar levels without the need for insulin injections. This article reviews the new agents and provides practical suggestions regarding their use as monotherapy or in combination therapy.

Topics: Carbamates; Chromans; Diabetes Mellitus; Humans; Hypoglycemic Agents; Metformin; Piperidines; Sulfonylurea Compounds; Thiazoles; Thiazolidinediones; Troglitazone

Topics: Acarbose; Carbamates; Chromans; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Metformin; Piperidines; Thiazoles; Thiazolidinediones; Troglitazone

In type 2 diabetic patients, the important post-prandial hyperglycemic peak combined with the defective insulin secretion emphasizes the need for restoring a physiological insulin profile during meals, characterized by insulinemia peaking within 1 hour and returning to basal levels within 4 hours. During type 1 diabetes mellitus, short acting insulin analogs aim at counteracting on post-prandial hyperglycemic peak. During type 2 diabetes mellitus, repaglinide is the first fast-acting oral antidiabetic drug able to stimulate endogenous insulin secretion during meal by mimicking physiological insulin secretion pattern.

Topics: Carbamates; Diabetes Mellitus, Type 2; Humans; Hyperglycemia; Hypoglycemic Agents; Inulin; Piperidines

The natural history of type 2 diabetes involves a progressive pancreatic beta-cell dysfunction leading to quantitative, qualitative and/or temporal abnormalities in insulin secretion and insensitivity to insulin action which predominates in muscles. These abnormalities can be observed during early phases of glucose intolerance, but their determinism remains unclear. The high prevalence of type 2 diabetes, its increasing incidence among developed countries and the huge cost induced by diabetic complications explain why this disease is being viewed as a major public health issue. An earlier diagnosis by general practitioners and more intensive treatments are urged for patient and social beneficial outcome. In addition to non pharmacological (dietary, physical activity) approaches, several drugs were established as efficient therapies for type 2 diabetic patients: sulfonylureas acting by enhancing insulin secretion, metformin improving insulin resistance, or acarbose delaying carbohydrate intestinal absorption. These drugs have been used during the UKPDS trial; nevertheless, their effect was somehow limited, when considering long-term blood glucose control, risk for hypoglycemia, and/or prevention of macroangiopathy. The new generation of insulin secretion enhancers, including repaglinide, by allowing a reduction of total insulinemia, potentiating nutrient-induced insulin secretion, and minimizing risks for hypoglycemia, raises hope for a progress.

Topics: Carbamates; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diet, Diabetic; Exercise; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Piperidines

In addition to dietary and lifestyle changes, standing as the cornerstone of type 2 diabetes care, pharmacological treatments, whether as single or multidrug patterns, are often necessary for an efficient blood glucose control. Besides insulin, four different oral antidiabetic drug categories are available, each of them acting through different and potentially synergistic ways. Oral antidiabetic drugs include: 1) biguanides acting through the reduction of hepatic glucose production and are most efficient in obese patients; 2) alpha-glucosidase inhibitors delaying carbohydrate intestinal absorption; 3) thiazolidinediones or "glitazones", acting as insulin sensitizers; 4) insulin secretion enhancers, mainly including sulfonylureas, which increase insulin secretion and are being credited by a long clinical usage; these are now joined by the new generation of insulin secretion enhancers, led by repaglinide, which can mimic the physiological insulin secretion profile by a specific stimulatory effect on beta-cells characterized by its fast onset and short half-life. Obviously, the combination of these different antidiabetic drugs, by targetting different synergistic and additive pathways, can help to further improve blood glucose.

Topics: Carbamates; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Metformin; Piperidines

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin; Islets of Langerhans; Piperidines

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Exercise; Humans; Hyperglycemia; Hypoglycemic Agents; Piperidines; Weight Loss

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Homeostasis; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Piperidines

The action of repaglinide, a novel insulin secretagogue, was compared with the sulfonylurea glibenclamide with regard to the hypoglycemic action in vivo, binding to betaTC-3 cells, insulin secretion from perifused mouse islets, and capacity to stimulate exocytosis by direct interaction with the secretory machinery in single voltage-clamped mouse beta-cells. Two binding sites were identified: a high-affinity repaglinide (KD = 3.6 nmol/l) site having lower affinity for glibenclamide (14.4 nmol/l) and one high-affinity glibenclamide (25 nmol/l) site having lower affinity for repaglinide (550 nmol/l). In contrast to glibenclamide, repaglinide (in concentrations as high as 5 micromol/l) lacked the ability to enhance exocytosis in voltage-clamped beta-cells. Repaglinide was more potent than glibenclamide in stimulating insulin release from perifused mouse islets (EC50 29 vs. 80 nmol/l). The greater potency of repaglinide in vitro was paralleled by similar actions in vivo. The ED50 values for the hypoglycemic action were determined to be 10.4 and 15.6 microg/kg after intravenous and oral administration, respectively. The corresponding values for glibenclamide were 70.3 microg/kg (intravenous) and 203.2 microg/kg (oral). Further, repaglinide (1 mg/kg p.o.) was effective (P < 0.001) as an insulin-releasing agent in a rat model (low-dose streptozotocin) of type 2 diabetes. These observations suggest that the insulinotropic actions of repaglinide and glibenclamide in vitro and in vivo are secondary to their binding to the high-affinity repaglinide site and that the insulinotropic action of repaglinide involves both distinct and common cellular mechanisms.

Topics: Animals; Binding Sites; Binding, Competitive; Blood Glucose; Carbamates; Cohort Studies; Culture Techniques; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Evoked Potentials; Glucose; Glyburide; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Male; Mice; Mice, Inbred Strains; Osmolar Concentration; Patch-Clamp Techniques; Perfusion; Piperidines; Rats; Rats, Sprague-Dawley; Time Factors; Tritium

This study aims at gaining further insight into the mode of action of repaglinide in pancreatic islet B-cells. At a 1.0 mumol/L concentration, the meglitinide analog failed to affect the metabolism of exogenous D-glucose and that of endogenous nutrients in islets prelabeled with either L-[U-14C]glutamine or [U-14C]palmitate. Likewise, repaglinide (1.0 mumol/L) failed to modify significantly the incorporation of L-[4-3H]phenylalanine into TCA-precipitable material in islets exposed to a close-to-physiological concentration of D-glucose (7.0 mmol/L). The threshold concentration for the insulinotropic action of repaglinide was close to 0.1-1.0 mumol/L and a maximal response was reached at 10.0 mumol/L in islets incubated in the presence of 5.6-8.3 mmol/L D-glucose. At a higher hexose concentration (16.7 mmol/L), however, an enhancing action of repaglinide (10 mumol/L) upon glucose-stimulated insulin release was only observed over 25 min stimulation in perifused islets, no significant increase in insulin output being detected when islets were exposed to repaglinide (0.1 mumol/L to 0.1 mmol/L) over 90 min incubation at the high D-glucose level. The increase in insulin output evoked by repaglinide in the islets perifused at 16.7 mmol/L D-glucose coincided with a modest increase in 86Rb outflow and a marked stimulation of 45Ca efflux from prelabeled islets, suggesting stimulation of Ca2+ influx into the islet cells and subsequent activation of Ca(2+)-responsive K+ channels. When the administration of repaglinide was halted, the reversibility of its cationic and secretory effects was more pronounced in islets perifused at a high (16.7 mmol/L), rather than a low (6.0 mmol/L), D-glucose concentration. These findings support the view that the primary site of action of repaglinide consists in a remodeling of cationic fluxes, and document that this drug displays favorable attributes as an insulinotropic agent for the treatment of non-insulin-dependent diabetes, such as its lack of interference with nutrient metabolism and biosynthetic activity in isolated islets, the low threshold concentration for its insulin-releasing action and its capacity to augment, at least transiently, insulin release at a high concentration of D-glucose.

Topics: Animals; Calcium Radioisotopes; Carbamates; Cations; Female; Glucose; Glutamine; Hypoglycemic Agents; Insulin; Islets of Langerhans; Palmitic Acid; Piperidines; Rats; Rats, Wistar; Rubidium Radioisotopes

Topics: Carbamates; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Fasting; Humans; Hypoglycemic Agents; Piperidines; Postprandial Period

The influence of three daily oral doses of repaglinide (1.0 microg/g body wt.) on plasma insulin and glucose concentrations, pancreatic islet insulin content and both protein biosynthesis and insulin release in isolated islets incubated for 90 min in the presence of either 2.8 or 16.7 mM D-glucose was examined in both control and hereditary diabetic Goto-Kakizaki (GK) rats. In the control rats, repaglinide lowered the plasma glucose concentration, whilst failing to affect significantly the plasma insulin concentration or insulin/glucose ratio, 24 h after the last administration of the antidiabetic agent. Despite a severe decrease of islet insulin content, the ratio between insulin release and content was not altered in islets obtained from repaglinide-treated control rats and incubated in the presence of 16.7 mM D-glucose. Also the biosynthesis of islet peptides was increased at both low and high hexose concentrations. In GK rats, repaglinide administration affected neither plasma glucose nor insulin concentration, restored a normal value for the otherwise abnormally high basal insulin output, increased the 16.7 mM/2.8 mM ratio for insulin release, and again augmented protein biosynthesis at both low and high hexose concentrations. In both control and GK rats, the stress induced by bleeding and decapitation augmented plasma glucose concentration. This effect was more pronounced in GK than in control rats and, in the diabetic animals, coincided with a severe lowering of the plasma insulin/glucose ratio, suggesting a higher adrenergic sensitivity of islet cells in the GK than in control rats. The increased secretory responsiveness to glucose and increased biosynthetic activity found in islets from GK rats after repaglinide administration, are considered favourable attributes of this meglitinide analogue in the perspective of its use as an insulinotropic agent in noninsulin-dependent diabetes.

Topics: Administration, Oral; Animals; Blood Glucose; Carbamates; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Female; Glucose; Hypoglycemic Agents; Insulin; Islets of Langerhans; Piperidines; Rats; Rats, Wistar

Topics: Aged; Carbamates; Diabetes Mellitus, Type 2; Drug Interactions; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Piperidines

Topics: Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Piperidines

This study investigates the insulin secretory responsiveness of pancreatic islets to repaglinide in an experimental model of B-cell glucose incompetence. Rats were infused for 2 d with a 1.67 M solution of D-glucose administered at a rate close to 2.8 mL/h. This resulted in a modest rise in glycemia, a severe increase in plasma insulin concentration, an increased sensitivity of B-cells to adrenergic stress, an abnormally high insulin output from isolated islets perifused in the presence of 16.7 mM D-glucose, and a paradoxical transient increase in insulin release from the islets in response to a fall in hexose concentration. The early increment in insulin output evoked by repaglinide, in the presence of 16.7 mM D-glucose, was not lower in the islets from glucose-infused rats than in those from control rats. Moreover, when the meglitinide analog was administered concomitantly with the removal of D-glucose from the perifusion medium, the early response to repaglinide was further increased. Even after 24 min of glucose deprivation, the output of insulin by the islets from glucose-infused rats was higher in the presence of repaglinide than in its absence. These findings indicate that, in this model of B-cell dysfunction, the secretory responsiveness to repaglinide, as distinct from that to glucose, is fully preserved. Therefore, when taken into consideration together with prior observations, these findings argue in support of the use of this insulinotropic agent in the treatment of noninsulin-dependent diabetes.

Topics: Animals; Benzamides; Blood Glucose; Carbamates; Female; Glucose Solution, Hypertonic; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Piperidines; Rats; Rats, Wistar; Stereoisomerism

The structure-activity relationships in two series of hypoglycemic benzoic acid derivatives (5, 6) were investigated. Series 5 resulted from meglitinide (3) when the 2-methoxy was replaced by an alkyleneimino residue. Maximum activity was observed with the cis-3, 5-dimethyl-piperidino (5h) and the octamethyleneimino (5l) residues. Series 6 resulted from the meglitinide analogon 4 bearing an inversed amido function when the 2-methoxy, the 5-fluoro, and the alpha-methyl residue were replaced by a 2-piperidino, a 5-hydrogen, and a larger alpha-alkyl residue, respectively. An alkoxy residue ortho to the carboxy group further increased activity and duration of action in the rat. The most active racemic compound, 6al (R4 = isobutyl; R = ethoxy), turned out to be 12 times more active than the sulfonylurea (SU) glibenclamide (1). Activity was found to reside predominantly in the (S)-enantiomers. Compared with the SUs 1 and 2 (glimepiride), the most active enantiomer, (S)-6al (AG-EE 623 ZW; repaglinide; ED50 = 10 micro/kg po), is 25 and 18 times more active. Repaglinide turned out to be a useful therapeutic for type 2 diabetic patients; approval was granted recently by the FDA and the EMEA. From investigations on the pharmacophoric groups in compounds of type 5 and 6, it was concluded that in addition to the two already known-the acidic group (COOH; SO2NH) and the amidic spacer (CONH; NHCO)-the ortho residue R1 (alkyleneimino; alkoxy; oxo) must be regarded as a third one. A general pharmacophore model suitable for hypoglycemic benzoic acid derivatives, SUs, and sulfonamides is proposed (Figure 6). Furthermore, from superpositions of low-energy conformations (LECs) of 1, 2, and (S)-6al, it was concluded that a common binding conformation (LEC II; Figure 10B) may exist and that differences in binding to the SU receptor and in the mechanism of insulin release between repaglinide and the two SUs may be due to specific hydrophobic differences.

Topics: Administration, Oral; Animals; ATP-Binding Cassette Transporters; Benzoates; Blood Glucose; Carbamates; Crystallography, X-Ray; Female; Glyburide; Hypoglycemic Agents; Models, Molecular; Molecular Conformation; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Rats; Rats, Wistar; Receptors, Drug; Stereoisomerism; Structure-Activity Relationship; Sulfonylurea Compounds; Sulfonylurea Receptors

Topics: Administration, Oral; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Diet, Diabetic; Glucose; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Piperidines

1. Repaglinide, a novel compound with a nonsulphonylurea structure, is currently being clinically tested as a therapeutic agent. In the present study, the hypoglycaemic effects of repaglinide in rats and dogs were investigated. 2. Whereas the R-enantiomer, AG-EE 624 ZW, showed only weak hypoglycaemic activity, the S-enantiomer, repaglinide, turned out to be a potent hypoglycaemic compound in rats after oral as well as after intravenous administration. Only 50% of the dose of repaglinide was needed to be equieffective with the racemic mixture AG-EE 388 ZW. The corresponding ED50 values calculated for the effects after 120 min p.a. (intravenous administration) were 3.4 micrograms kg-1 (repaglinide) and 6 micrograms kg-1 (AG-EE 388 ZW). 3. When compared to glimepiride or glibenclamide, repaglinide displayed a 18 to 25 times higher potency in fasted rats. The ED50 values calculated for the effects after 120 min p.a. (oral administration) were 10 micrograms kg-1 (repaglinide), 182 micrograms kg-1 (glimepiride) and 255 micrograms kg-1 (glibenclamide). 4. In glucose loaded rats (0.5, 1.0, 2.0 and 3.0 g kg-1 glucose, p.o.) repaglinide exerted a very strong antihyperglycaemic activity which was even more pronounced than under normoglycaemic conditions. So for a reduction in blood glucose of 1 mmol l-1, 10.3, 9.3, 7.0 8.4 and 7.2 micrograms kg-1 repaglinide were needed after glucose loads of 0.0, 0.5, 1.0, 2.0 and 3.0 g kg-1, respectively. 5. In beagle dogs repaglinide again showed a pronounced hypoglycaemic effect (ED50 28.3 micrograms kg-1) which lasted for up to 24 h. However, insulin levels were only transiently increased. 6. The in vivo data presented are well supported by recently published in vitro findings. From its activity profile, repaglinide appears to be a promising new therapeutic agent.

Topics: Animals; Carbamates; Dogs; Female; Glyburide; Hypoglycemic Agents; Piperidines; Rats; Rats, Wistar; Stereoisomerism; Sulfonylurea Compounds

Repaglinide (1 microg/g body wt), glibenclamide (10 microg/g) or glimepiride (10 microg/g) were administered orally to either fed or overnight fasted normal rats and hereditarily diabetic animals (GK rats). In both fed and starved normal rats, repaglinide provoked a greater and more rapid increase in plasma insulin concentration and an earlier fall in glycemia than those observed after administration of the hypoglycemic sulfonylureas. Likewise, in fed GK rats, the plasma insulin concentration was already increased by 30.0 +/- 1.6% 15 min after administration of repaglinide, whilst a sizeable insulinotropic action of the sulfonylureas was only recorded at much later times. Except for a lower glycemia at the 240th min of the test, there was little to distinguish, in starved GK rats, between control experiments including the oral administration of the solution of carboxymethylcellulose used as vehicle and the experiments conducted with the antidiabetic agents. Several converging observations indicated that glimepiride stimulated insulin release more promptly than glibenclamide. It is proposed that advantage can be taken from these vastly different time-courses of the hormonal and metabolic response to distinct hypoglycemic agents to optimize the control of glucose homeostasis in non-insulin-dependent diabetic subjects.

Topics: Administration, Oral; Animals; Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Fasting; Female; Glyburide; Hypoglycemic Agents; Insulin; Male; Piperidines; Rats; Rats, Wistar; Sulfonylurea Compounds

A novel ester of succinic acid (1,2,3-tri(methylsuccinyl)glycerol ester; 3SMG) was found to stimulate insulin release and to potentiate the insulinotropic action of gliquidone and repaglinide when administered intravenously to normal anaesthetized rats in a dose as low as 0.07 mumol g-1 body wt. The ester failed, however, to augment plasma insulin concentration when given enterally. The design of succinic acid esters of high insulinotropic potential might thus allow efficient stimulation of insulin secretion in non-insulin-dependent diabetes, without requiring unpractical high dosage and without running the risk of an undesirable increase in gluconeogenesis.

Topics: Animals; Blood Glucose; Carbamates; Drug Synergism; Esters; Hypoglycemic Agents; Insulin; Male; Piperidines; Rats; Rats, Wistar; Stereoisomerism; Succinates; Sulfonylurea Compounds

The hypoglycemic agents, glibenclamide and repaglinide, when administered intragastrically to overnight fasted hereditarily diabetic animals, were found to oppose the rise in the plasma insulin/glucose ratio otherwise evoked by refeeding of the GK rats. Such was not the case after oral administration of glimepiride, despite the fact that this sulfonylurea minimized the rise in glycemia associated with refeeding. The altered restoration of a high insulin/glucose ratio in GK rats that received glibenclamide or repaglinide before refeeding suggests that these long-acting hypoglycemic agents may delay the refeeding-induced relief of the B-cell from the fasting-associated refractoriness to glucose.

Topics: Animals; Blood Glucose; Carbamates; Diabetes Mellitus, Experimental; Food; Glyburide; Hypoglycemic Agents; Insulin; Male; Piperidines; Rats; Starvation

Several meglitinide analogs are currently under investigation as potential insulinotropic tools for the treatment of noninsulin-dependent diabetes. The present study aimed to further insight into the effect of these agents on the secretion of insulin, glucagon, and somatostatin by the isolated perfused pancreas. Both repaglinide (0.01 microM) and A-4166 (1.0 microM) stimulated insulin and somatostatin release, but failed to affect glucagon output, from pancreases exposed to 5.6 mM D-glucose. The secretory response of the B- and D-cells to the hypoglycemic agents was much less marked than that caused by a rise in hexose concentration from 5.6-16.7 mM. Although repaglinide was tested at a concentration a hundred times lower than that of A-4166, the drug-induced increase in both insulin and somatostatin secretion persisted for a longer time after exposure to repaglinide, than to A-4166. The relevance of these findings to the use of meglitinide analogs as antidiabetic agents is double. First, they document that these drugs, although enhancing both insulin and somatostatin release, do not provoke an undesirable stimulation of glucagon secretion. Second, they indicate that even at a very low concentration, repaglinide provokes a protracted insulinotropic action, thus suggesting that the reversibility of the secretory response to this or other meglitinide analogs represents an intrinsic molecular attribute, unrelated to either their biological potency or the relative extent of B-cell stimulation.

Topics: Animals; Benzamides; Blood Glucose; Carbamates; Cyclohexanes; Female; Glucagon; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Nateglinide; Perfusion; Phenylalanine; Piperidines; Rats; Rats, Wistar; Somatostatin

Topics: Blood Glucose; Carbamates; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin Resistance; Piperidines

The insulinotropic action of the meglitinide analogues KAD-1229, A-4166 and repaglinide was examined in rat pancreatic islets deprived of exogenous nutrient or incubated in the presence of nutrient secretagogues such as D-glucose and the methyl esters of pyruvic acid, succinic acid and glutamic acid. The meglitinide analogues exerted little effect on insulin release in the absence of exogenous nutrient or in the presence of methyl pyruvate. They caused obvious stimulation of insulin output in the presence of D-glucose, dimethyl succinate or dimethyl glutamate. It is proposed, therefore, that suitable esters of dicarboxylic nutrients could be used to potentiate the secretory response to meglitinide analogues in non-insulin-dependent diabetes mellitus.

Topics: Animals; Carbamates; Cells, Cultured; Cyclohexanes; Glucose; Glutamates; Hypoglycemic Agents; Indoles; Insulin; Insulin Secretion; Islets of Langerhans; Isoindoles; Nateglinide; Phenylalanine; Piperidines; Pyruvates; Rats; Succinates

The present study demonstrates the action of the hypoglycaemic drugs repaglinide and glibenclamide in cultured newborn rat islet cells and mouse beta TC3 cells. In cell-attached membrane patches of newborn rat islet cells repaglinide (10 nmol/l) and glibenclamide (20 nmol/l) decrease the open probability of single ATP-sensitive K(+)-channels to approximately 10% of the activity prior to addition of the drugs in short-term experiments (< 5 min). The influence of repaglinide and glibenclamide on the ATP-sensitive K+ current was studied using the whole-cell patch clamp configuration. A half-maximal steady-state inhibition of the ATP-sensitive K+ currents is observed at 89 pmol/l repaglinide and at 47 pmol/l glibenclamide in whole-cell experiments of longer duration (30 min). Applying digital Ca2+ imaging on single beta TC3 cells we found that repaglinide and glibenclamide induced a concentration-dependent increase in intracellular free Ca2+ concentration ([Ca2+]i) with a half-maximal effect at 0.5 nmol/l for both drugs in long-term experiments (30 min). The rise in [Ca2+]i results from Ca2+ entry through voltage-dependent L-type Ca(2+)-channels since it is inhibited by verapamil (10 mumol/l). The effect of repaglinide and glibenclamide is partly reversible (approximately 80%).

Topics: Adenosine Triphosphate; Animals; Animals, Newborn; Calcium; Carbamates; Cell Line; Cells, Cultured; Cytosol; Dose-Response Relationship, Drug; Glyburide; Hypoglycemic Agents; Ion Channel Gating; Islets of Langerhans; Kinetics; Membrane Potentials; Mice; Patch-Clamp Techniques; Piperidines; Potassium Channels; Rats; Serum Albumin; Time Factors; Verapamil

Non-sulfonylurea hypoglycemic agents of the meglitinide family such as S3075, repaglinide, KAD-1229, and A-4166, were found to display a comparable U-shaped conformation by molecular modelling, with hydrophobic cycles placed at the extremity of each branch and a peptidic bond placed at the bottom of the U. A comparable conformation was observed with the hypoglycemic sulfonylureas glibenclamide and glimepiride. A different conformation with a greater distance between the hydrophobic cycles at the extremity of each branch was found, however, with the biologically inactive enantiomers of A-4166 and repaglinide and the poorly efficient insulinotropic agent meglitinide. The identification of a common conformation of these hypoglycemic agents may help in the design of highly active compounds and provide an imprint of their postulated target receptor on the pancreatic B-cell plasma membrane.

Topics: Benzamides; Carbamates; Cyclohexanes; Drug Design; Glyburide; Hypoglycemic Agents; Indoles; Isoindoles; Molecular Conformation; Nateglinide; Phenylalanine; Piperidines; Stereoisomerism; Structure-Activity Relationship; Sulfonylurea Compounds

At normal extracellular K+ concentration (5 mM), the meglitinide analogues A-4166, KAD-1229, repaglinide and S3075, all tested at a 10 mu M concentration, markedly enhanced insulin release evoked by 6 mM D-glucose in isolated rat pancreatic islets. They failed, however, to augment the much higher rate of insulin release evoked by D-glucose in islets exposed to a high K+ concentration (30 mM). Under the latter conditions, the potent diazoxide analogue BPDZ-44 (50 mu M) did not exert any sizeable effect upon insulin release. Even at normal K+ concentration, BPDZ-44 (50 mu M), which suppressed glucose-stimulated insulin release, only caused a partial inhibition of the insulinotropic action of A-4166 and failed to affect significantly insulin secretion in the presence of KAD-1229, repaglinide or S3075. These findings argue against the view that meglitinide analogues could affect cytosolic Ca2+ activity independently of the closing of ATP-sensitive K+ channels. The present results also indicate that, with the possible exception of A-4166 which in the least potent secretagogue in this series, meglitinide analogues are able, like hypoglycemic sulphonylureas, to fully protect ATP-sensitive K+ channels against their activation by BPDZ-44.

Topics: Animals; Benzamides; Carbamates; Cyclohexanes; Female; Hypoglycemic Agents; Indoles; Insulin; Insulin Secretion; Islets of Langerhans; Isoindoles; Nateglinide; Phenylalanine; Piperidines; Potassium; Rats

The sodium and calcium ionophoretic activity of meglitinide and three of its hypoglycemic analogs, namely S3075, KAD-1229 and repaglinide was examined in an artificial membrane model. All agents were able to cause the translocation of 45Ca and 22Na from an aqueous solution into an immiscible organic phase. The results were compatible with the formation of a calcium-ionophore complex with a 1-2 stoichiometry. The ionophoretic activity ranged in the following hierarchy: KAD-1229 > S3075 > repaglinide = meglitinide and, hence, did not closely parallel the insulinotropic potential of these non-sulfonylurea hypoglycemic agents. It is proposed, therefore, that the ionophoretic capacity of meglitinide analogs may not represent an essential determinant of their insulin-releasing action.

Topics: Benzamides; Biological Transport; Calcium; Carbamates; Hypoglycemic Agents; Indoles; Insulin; Insulin Secretion; Ionophores; Isoindoles; Membranes, Artificial; Models, Biological; Piperidines; Sodium; Structure-Activity Relationship

The insulinotropic action of meglitinide was compared to that of its analogs S 3075, A-4166, KAD-1229 and repaglinide. None of these hypoglycemic agents significantly enhanced insulin output from rat pancreatic islets incubated for 90 min in the absence of exogenous nutrient. However, all these agents, when tested at a 10 microM concentration, augmented insulin release evoked by either 7 mM D-glucose or 10 microM succinic acid monomethyl ester (SAM). In this respect, meglitinide was a less efficient secretagogue than the other non-sulfonylurea hypoglycemic agents. Moreover, in the presence of 7 mM D-glucose, the lowest concentration of the drug required to cause a significant increase in insulin output decreased from about 1.0 microM for meglitinide to 0.1 microM with A-4166, KAD-1229 or repaglinide and even close to 10 nM in the case of S 3075. The concentration-response relationship thus yielded the following hierarchy, S 3075 > KAD-1229 = repaglinide > A-4166 > meglitinide, there being a difference of more than two orders of magnitude between the weakest and most potent agent.

Topics: Animals; Benzamides; Carbamates; Cyclohexanes; Female; Glucose; Hypoglycemic Agents; In Vitro Techniques; Indoles; Insulin; Insulin Secretion; Islets of Langerhans; Isoindoles; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Rats; Structure-Activity Relationship; Succinates

A sensitive and selective high-performance liquid chromatographic assay has been developed for a new hypoglycaemic agent AG-EE 388 ZW (I) in human plasma. Plasma samples containing I were acidified with 0.2 M hydrochloric acid, directly injected into C2 reversed-phase pre-columns, and cleaned up on-line. After pre-column switching, the substance was separated isocratically in 15 min on a C18 reversed-phase column. Quantitation was performed after amperometric detection by external standard calibration curves. The linearity of the assay was demonstrated over the therapeutic concentration range 5-200 ng/ml. between-day coefficient of variation was 9.2% at 30 ng/ml. The limit of detection was 5 ng/ml in plasma. Determination of human plasma samples after intravenous and oral administration of 1 mg of 14C-labelled I demonstrated the applicability of the assay for pharmacokinetic studies in humans.

Topics: Administration, Oral; Carbamates; Chromatography, High Pressure Liquid; Electrochemistry; Humans; Hypoglycemic Agents; Injections, Intravenous; Piperidines