morphine-3-glucuronide and morphine-6-glucuronide

The main aim of synthesizing permanently charged opioids is to ensure that they do not enter the central nervous system. Such drugs can provide analgesic activity with reduced sedation and other side effects on the central nervous system.. We undertook a search of bibliographic databases for peer-reviewed research literature and also summarized our published results in this field.. The present review focuses on the characterization of permanently charged opioids by various physicochemical methods, and in vitro as well as in vivo tests. The basicity and lipophilicity of opioid alkaloids are discussed at the microscopic, speciesspecific level. Glucuronide conjugates of opioids are also reviewed. Whereas the primary metabolite morphine-3-glucuronide does not bind to opioid receptors with high affinity, morphine-6-glucuronide is a potent analgesic, at least, partly due to its unexpectedly high lipophilicity. We discuss the quaternary ammonium opioid derivatives of a permanent positive charge, detailing their antinociceptive activity and effects on gastrointestinal motility in various in vivo animal tests and in vitro studies. Compounds with antagonistic activity are also reviewed. The last part of our study concentrates on sulfate conjugates of morphine derivatives that display unique pharmacological properties because they carry a negative charge at any pH value in the human body.. In conclusion, the findings of this review confirm the importance of permanently charged opioids in the investigated fields of pharmacology.

Topics: Analgesics, Opioid; Animals; Drug Discovery; Gastrointestinal Motility; Humans; Morphine Derivatives; Pain; Quaternary Ammonium Compounds; Receptors, Opioid; Sulfates

Morphine-6-glucuronide (M6G) is a strong µ-receptor agonist with higher affinity than morphine itself. It has been suggested that M6G contributes to the analgesic effect after administration of morphine, but the extent of its contribution remains unclear.. In order to elucidate the relative contribution of both drugs to the overall analgesic effect mediated by the µ-receptor, published data on µ-receptor binding, plasma protein binding, concentrations [preferably area under the concentration-time curve (AUC)] of morphine and M6G in blood or cerebrospinal fluid (CSF), or concentration ratios were used to calculate free CSF concentration corrected for receptor binding for each compound. To compare different routes of administration, free CSF concentrations of M and M6G corrected for potency were added and compared with oral administration.. Based on AUC data, there is a major contribution of M6G to the overall analgesic effect; the mean contributions being estimated as 96.6%, 85.6%, 85.4%, and 91.3% after oral, s.c., i.v., and rectal administration of morphine, respectively. In patients with renal insufficiency, 97.6% of the analgesic effect is caused by M6G when morphine is given orally. Owing to accumulation of M6G over time in these patients, morphine may be regarded as a prodrug.. When administering morphine to patients, the analgesic effect is mainly caused by M6G instead of morphine itself, irrespective of the route of administration. Therefore, the patient's kidney function plays a key role in determining the optimal daily dose of morphine.

Topics: Administration, Oral; Administration, Rectal; Analgesics, Opioid; Humans; Injections, Intravenous; Injections, Subcutaneous; Morphine; Morphine Derivatives

The chemical structures of morphine and its metabolites are closely related to the clinical effects of drugs (analgesia and side-effects) and to their capability to cross the Blood Brain Barrier (BBB). Morphine-6-glucuronide (M6G) and Morphine-3-glucuronide (M3G) are both highly hydrophilic, but only M6G can penetrate the BBB; accordingly, M6G is considered a more attractive analgesic than the parent drug and the M3G. Several hypotheses have been made to explain these differences. In this review we will discuss recent advances in the field, considering brain disposition of M6G, UDP-glucoronosyltransferases (UGT) involved in morphine metabolism, UGT interindividual variability and transport proteins.

Topics: Analgesics, Opioid; Animals; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Blood-Brain Barrier; Brain; Glucuronosyltransferase; Humans; Liver; Mice; Morphine; Morphine Derivatives; Neoplasms; Pain; Rats; Receptors, Opioid, mu

This article reviews the pharmacokinetics of heroin after intravenous, oral, intranasal, intramuscular and rectal application and after inhalation in humans, with a special focus on heroin maintenance therapy in heroin dependent patients. In heroin maintenance therapy high doses pharmaceutically prepared heroin (up to 1000 mg/day) are prescribed to chronic heroin dependents, who do not respond to conventional interventions such as methadone maintenance treatment. Possible drug-drug interactions with the hydrolysis of heroin into 6-monoacetylmorphine and morphine, the glucuronidation of morphine and interactions with drug transporting proteins are described. Since renal and hepatic impairment is common in the special population of heroin dependent patients, specific attention was paid on the impact of renal and hepatic impairment. Hepatic impairment did not seem to have a clinically relevant effect on the pharmacokinetics of heroin and its metabolites. However, some modest effects of renal impairment have been noted, and therefore control of the creatinine clearance during heroin-assisted treatment seems recommendable.

Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Drug Interactions; Heroin; Humans; Kidney Diseases; Liver Diseases; Morphine; Morphine Derivatives

Morphine metabolites are involved in various ways in determining the complex effects of morphine, both favourable and adverse, and may complicate the clinical use of morphine in the treatment of cancer pain. The production and effects of the principal morphine metabolites, morphine-3-glucuronide and morphine-6-glucuronide, in both normal and pathological states have been reviewed in the current literature. Therapeutic implications are also reviewed on the basis of experimental and clinical reports. The presence of these metabolites should be recognized in the chronic treatment of cancer pain with morphine, especially in the presence of renal impairment, and should be considered to have an important influence on opioid responsiveness, defined as a balance between the achievement of an optimal analgesia and the occurrence of adverse effects.

Topics: Analgesics, Opioid; Humans; Morphine; Morphine Derivatives; Neoplasms; Pain

In a systematic review of 57 studies with information on 1232 patients we examined the effect of age, renal impairment, route of administration, and method of analysis on the ratios of morphine-3-glucuronide:morphine (M3G:M) and morphine-6-glucuronide:morphine (M6G:M) and the relative concentrations of M3G and M6G. Across all studies the range of the ratios of metabolites to morphine was wide (0.001-504 for M3G:M, and 0-97 for M6G:M). Neonates produced morphine glucuronides at a lower rate than older children or adults. Metabolite ratios were higher in renal impairment. Routes of administration which avoided first pass metabolism (intravenous, transdermal, rectal, intramuscular, epidural and intrathecal) resulted in lower metabolite production than oral, buccal or sublingual. Metabolite production was similar for single and multiple dosing. There was no evidence of differences between methods of assay. There was a high correlation between the two glucuronide metabolites in spite of the different situations studied, supporting a single glucuronidating enzyme. Morphine was present in CSF at a fourfold higher concentration than the glucuronide metabolites.

Topics: Adult; Aging; Analgesics, Opioid; Child; Dose-Response Relationship, Drug; Drug Administration Routes; Humans; Infant, Newborn; Kidney Diseases; Morphine; Morphine Derivatives

Morphine is a potent opioid analgesic widely used for the treatment of acute pain and for long-term treatment of severe pain. Morphine is a member of the morphinan-framed alkaloids, which are present in the poppy plant. The drug is soluble in water, but its solubility in lipids is poor. In man, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) are the major metabolites of morphine. The metabolism of morphine occurs not only in the liver, but may also take place in the brain and the kidneys. The glucuronides are mainly eliminated via bile and urine. Glucuronides as a rule are considered as highly polar metabolites unable to cross the blood-brain barrier. Although morphine glucuronidation has been demonstrated in human brain tissue, the capacity is very low compared to that of the liver, indicating that the M3G and M6G concentrations observed in the cerebrospinal fluid (CSF) after systemic administration reflect hepatic metabolism of morphine and that the morphine glucuronides, despite their high polarity, can penetrate into the brain. Like morphine, M6G has been shown to be relatively more selective for mu-receptors than for delta- and kappa-receptors while M3G does not appear to compete for opioid receptor binding. The analgesic properties of M6G were recognised in the early 1970s and more recent work suggests that M6G might significantly contribute to the opioid analgesia after administration of morphine. The analgesic potency of M6G after intracerebroventricular (ICV) or intrathecal (IT) administration in rats is from 45-800 timer greater than that of morphine, depending on the animal species and the experimental antinociceptive test used. Furthermore, the development of a sensitive high-performance liquid chromatography (HPLC) assay for the quantitative determination of morphine, M6G and M3G has revealed that M6G and M3G were present in abundance after chronic oral morphine administration and that the area under the plasma concentration-time curve exceeded that of morphine. M3G has been found to antagonise morphine and M6G induced analgesia and ventilatory depression in the rat, which has led to the hypothesis that M3G may influence the development of morphine tolerance. M3G exhibits no analgesic effect after ICV or IT administration. Some studies do, however, indicate that M3G may cause non-opioid mediated hyperalgesia/allodynia and convulsions after IT administration in rats. These observations led to the hypothesis that M3G might be resp

Topics: Analgesics, Opioid; Animals; Humans; Morphine; Morphine Derivatives; Receptors, Opioid

Topics: Animals; Biotransformation; Humans; Morphine; Morphine Derivatives; Narcotics

Topics: Animals; Half-Life; Humans; Morphine; Morphine Derivatives; Rats; Renal Insufficiency

Topics: Animals; Binding Sites; Drug Design; Humans; Minoxidil; Morphine Derivatives; Receptors, Opioid

Currently, the majority of the surgical procedures performed in paediatric hospitals are done on a day care basis, with post-operative pain being managed by caregivers at home. Pain after discharge of these post-operative children has historically been managed with oral codeine in combination with paracetamol (acetaminophen). Codeine is an opioid, which elicits its analgesic effects via metabolism to morphine and codeine-6-glucuronide. Oral morphine is a feasible alternative for outpatient analgesia; however, the pharmacokinetics of morphine after oral administration have been previously described only sparsely, and there is little information in healthy children.. The clinical trial included 40 children from 2 to 6 years of age, with an American Society of Anaesthesiologists physical status classification of 1 or 2, who were undergoing surgical procedures requiring opioid analgesia. Morphine was orally administered prior to surgery in one of three doses: 0.1 mg/kg, 0.2 mg/kg and 0.3 mg/kg. Blood samples were collected for plasma morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) concentrations at 30, 60, 90, 120, 180 and 240 min after administration. All analyses were performed with the non-linear mixed-effect modelling software NONMEM version 7.2, using the first-order conditional estimation (FOCE) method.. A pharmacokinetic model was developed to simultaneously describe the plasma profiles of morphine and its metabolites M3G and M6G after a single dose of oral morphine in young children (2-6 years of age). The disposition of morphine, M3G and M6G in plasma was best described by a one-compartment model. M3G and M6G metabolite formation was best described by a delay transit compartment, indicating a delay in the appearance of these two major metabolites.. This model provides a foundation on which to further evaluate the use of oral morphine and its safety in young children. Longer follow-up time for morphine oral doses and incorporation of other important covariates, such as phenotype, will add value and will help overcome the limitations of the presented population pharmacokinetic analysis.

Topics: Administration, Oral; Analgesics, Opioid; Child; Child, Preschool; Codeine; Cytochrome P-450 CYP2D6; Female; Humans; Male; Models, Biological; Morphine; Morphine Derivatives; Pain, Postoperative; Polymorphism, Genetic; Tertiary Care Centers

Codeine is an analgesic drug acting on μ-opioid receptors predominantly via its metabolite morphine formed almost exclusively by CYP2D6. Genetic polymorphisms in CYP2D6 are associated with diminished pain relief and/or severe opioid side effects. In Chinese individuals, CYP2D6*10 is the most common allele with reduced enzyme activity. In this study, we investigated the effect of this allele on the pharmacokinetics of codeine and its metabolites.. A blood sample was collected from healthy Mongolian volunteers for CYP2D6 genotyping using a PCR-RFLP assay. A pharmacokinetic study was then carried out in three groups with CYP2D6*1/*1 (n=10), CYP2D6*1/*10 (n=10) and CYP2D6*10/*10 (n=9) genotypes by collecting serial blood samples for determination of plasma levels of codeine and its metabolites, morphine, morphine 3-glucuronide (M3G) and morphine 6-glucuronide (M6G) before and after a single 30-mg oral dose of codeine phosphate. Codeine and its metabolites were measured by LC-MS/MS.. No significant differences were observed in the pharmacokinetic parameters of codeine in the three genotype groups. However, the C( max) and AUC(0-∞) of morphine, M3G and M6G were significantly different between the study groups (P<0.05). Compared with the *1/*1 group, the AUC(0-∞) for morphine in the *1/*10 and *10/*10 groups decreased by ratios (95 % CI) of 0.93 (0.26-1.59) and 0.494 (0.135-0.853) respectively. Corresponding ratios for M3G were 0.791 (0.294-1.288) and 0.615 (0.412-0.818) and for M6G were 0.643 (0.39-0.957) and 0.423 (0.267-0.579).. This study demonstrates that the CYP2D6*10 allele plays an important role in the pharmacokinetics of the O-demethylated metabolites of codeine after oral administration.

Topics: Administration, Oral; Adult; Alleles; Analgesics, Opioid; Area Under Curve; Asian People; Codeine; Cytochrome P-450 CYP2D6; Female; Genotype; Humans; Male; Mongolia; Morphine; Morphine Derivatives; Polymorphism, Genetic; Young Adult

Pain is one of the most prevalent and distressing symptoms in patients with cancer. There is evidence from observational studies that many patients do not get adequate relief. Although data in the literature confirm the effectiveness of most opioid drugs for the treatment of chronic pain, there is limited information about opioid titration.. The aim of this study was to evaluate the clinical pharmacokinetics of morphine (M) and their correlation with pharmacodynamic results (effective daily dose of M and side effects) during the M titration phase, in the management of chronic cancer pain. Fifty-two consecutive patients were administered Oramorph (Molteni Farmaceutici, Scandicci, Florence, Italy; beginning with 5 mg every 6 hours), to maintain pain intensity at low levels (visual analog scale <4). M, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) plasma concentrations were determined by a mass spectrometric assay.. Expected pharmacokinetic parameters were based on a pharmacokinetic profile extrapolated from 39 patients: M total clearance varied between 1.5 and 6.42 L·h(-1)·kg(-1); the median apparent volume of M distribution was 25.0 L/kg, and the elimination half-life was 4.4 hours. Over the entire period of treatment, a weak correlation between M and M3G or M6G concentrations was found, but the metabolite ratio (M3G/M6G) remained quite stable for each patient and at different sampling times. At the end of titration, the M6G/M ratio was significantly higher in the patients whose effective M concentration was below the median (5.2 ng/mL), than in patients in whom the concentration was above the median (M6G/M: 13.0 and 9.0, respectively).. This article presents the pharmacokinetic profiles of M and its metabolites: their concentration ratio could help clinicians to optimize individual therapies and tailor the dose to individual needs. Our results indicate that the relationship between M6G and M could represent a potentially useful parameter to personalize M dosing.

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Analgesics, Opioid; Body Mass Index; Chromatography, High Pressure Liquid; Chronic Pain; Drug Monitoring; Female; Half-Life; Humans; Male; Metabolic Clearance Rate; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain Measurement; Polymorphism, Genetic; Sex Factors; Tandem Mass Spectrometry

To compare the cardiorespiratory, gastrointestinal, analgesic, and behavioral effects between IV and IM administration of morphine in conscious horses with no signs of pain.. 6 healthy adult horses.. Horses received saline (0.9% NaCl) solution (IM or IV) or morphine sulfate (0.05 and 0.1 mg/kg, IM or IV) in a randomized, masked crossover study design. The following variables were measured before and for 360 minutes after drug administration: heart and respiratory rates; systolic, diastolic, and mean arterial blood pressures; rectal temperature; arterial pH and blood gas variables; intestinal motility; and response to thermal and electrical noxious stimuli. Adverse effects and horse behavior were also recorded. Plasma concentrations of morphine, morphine-3-glucuronide, and morphine-6-glucuronide were measured via liquid chromatography-mass spectrometry.. No significant differences in any variable were evident after saline solution administration. Intravenous and IM administration of morphine resulted in minimal and short-term cardiorespiratory, intestinal motility, and behavioral changes. A decrease in gastrointestinal motility was detected 1 to 2 hours after IM administration of morphine at doses of 0.05 and 0.1 mg/kg and after IV administration of morphine at a dose of 0.1 mg/kg. Morphine administration yielded no change in any horse's response to noxious stimuli. Both morphine-3-glucuronide and morphine-6-glucuronide were detected in plasma after IV and IM administration of morphine.. Clinically relevant doses of morphine sulfate yielded minimal and short-term behavioral and intestinal motility effects in healthy horses with no signs of pain. Neither dose of morphine affected their response to a noxious stimulus.

Topics: Analysis of Variance; Animals; Body Temperature; Cross-Over Studies; Gastrointestinal Motility; Heart Rate; Horses; Injections, Intramuscular; Injections, Intravenous; Morphine; Morphine Derivatives; Motor Activity; Pain Threshold; Respiratory Rate

Although intravenous morphine titration (IMT) is widely used to control moderate to severe postoperative pain, the relationships between plasma concentrations of morphine and its metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), and IMT outcomes in the postanesthesia care unit (PACU) have not been yet investigated. IMT was administrated as a bolus of 2 or 3 mg every 5 min. Titration was interrupted in case of pain relief (visual analog score ≤30), adverse events, sedation, or failure of morphine titration. Blood samples were collected at the end of morphine titration to determine plasma concentration of morphine and its two metabolites. Data from 214 patients were analyzed; 143 (67%) of the patients achieved complete pain relief, 39 (18%) experienced adverse events, and 32 (15%) failure of morphine titration. At the end of titration, there were no significant differences in morphine, M6G, M3G concentrations between sedated and nonsedated patients (32 vs. 42 ng/mL (P = 0.07), 38 vs. 45 ng/mL (P = 0.51), 300 vs. 342 ng/mL (P = 0.29), respectively), or patients with or without adverse events (40 vs. 41 ng/mL (P = 0.95), 37 vs. 46 ng/mL (P = 0.51), 287 vs. 340 ng/mL (P = 0.72), respectively). Our study demonstrated a lack of relationship between plasma concentrations or ratios of morphine, M3G, and M6G, with IMT outcomes in PACU. This result suggests that the kinetics of morphine and its metabolites have limited value for explaining clinical effects of morphine in this clinical setting.

Topics: Age Factors; Aged; Female; Humans; Injections, Intravenous; Male; Middle Aged; Morphine; Morphine Derivatives; Obesity; Pain Measurement; Pain, Postoperative; Postoperative Care; Sex Characteristics; Treatment Failure; Treatment Outcome

Individual variation in opioid response is considerable, partly due to pharmacokinetic factors. Transporter proteins are becoming increasingly interesting also in the pharmacokinetics of opioids. The efflux transporter P-glycoprotein can affect gastrointestinal absorption and tissue distribution, particularly brain access of many opioids. The aim of this study was to evaluate whether itraconazole, which is a potent inhibitor of P-glycoprotein and CYP3A4, would change the pharmacokinetics or the pharmacodynamics of oral morphine.. Twelve healthy male volunteers ingested, in a randomized crossover study, once daily 200 mg itraconazole or placebo for 4 days. On day 4, 1 h after the last pre-treatment dose, the subjects ingested 0.3 mg/kg morphine. Blood samples for the determination of plasma morphine, morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G) and itraconazole concentrations were drawn up to 48 h after morphine ingestion. Pharmacodynamic effects were evaluated using a questionnaire, visual analogue scales, a reaction time test, the Digit Symbol Substitution Test and the Critical Flicker Fusion Test.. Itraconazole increased the mean area under the plasma concentration-time curve [AUC (0-9)] of morphine by 29% (P=0.002), its AUC (0-48) by 22% (P=0.013) and its peak plasma concentration by 28% (P=0.035). Itraconazole did not significantly affect the pharmacokinetic variables of M3G or M6G or the pharmacodynamic effects of morphine.. Itraconazole moderately increases plasma concentrations of oral morphine, probably by enhancing its absorption by inhibiting intestinal wall P-glycoprotein. A possible improvement of morphine penetration to the brain could not be observed.

Topics: Administration, Oral; Adult; Analgesics, Opioid; Antifungal Agents; Area Under Curve; ATP Binding Cassette Transporter, Subfamily B, Member 1; Central Nervous System Stimulants; Cross-Over Studies; Double-Blind Method; Humans; Itraconazole; Male; Morphine; Morphine Derivatives; Oxygen; Pain Measurement; Research Design

The aim was to evaluate the clinical effectiveness, pharmacodynamics and pharmacokinetics of a range of Tincture of Opium (TOP) doses in the management of opioid withdrawal.. Forty-five opium-dependent Thai subjects were allocated to three dosing groups (6.66, 13.3 and 20 mg morphine equivalents, twice daily) depending on their self-reported prior opium use. On day 5 of dosing subjects underwent an interdosing interval study where blood, withdrawal scores, heart rate and blood pressure (BP) were collected at 0, 1, 3 and 8 h. Plasma morphine concentrations were quantified by high-performance liquid chromatography, and plasma morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) concentrations by LCMS.. Thirty-two subjects completed the study. Withdrawal scores were low for all subjects (range 9-23% of maximum response). There were dose-dependent changes in both systolic and diastolic BP (P = 0.021 and P = 0.01, respectively), but these were not considered clinically significant. There were no effects of dose on respiratory rate. Plasma morphine concentrations changed significantly across the interdosing interval (P = 0.0001), rising to a maximum at 1 h after dosing. Plasma morphine concentrations also differed according to dose (P < 0.05). The mean ratios of the morphine glucuronides were found to be: M3G/M6G = 7.7, M3G/morphine = 35.6 and M6G/morphine = 4.9, values comparable to those previously reported.. The management of opioid withdrawal can be achieved, with minimal adverse effects, by using flexible dosing of TOP.

Topics: Adolescent; Adult; Analysis of Variance; Blood Pressure; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Male; Middle Aged; Morphine; Morphine Dependence; Morphine Derivatives; Narcotics; Respiration; Substance Withdrawal Syndrome; Thailand; Treatment Outcome; Young Adult

Codeine is an analgesic drug acting on mu-opiate receptors predominantly via its metabolite morphine, which is formed almost exclusively by the genetically polymorphic enzyme cytochrome P450 2D6 (CYP2D6). Whereas it is known that individuals lacking CYP2D6 activity (poor metabolizers, PM) suffer from poor analgesia from codeine, ultra-fast metabolizers (UM) due to the CYP2D6 gene duplication may experience exaggerated and even potentially dangerous opioidergic effects and no systematical study has been performed so far on this question. A single dose of 30 mg codeine was administered to 12 UM of CYP2D6 substrates carrying a CYP2D6 gene duplication, 11 extensive metabolizers (EM) and three PM. Genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism methods and a single-base primer extension method for characterization of the gene-duplication alleles. Pharmacokinetics was measured over 24 h after drug intake and codeine and its metabolites in plasma and urine were analyzed by liquid chromatography with tandem mass spectrometry. Significant differences between the EM and UM groups were detected in areas under the plasma concentration versus time curves (AUCs) of morphine with a median (range) AUC of 11 (5-17) microg h l(-1) in EMs and 16 (10-24) microg h l(-1) in UM (P=0.02). In urine collected over 12 h, the metabolic ratios of the codeine+codeine-6-glucuronide divided by the sum of morphine+its glucuronides metabolites were 11 (6-17) in EMs and 9 (6-16) in UM (P=0.05). Ten of the 11 CYP2D6 UMs felt sedation (91%) compared to six (50%) of the 12 EMs (P=0.03). CYP2D6 genotypes predicting ultrarapid metabolism resulted in about 50% higher plasma concentrations of morphine and its glucuronides compared with the EM. No severe adverse effects were seen in the UMs in our study most likely because we used for safety reasons a low dose of only 30 mg. It might be good if physicians would know about the CYP2D6 duplication genotype of their patients before administering codeine.

Topics: Administration, Oral; Adult; Analgesics, Opioid; Area Under Curve; Biotransformation; Codeine; Consciousness; Cytochrome P-450 CYP2D6; Dealkylation; Gene Duplication; Genotype; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Phenotype; Reference Values

After oral administration, morphine-6-glucuronide (M6G) displays an atypical absorption profile with two peak plasma concentrations. A proposed explanation is that M6G is hydrolysed to morphine in the colon, which is then absorbed and subsequently undergoes metabolism in the liver to morphine-3-glucuronide (M3G) and M6G. The aims of this study were to confirm and elucidate the biphasic absorption profile as well as clarify the conversion of M6G to morphine after a single oral administration of M6G in healthy volunteers.. The study was conducted accordingly to a nonblinded, randomised, balanced three-way crossover design in eight healthy male subjects. The subjects received 200 mg oral M6G, 50 mg oral M6G and 30 mg oral morphine. Blood samples were collected until 72 h after M6G administration and until 9 h after morphine administration. Paracetamol and sulfasalazine were coadministered with M6G as markers for the gut contents reaching the duodenum and colon, respectively.. The plasma concentration peaks of M6G were seen at 4.0 (2.0-6.0) and 18 (12.0-24.0) h after 200 mg M6G and at 3.5 (2.0-6.0) and 21.3 (10.0-23.3) h after 50 mg M6G, which was in agreement with previously published results. The K(M6G_abs)/K(M6G_M6G) ratio was found to be 10.. The pharmacokinetic profile of M6G after oral administration was confirmed and with the presence of M3G and morphine in plasma after oral administration of M6G, proof seems to be found of the constant and prolonged absorption of M6G. The K(M6G_abs)/K(M6G_M6G) ratio of 10 indicates that the second absorption peak of M6G consists of approximately 10 times more absorbed M6G than reglucuronidated M6G. However, further studies are required to determine the precise kinetics of the second absorption peak.

Topics: Absorption; Administration, Oral; Adolescent; Adult; Analgesics, Opioid; Cross-Over Studies; Humans; Hydrolysis; Male; Morphine; Morphine Derivatives

To compare the time course of morphine and metabolite concentrations in serum and cerebrospinal fluid (CSF) after intravenous and intramuscular administration after surgery.. This was a randomized double-blind, double-dummy study in patients who had undergone hip replacement surgery. Morphine (M, 10 mg) was administered intravenously (IV) or intramuscularly (IM). Arterial blood and CSF samples (from a spinal catheter) were drawn simultaneously at 10, 30, 60, and 120 min after administration. Morphine and metabolites [morphine-3-glucuronide (M-3-G), morphine-6-glucuronide (M-6-G), and normorphine (NM)] were determined by a validated liquid chromatography-tandem mass spectrometry method.. Thirty-eight patients were included: 13 men and 25 women, 20 in the IV, 18 in the IM group. Serum concentrations of M after 10 min were consistently higher after IM than IV, concentrations of M-3-G and M-6-G after IM surpassed those of IV after 45 min. NM was not found. None of the metabolites was found in CSF. CSF morphine concentrations and CSF/serum concentration ratios were consistently higher after IV compared to IM. The mean AUC(CSF)/AUC(serum) (0-120 min) concentration ratios were 0.18 and 0.09 after IV and IM, respectively.. The uptake of morphine to the CSF was consistently higher after IV administration than after IM already after 10 min. The higher CSF concentration may be caused by an initially higher morphine blood/CSF gradient following IV morphine injection. The pharmacokinetic findings are compatible with a more rapid and extensive initial effect of IV morphine compared with IM.

Topics: Aged; Analgesics, Opioid; Area Under Curve; Arthroplasty, Replacement, Hip; Bupivacaine; Double-Blind Method; Female; Humans; Injections, Intramuscular; Injections, Intravenous; Male; Midazolam; Middle Aged; Morphine; Morphine Derivatives; Pain Measurement; Pain, Postoperative; Postoperative Care

In several European countries and in Canada, clinical trials are being conducted in which heroin-addicted patients are treated with pharmaceutically prepared heroin in order to reduce the destructive behaviour that is so often associated with this drug.. To develop an integrated population pharmacokinetic model for heroin (diamorphine) and its pharmacodynamically active metabolites 6-acetylmorphine, morphine, morphine-3-glucuronide and morphine-6-glucuronide. Additionally, the influence on heroin pharmacokinetics of several covariates that are typical for this population was determined.. Plasma concentration data from 106 heroin-dependent patients in The Netherlands (74 heroin inhalers and 32 injectors) were obtained. The 'chasing the dragon' technique was used for inhalation, in which the fumes of heroin base, heated on aluminum foil, were inhaled. Heroin doses varied between 66 and 450 mg. Heroin, 6-acetylmorphine and morphine data were fitted simultaneously using sequential two-compartment models. Morphine-3-glucuronide and morphine-6-glucuronide data were fitted separately to one-compartment models. All data analysis was performed using nonlinear mixed-effect modelling.. The bioavailability of inhaled heroin was estimated to be 53% (95% CI 43.7, 62.3). The terminal half-lives of heroin and 6-acetylmorphine were estimated to be 7.6 and 21.8 minutes, respectively. The clearances of morphine and the morphine-glucuronides were estimated to be 73.6 L/h (95% CI 62.8, 84.4) and between 6 and 10 L/h, respectively. The terminal half-life of 6-acetylmorphine was 13% lower in cocaine users (p < 0.05). No other significant relationships between covariates and pharmacokinetic parameters were discovered.. Pharmacokinetic parameters of heroin and its five major metabolites were assessed simultaneously in one integrated model. Covariate analyses revealed that sex, bodyweight, benzodiazepine use and creatinine clearance (>60 mL/min) do not need to be taken into account in the medical prescription of pharmaceutically prepared heroin for the treatment of heroin dependency.

Topics: Administration, Inhalation; Adult; Analgesics, Opioid; Biological Availability; Female; Heroin; Heroin Dependence; Humans; Injections, Intravenous; Male; Middle Aged; Models, Biological; Morphine; Morphine Derivatives; Narcotics; Netherlands

Morphine-6-glucuronide (M6G) is a metabolite of morphine and a micro-opioid agonist. To quantify the potency and speed of onset-offset of M6G and explore putative sex dependency, the authors studied the pharmacokinetics and pharmacodynamics of M6G in volunteers using a placebo-controlled, randomized, double-blind study design.. Ten men and 10 women received 0.3 mg/kg intravenous M6G and placebo (two thirds of the dose as bolus, one third as a continuous infusion over 1 h) on separate occasions. For 7 h, pain tolerance was measured using gradually increasing transcutaneous electrical stimulation, and blood samples were obtained. A population pharmacokinetic (inhibitory sigmoid Emax)-pharmacodynamic analysis was used to analyze M6G-induced changes in tolerated stimulus intensity. The improvement in model fits by inclusion of covariate sex was tested for significance. P values less than 0.01 were considered significant. Taking into account previous morphine data, a predictive pharmacokinetic-pharmacodynamic model was constructed to determine the contribution of M6G to morphine analgesia.. M6G concentrations did not differ between men and women. M6G caused analgesia significantly greater than that observed with placebo (P < 0.01). The M6G analgesia data were well described by the pharmacokinetic-pharmacodynamic model. The M6G effect site concentration causing a 25% increase in current (C25) was 275 +/- 135 nm (population estimate +/- SE), the blood effect site equilibration half-life was 6.2 +/- 3.3 h, and the steepness parameter was 0.71 +/- 0.18. Intersubject variability was 167% for C25 and 218% for the effect half-life. None of the model parameters showed sex dependency.. A cumulative dose of 0.3 mg/kg M6G, given over 1 h, produces long-term analgesia greater than that observed with placebo, with equal dynamics (potency and speed of onset-offset) in men and women. Possible causes for the great intersubject response variability, such as genetic polymorphism of the micro-opioid receptor and placebo-related phenomena, are discussed. The predictive pharmacokinetic-pharmacodynamic model was applied successfully and was used to estimate M6G analgesia after morphine in patients with normal and impaired renal function.

Topics: Adult; Algorithms; Analgesia; Analgesics, Opioid; Area Under Curve; Bayes Theorem; Electric Stimulation; Female; Humans; Infusions, Intravenous; Male; Models, Biological; Morphine; Morphine Derivatives; Pain; Pain Measurement; Receptors, Opioid, mu; Sex Characteristics

Descriptions of the pharmacokinetics and metabolism of morphine and its metabolites in young children are scant. Previous studies have not differentiated the effects of size from those related to age during infancy.. Postoperative children 0-3 yr old were given an intravenous loading dose of morphine hydrochloride (100 micro g kg(-1) in 2 min) followed by either an intravenous morphine infusion of 10 micro g h(-1) kg(-1) (n=92) or 3-hourly intravenous morphine boluses of 30 micro g kg(-1) (n=92). Additional morphine (5 micro g kg(-1)) every 10 min was given if the visual analogue (VAS, 0-10) pain score was >/=4. Arterial blood (1.4 ml) was sampled within 5 min of the loading dose and at 6, 12 and 24 h for morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G). The disposition of morphine and formation clearances of morphine base to its glucuronide metabolites and their elimination clearances were estimated using non-linear mixed effects models.. The analysis used 1856 concentration observations from 184 subjects. Population parameter estimates and their variability (%) for a one-compartment, first-order elimination model were as follows: volume of distribution 136 (59.3) litres, formation clearance to M3G 64.3 (58.8) litres h(-1), formation clearance to M6G 3.63 (82.2) litres h(-1), morphine clearance by other routes 3.12 litres h(-1) per 70 kg, elimination clearance of M3G 17.4 (43.0) litres h(-1), elimination clearance of M6G 5.8 (73.8) litres h(-1). All parameters are standardized to a 70 kg person using allometric 3/4 power models and reflect fully mature adult values. The volume of distribution increased exponentially with a maturation half-life of 26 days from 83 litres per 70 kg at birth; formation clearance to M3G and M6G increased with a maturation half-life of 88.3 days from 10.8 and 0.61 litres h(-1) per 70 kg respectively at birth. Metabolite formation decreased with increased serum bilirubin concentration. Metabolite clearance increased with age (maturation half-life 129 days), and appeared to be similar to that described for glomerular filtration rate maturation in infants.. M3G is the predominant metabolite of morphine in young children and total body morphine clearance is 80% that of adult values by 6 months. A mean steady-state serum concentration of 10 ng ml(-1) can be achieved in children after non-cardiac surgery in an intensive care unit with a morphine hydrochloride infusion of 5 micro g h(-1) kg(-1) at birth (term neonates), 8.5 micro g h(-1) kg(-1) at 1 month, 13.5 micro g h(-1) kg(-1) at 3 months and 18 micro g h(-1) kg(-1) at 1 year and 16 micro g h(-1) kg(-1) for 1- to 3-yr-old children.

Topics: Aging; Analgesics, Opioid; Body Weight; Child, Preschool; Drug Administration Schedule; Female; Half-Life; Humans; Infant; Infant, Newborn; Male; Models, Biological; Morphine; Morphine Derivatives; Pain, Postoperative; Single-Blind Method

A number of studies have reported the analgesic effect of morphine when applied topically to painful skin ulcers. It has been suggested that morphine may exert a local action, as opioid receptors have been demonstrated on peripheral nerve terminals. In this study, we investigated the bioavailability of topically applied morphine to cutaneous ulcers. Six hospice inpatients with skin ulcers were given morphine sulfate 10 mg in Intrasite gel topically and morphine sulfate 10 mg subcutaneously over 4 hours, at least 48 hours apart, in randomized order. Morphine, morphine-6-glucuronide (M6G), and morphine-3-glucuronide (M3G) were determined in plasma using a specific HPLC method. In five patients morphine and its metabolites were undetectable when applied topically. In one patient (with the largest ulcer), morphine and M6G were detected. The calculated morphine and M6G bioavailability in this patient were 20% and 21%, respectively. M3G was also detected but was below the lower limit of quantitation. When applied topically to ulcers, morphine was not absorbed in the majority of patients, suggesting any analgesic effect would be mediated locally rather than systemically. However, in ulcers with a large surface area, systemic absorption may occur.

Topics: Administration, Topical; Aged; Aged, 80 and over; Analgesics, Opioid; Biological Availability; Female; Humans; Male; Metabolic Clearance Rate; Middle Aged; Morphine; Morphine Derivatives; Pain; Skin Ulcer

To study the influence of morphine on chemical control of breathing relative to the analgesic properties of morphine, the authors quantified morphine-induced analgesia and respiratory depression in a single group of healthy volunteers. Both respiratory and pain measurements were performed over single 24-h time spans.. Eight subjects (four men, four women) received a 90-s intravenous morphine infusion; eight others (four men, four women) received a 90-s placebo infusion. At regular time intervals, respiratory variables (breathing at a fixed end-tidal partial pressure of carbon dioxide of 50 mmHg and the isocapnic acute hypoxic response), pain tolerance (derived from a transcutaneous electrical acute pain model), and arterial blood samples were obtained. Data acquisition continued for 24 h. Population pharmacokinetic (sigmoid Emax)-pharmacodynamic models were applied to the respiratory and pain data. The models are characterized by potency parameters, shape parameters (gamma), and blood-effect site equilibration half-lives. All collected data were analyzed simultaneously using the statistical program NONMEM.. Placebo had no systematic effect on analgesic or respiratory variables. Morphine potency parameter and blood-effect site equilibration half-life did not differ significantly among the three measured effect parameters (P > 0.01). The integrated NONMEM analysis yielded a potency parameter of 32 +/- 1.4 nm (typical value +/- SE) and a blood-effect site equilibration half-life of 4.4 +/- 0.3 h. Parameter gamma was 1 for hypercapnic and hypoxic breathing but 2.4 +/- 0.7 for analgesia (P < 0.01).. Our data indicate that systems involved in morphine-induced analgesia and respiratory depression share important pharmacodynamic characteristics. This suggests similarities in central mu-opioid analgesic and respiratory pathways (e.g., similarities in mu-opioid receptors and G proteins). The clinical implication of this study is that after morphine administration, despite lack of good pain relief, moderate to severe respiratory depression remains possible.

Topics: Adolescent; Adult; Algorithms; Analgesics, Opioid; Carbon Dioxide; Double-Blind Method; Female; Half-Life; Humans; Hypoxia; Injections, Intravenous; Male; Models, Statistical; Morphine; Morphine Derivatives; Pain Measurement; Respiratory Function Tests; Respiratory Mechanics

In order to make treatment decisions physicians should have knowledge about the relations between patient characteristics and drug disposition. Dose, route of administration, gender, age and renal function are reported to influence the serum concentrations of morphine, morphine-6-glucurnide (M6G) and morphine-3-glucuronide (M3G) during chronic treatment of cancer pain. These factors, however, are not evaluated in studies with a sample size sufficient to explore predictive factors.. Three hundred consecutive morphine users admitted because of a malignant disease were recruited. The relations of serum concentrations of morphine, M6G and M3G to patient characteristics (gender, age, weight, renal function, liver function, dose, route of administration) were explored, and regression analysis performed to investigate whether these characteristics predicted serum concentrations obtained during routine clinical drug monitoring.. Morphine dose was associated with serum concentrations of morphine (r = 0.69), M6G (r = 0.76) and M3G (r = 0.76). Oral morphine resulted in higher dose-adjusted M6G and M3G serum concentrations compared with s.c. morphine. Creatinine serum concentrations correlated with serum concentrations of M6G and M3G. Dose and route of administration predicted morphine serum concentrations, while dose and renal function predicted M6G and M3G serum concentrations. Age was an additional factor predicting M3G concentrations. Dose was the only factor that explained a clinically significant part of the observed variability.. Patient characteristics predict only minor parts of the variability of morphine, M3G and M6G serum concentrations observed during routine clinical drug-monitoring in cancer patients.

Topics: Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Biotransformation; Delayed-Action Preparations; Drug Monitoring; Female; Humans; Infusions, Intravenous; Liver Function Tests; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Prospective Studies

We investigated the variation in the uridine diphosphate-glucuronosyltransferase 2B7 (UGT2B7) gene in patients receiving patient-controlled analgesia with morphine. UGT2B7 was sequenced in phenotypic extremes (n = 12) of the distribution of morphine-6-glucuronide/morphine plasma ratios. A new -161C/T promoter variant was in complete linkage disequilibrium with the 802C/T variant and was more frequent in low glucuronidators (P =.039). Both variants were genotyped in all patients (n = 86), and complete linkage disequilibrium was confirmed. Trend analysis showed reduced morphine-6-glucuronide/morphine ratios in patients with T/T, C/T, and C/C genotypes (T/T > C/T > C/C) (P =.031). Morphine levels were lower in T/T patients (median, 18 ng/mL [range, 18-1490 ng/mL]) as compared with C/T and C/C patients combined (median, 66 ng/m; range, 18-3995 ng/mL) (P =.04). Morphine-6-glucuronide and morphine-3-glucuronide concentrations were significantly lower in C/C patients (median, 18 ng/mL; range, 0-66 ng/mL; and median, 152 ng/mL; range, 30-434 ng/mL; respectively) compared with C/T and T/T patients combined (median, 43 ng/mL; range, 0-193 ng/mL; and median, 242 ng/mL; range, 33-1381 ng/mL; respectively) (P =.045 and P =.004, respectively). Interindividual differences in morphine glucuronidation may be the result of genetic variation in UGT2B7, and further studies are indicated.

Topics: Adult; Aged; Aged, 80 and over; Analgesia, Patient-Controlled; Analgesics, Opioid; Biotransformation; Black People; Female; Genotype; Glucuronosyltransferase; Humans; Indicators and Reagents; Male; Middle Aged; Morphine; Morphine Derivatives; Phenotype; White People

In 25 cancer patients treated with slow-release oral morphine and in 10 cancer patients treated with continuous infusion of morphine, plasma steady-state concentrations of morphine (M), morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G) were determined by high-performance liquid chromatography. Blood samples were withdrawn at 0, 2 and 6 h after oral administration in patients treated with slow-release oral morphine and once or twice a day in patients treated with continuous infusion of morphine. In four cancer patients treated with continuous infusion of morphine, in order to analyze chronopharmacokinetic variability, the M-3-G/M ratio was observed at 12:00 h and 24:00 h. No significant changes were observed in M-3-G/M ratios and M-6-G ratios at 0, 2, and 6 h after oral administration of morphine. The M-3-G/M ratio (38.6 +/- 25.7) in the oral morphine group was significantly higher than that (15.3 +/- 12.9) in the continuous infusion group (p < 0.01). There was an approximately 10-fold interindividual variation in the M-3-G/M ratio both in the continuous infusion group and in the oral morphine group. These results suggest that the activity of UDP glucuronosyltransferase 2B7 in the intestinal metabolism of morphine may play an active part in a large interindividual variation in the ratio of metabolites to morphine. Further studies are needed to clarify this hypothesis.

Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Alanine Transaminase; Aspartate Aminotransferases; Chromatography, High Pressure Liquid; Delayed-Action Preparations; Humans; Infusions, Intravenous; Liver; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Tablets

UDP-glucuronosyltransferase (UGT) 2B7 is the major UGT isoform responsible for the 3- and 6-glucuronidation of morphine in humans. Studies in rats have indicated that UGT1A1 may also contribute to the formation of morphine 3-glucuronide (M3G). Our objective was to investigate whether the UGT2B7 H268Y and UGT1A1*28 polymorphisms contribute to the variability in morphine glucuronide-to-morphine plasma ratios among cancer patients undergoing analgesic therapy with morphine.. Seventy patients with normal hepatic and renal function using slow-release morphine to relieve cancer pain were included. UGT2B7 genotyping was performed using restriction enzyme analysis of polymerase chain reaction (PCR)-amplified DNA fragments. Wild-type and variant alleles of the UGT1A1 gene were identified using sizing of PCR-amplified fragments. Morphine 6-glucuronide (M6G)/morphine, M3G/morphine, and M3G/M6G plasma ratios were compared between genotypes.. The M3G/morphine, M6G/morphine, and M3G/M6G plasma ratios varied 16-, 42-, and sevenfold, respectively, among individuals. No statistically significant differences in plasma ratios were found between individuals possessing UGT2B7 H/H ( n=20), H/Y ( n=30), or Y/Y ( n=20) genotypes. Five patients were homozygous for the UGT1A1 TA(7) allele, which is associated with reduced UGT1A1 gene expression. However, the mean M3G/M6G and M3G/morphine plasma ratios in TA(7) homozygous subjects did not differ significantly from those of heterozygous or homozygous wild-type (TA(6)) individuals.. The UGT2B7 H268Y polymorphism cannot account for the considerable variation in glucuronide-to-morphine ratios in cancer patients. Moreover, the contribution of UGT1A1 to the formation of M3G appears to be of minor biological significance, at least in a UGT2B7 background.

Topics: Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Genotype; Glucuronosyltransferase; Humans; Isoenzymes; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Reverse Transcriptase Polymerase Chain Reaction

Codeine analgesia is wholly or mostly due to its metabolism to morphine by the cytochrome P450 enzyme CYP2D6, which shows significant genetic variation in activity. The aims of this study were to investigate genotype, phenotype and morphine production from codeine in children undergoing adenotonsillectomy, and to compare analgesia from codeine or morphine combined with diclofenac.. Ninety-six children received either codeine 1.5 mg kg(-1) or morphine 0.15 mg kg(-1) in a randomized, double-blind design. Genetic analysis was performed and plasma morphine concentrations at 1 h were determined. Postoperative analgesia and side-effects were recorded.. Forty-seven per cent of children had genotypes associated with reduced enzyme activity. Mean (SD) morphine concentrations were significantly lower (P<0.001) after codeine [4.5 (0.3) ng ml(-1)] than after morphine [24.7 (1.5) ng ml(-1)], and morphine and its metabolites were not detected in 36% of children given codeine. There was a significant relationship between phenotype and plasma morphine (P=0.02). More children required rescue analgesia after codeine at both 2 (P<0.05) and 4 h after administration (P<0.01). Fifty-six per cent of children vomited after morphine and 29% after codeine (P<0.01). Neither phenotype nor morphine concentration was correlated with either pain score or the need for rescue analgesia (r=-0.21, 95% confidence interval -0.4, -0.01).. Reduced ability for codeine metabolism may be more common than previously reported. Plasma morphine concentration 1 h after codeine is very low, and related to phenotype. Codeine analgesia is less reliable than morphine, but was not well correlated with either phenotype or plasma morphine in this study.

Topics: Analgesia; Analgesics, Opioid; Anti-Inflammatory Agents, Non-Steroidal; Central Nervous System Stimulants; Child; Child, Preschool; Codeine; Diclofenac; Double-Blind Method; Female; Genotype; Humans; Male; Morphine; Morphine Derivatives; Phenotype; Tonsillectomy; Urban Population; Vomiting

Morphine sulfate extended-release (MSER) uses a drug-delivery technology that allows once-daily dosing. It is possible to open the MSER capsule and sprinkle the contents on soft food, a potentially useful alternative to the intact capsule in patients who have difficulty swallowing.. This study compared the bioavailability of MSER and its metabolites morphine-3-glucuronide and morphine-6-glucuronide after administration of MSER in a sprinkle-dose regimen relative to an intact capsule swallowed whole.. This was a randomized, open-label, single-dose, crossover study, with a 7-day washout period between the 2 dosing days. Healthy volunteers were randomized to receive an intact 60-mg MSER capsule swallowed whole or the contents of a 60-mg MSER capsule sprinkled on applesauce. Blood samples were collected and analyzed for concentrations of morphine and its active glucuronide metabolites. Pharmacokinetic (PK) parameters were calculated and bioequivalence assessed. Bioequivalence was concluded if the 90% CIs of the ratio of log-transformed values for maximum concentration (Cmax) and area under the plasma concentration-time curve (AUC) were within 80% to 125%.. Of 30 subjects enrolled, 28 completed the study and were eligible for PK evaluation. Two subjects were withdrawn for reasons unrelated to study treatment. The plasma concentration-time profiles of morphine and its metabolites were superimposable after administration of the 2 regimens. Cmax and total systemic exposure-based on AUC from time 0 to the last quantifiable concentration (AUC(last)) and AUC from time 0 to infinity (AUC(infinity))-were comparable between treatments. The 90% CIs for morphine AUC(last), AUC, and Cmax ratios were 98 to 109, 96 to 106, and 95 to 117, respectively. Similar 90% CIs were obtained for the morphine metabolites.. In this study in healthy volunteers, sprinkling the entire contents of an MSER capsule onto applesauce and swallowing without chewing was bioequivalent to swallowing an intact MSER capsule.

Topics: Adult; Biological Availability; Cross-Over Studies; Delayed-Action Preparations; Female; Humans; Male; Morphine; Morphine Derivatives

The purpose of this investigation was to study the influence of ondansetron on the single-dose pharmacokinetics and the analgesic effects elicited by morphine and the 3- and 6-glucuronide metabolites of morphine in healthy volunteers.. This was a randomized, double-blind, placebo-controlled, two-way crossover study in which six male and six female subjects were administered a single 10 mg intravenous dose of morphine sulphate, followed 30 min later by a single 16 mg intravenous dose of ondansetron hydrochloride or placebo. Serum and urine concentrations of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) samples were quantified over 48 h using high performance liquid chromatography with detection by mass spectrometry. Analgesia was assessed in the volunteers with a contact thermode device to provide a thermal pain stimulus. Four analgesic response variables were measured including thermal pain threshold, thermal pain tolerance, temporal summation of pain and mood state.. The two treatments appeared to be equivalent based on the 90% confidence intervals (0.6, 1.67) of the least squares means ratio. All least squares means ratio confidence intervals for each parameter, for each analyte fell within the specified range, demonstrating a lack of an interaction.. The results of this study suggest that administration of ondansetron (16 mg i.v.) does not alter the pharmacokinetics of morphine and its 3- or 6-glucuronide metabolites to a clinically significant extent, nor does it affect the overall analgesic response to morphine as measured by the contact thermode system.

Topics: Adolescent; Adult; Analgesics, Opioid; Cross-Over Studies; Double-Blind Method; Drug Interactions; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Ondansetron; Pain Measurement; Placebos; Serotonin Antagonists

To investigate the pharmacokinetics of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) in healthy volunteers after the administration of morphine by subcutaneous bolus injection (s.c.b.) and subcutaneous infusion (s.c. i.) over 4 h, and to compare the results with the intravenous bolus (i.v.) administration of morphine.. Six healthy volunteers each received 5 mg morphine sulphate by i.v., s.c.b. and short s.c.i. over 4 h, on three separate occasions, in random order, each separated by at least 1 week. Plasma samples were assayed for morphine, M6G and M3G.. After i.v. morphine, the concentrations of morphine, M6G and M3G and their pharmacokinetic parameters were similar to those we have observed previously, in other healthy volunteers (when standardized to nmol l- 1, for a 10 mg dose to a 70 kg subject). After s.c.b. morphine, similar results were obtained except that the median tmax values for morphine and M3G were significantly longer than after i.v. morphine (P< 0.001 and P< 0.05, respectively), with a trend to a longer tmax for M6G (P = 0. 09). The appearance half-lives after s.c.b. morphine for M6G and M3G were also significantly longer than after i.v. morphine (P = 0.03 and P< 0.05, respectively). Comparison of log-transformed AUC values indicated that i.v. and s.c.b. administration of morphine were bioequivalent with respect to morphine, M6G and M3G. In comparison with i.v. morphine, morphine by s.c.i. was associated with significantly longer median tmax values for morphine (P< 0.001), M6G (P< 0.001) and M3G (P< 0.05), and the mean standardized Cmax values significantly lower than after both i.v. and s.c.b. morphine (morphine P< 0.001, M6G P< 0.001 and M3G P< 0.01 for each comparison). Comparison of log-transformed AUC values after i.v. and s.c.i. morphine indicated that the two routes were not bioequivalent for morphine (log-transformed AUC ratio 0.78, 90% CI 0.66-0.93), M6G (0.72, 90% CI 0.63-0.82), or M3G (0.65, 90% CI 0.54-0.78). A small stability study indicated no evidence of adsorptive losses from morphine infused over 4 h using the infusion devices from the study.. Although bioequivalence was demonstrated between the s. c.b. and i.v. routes of morphine administration, the bioavailabilities of morphine, M6G and M3G after s.c.i. were significantly lower than after i.v. administration. However, despite this, the study demonstrates that the subcutaneous route is an effective method for the parenteral administration of morphine.

Topics: Adult; Analgesics, Opioid; Drug Stability; Female; Humans; Infusions, Intravenous; Injections, Subcutaneous; Male; Morphine; Morphine Derivatives

We compared analgesic effects and pharmacokinetics of intraarticular versus intravenous administration of morphine after arthroscopic anterior cruciate ligament surgery. In a double-blind placebo-controlled study, 40 patients were randomly allocated to one of four treatment groups. Group I received 1 mg morphine intraarticularly and saline intravenously; group II received 5 mg morphine intraarticularly and saline intravenously; group III received 5 mg saline intraarticularly and morphine intravenously and group IV, the control group, received saline both intraarticularly and intravenously. The pain scores were significantly lower in groups I and II at 24 hours postoperatively than in group IV, and in group II during the rest of the postoperative period, as compared to groups III and IV. After intraarticular injection of 1 mg and 5 mg morphine, respectively, low concentrations of morphine-6-glucuronide (M6G) were found in the circulation, while morphine-3-glucuronide (M3G) appeared late after the injection in concentrations that considerably exceeded those of morphine in groups I and II. The analgesic effect of intraarticular morphine together with the low levels of morphine and morphine-6-glucuronide in plasma further strengthens the view that opioids have a peripheral mechanism of action.

Topics: Adolescent; Adult; Analgesics, Opioid; Anterior Cruciate Ligament; Arthroscopy; Double-Blind Method; Female; Humans; Injections, Intra-Articular; Injections, Intravenous; Male; Morphine; Morphine Derivatives; Pain Measurement; Pain, Postoperative; Prospective Studies

To compare the efficacy, safety and pharmacokinetics of a newly developed controlled-release suppository (MSR) with MS Contin tablets (MSC) in cancer patients with pain.. In a double-blind, randomised, two-way cross-over trial, 25 patients with cancer pain were selected with a morphine (M) demand of 30 mg every 12 h. Patients were divided into two groups. Group 1 received active MSC (30 mg) and placebo MSR, followed by placebo MSC and active MSR (30 mg) each for a period of 5 days. Group 2 started with active MSR and placebo MSC, followed by active MSC and placebo MSR, each for a period of 5 days. Blood for determination of plasma concentration of morphine (M) and its 3- and 6-glucuronides (M3G, M6G) was collected, and area under the plasma concentration-time curve (AUC)0-12 h, peak plasma concentration (Cmax), time to reach Cmax (tmax), and CO and C12 of M, M6G and M3G were determined on day 5 and day 10. Intensity of pain experienced by each patient was assessed every 2 h on a 0-10 scale, while side effects and rescue medication were recorded.. Twenty patients (ten patients in each group) completed the study. A pronounced inter-patient variability in plasma concentrations of M, M3G and M6G was observed after administration of both forms. Apart from the C0 and C12, no significant differences in AUC0-12 h, tmax and Cmax of morphine between the rectal and oral route of administration were found. In the case of the metabolites, it was found that AUC0-12 h and Cmax of M6G, and AUC0-12 h, Cmax, C0 and C12 of M3G after rectal administration were significantly lower than after oral administration. However, apart from the tmax of M6G, none of the pharmacokinetic parameters of M, M6G or M3G met the criteria for bioequivalence. There were no significant (P = 0.44) differences in pain intensity score between the oral and rectal forms within the two groups, regardless of the treatment sequence. No treatment differences in nausea, sedation or the demand on escape medication (acetaminophen tablets) between the rectal and oral forms were observed.. The newly developed controlled-release M suppository is safe and effective and may be a useful alternative for oral morphine administration in patients with cancer pain.

Topics: Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Biological Availability; Cross-Over Studies; Double-Blind Method; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain, Intractable; Suppositories

To investigate the effect of acute P-glycoprotein inhibition by the multidrug-resistance (MDR) modulator valspodar (SDZ PSC 833; PSC) on the pharmacokinetics, and potentially adverse pharmacodynamic effects of morphine, and its principal pharmacologically active metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G).. In a double-blind, three-way crossover study, the pharmacokinetic and potentially adverse pharmacodynamic effects (reaction time, transcutaneous PCO2, blood pressure) of morphine were compared with and without acute inhibition of P-glycoprotein by PSC. The effects of PSC alone were also evaluated. The study was performed in 18 healthy male volunteers and pharmacodynamic effects analysed by measuring the area under the effect (AUE) curve. 150 mg PSC (or its placebo) was given as an i.v. infusion over 2 h. With the expected inhibition of Pgp 1 h after starting PSC infusion, 7.5 morphine HCl (or its placebo) was infused over 2 h.. The infusion of PSC resulted in blood concentrations expected to inhibit Pgp mediated transport. While the pharmacokinetics of plasma morphine and M6G. were unaffected there was a small but statistically significant increase in the AUC and Cmax of M3G (11.8 and 8.3%, respectively). The t(1/2) and tmax were unaffected. The pharmacokinetic parameters of PSC were not affected by coadministration with morphine. PSC did not significantly affect the adverse events of morphine, as assessed by spontaneous reporting. Compared with PSC alone, morphine elicited an increase in reaction time (Emax 48 ms, compared with the predose absolute reaction time of 644 ms), which was not detected by the alertness-drowsiness score, indicating only slight sedation. There was a significant decrease in systolic blood pressure (Emin -9 mm Hg), and a trend for a fall in diastolic blood pressure (Emin -14.5 mm Hg) and respiratory rate (Emin -1.8 breath x min(-1)). For all these parameters, the effects of PSC/morphine were similar to that of PSC alone, suggesting some attenuation of morphine's effect. In contrast, morphine caused a significant increase in PCO2 (Emax 0.69 kPa) compared to PSC alone, indicating slight respiratory depression. This increase was similar to that of the PSC/morphine combination.. Acute inhibition of P-glycoprotein by PSC in this setting does not affect the pharmacokinetic or safety-related pharmacodynamic profile of morphine in a clinically significant manner.

Topics: Adult; Analgesics, Opioid; Area Under Curve; ATP Binding Cassette Transporter, Subfamily B; Blood Gas Monitoring, Transcutaneous; Cross-Over Studies; Cyclosporins; Double-Blind Method; Drug Interactions; Half-Life; Humans; Injections, Intravenous; Male; Morphine; Morphine Derivatives; Reaction Time; Sleep Stages

We sought to provide a rational basis for morphine administration in preterm infants in the immediate postnatal period by determining the clearance and evaluating the efficacy and adverse effects of a continuous infusion.. Morphine was infused for 2 to 4 days (140 microg/kg over 1 hour followed by 20 microg/kg/h) to 31 ventilator-treated newborn infants (gestational age, 24 to 41 weeks; birth weight, 765 to 4,015 g). Morphine, morphine-3-glucuronide, and morphine-6-glucuronide concentrations in serum were determined from arterial blood obtained at 2, 12, 24, 48, and 60 hours after the start of morphine infusion at a median postnatal age of 10 hours.. The mean +/- SD steady-state morphine concentration, 167 +/- 77 ng/mL, was achieved between 24 and 48 hours of infusion, and morphine-6-glucuronide and morphine-3-glucuronide concentrations did not reach steady state within 60 hours. Morphine clearance (range, 0.8 to 6.5 mL/min/kg) correlated significantly with gestational age (r = 0.60; P < .01) and birth weight (r = 0.55; P < .01). Pain relief did not correlate with the steady-state morphine concentration. However, significantly higher morphine concentrations were found in infants with decreased gastrointestinal motility (187 +/- 82 ng/mL) compared with those without (128 +/- 51 ng/mL; P < .05).. Morphine should be used with caution in prematurely born infants because of its low clearance, which correlates with gestational age.

Topics: Birth Weight; Gestational Age; Humans; Infant, Newborn; Metabolic Clearance Rate; Morphine; Morphine Derivatives; Narcotics

Intrathecal administration of morphine produces intense analgesia, but it depresses respiration, an effect that can be life-threatening. Whether intrathecal morphine affects the ventilatory response to hypoxia, however, is not known.. We randomly assigned 30 men to receive one of three study treatments in a double-blind fashion: intravenous morphine (0.14 mg per kilogram of body weight) with intrathecal placebo; intrathecal morphine (0.3 mg) with intravenous placebo; or intravenous and intrathecal placebo. The selected doses of intravenous and intrathecal morphine produce similar degrees of analgesia. The ventilatory response to hypercapnia, the subsequent response to acute hypoxia during hypercapnic breathing (targeted end-tidal partial pressures of expired oxygen and carbon dioxide, 45 mm Hg), and the plasma levels of morphine and morphine metabolites were measured at base line (before drug administration) and 1, 2, 4, 6, 8, 10, and 12 hours after drug administration.. At base line, the mean (+/-SD) values for the ventilatory response to hypoxia (calculated as the difference between the minute ventilation during the second full minute of hypoxia and the fifth minute of hypercapnic ventilation) were similar in the three groups: 38.3+/-23.2 liters per minute in the placebo group, 33.5+/-16.4 liters per minute in the intravenous-morphine group, and 30.2+/-11.6 liters per minute in the intrathecal-morphine group (P=0.61). The overall ventilatory response to hypoxia (the area under the curve) was significantly lower after either intravenous morphine (20.2+/-10.8 liters per minute) or intrathecal morphine (14.5+/-6.4 liters per minute) than after placebo (36.8+/-19.2 liters per minute) (P=O.003). Twelve hours after treatment, the ventilatory response to hypoxia in the intrathecal-morphine group (19.9+/-8.9 liters per minute), but not in the intravenous-morphine group (30+/-15.8 liters per minute), remained significantly depressed as compared with the response in the placebo group (40.9+/-19.0 liters per minute) (P= 0.02 for intrathecal morphine vs. placebo). Plasma concentrations of morphine and morphine metabolites either were not detectable after intrathecal morphine or were much lower after intrathecal morphine than after intravenous morphine.. Depression of the ventilatory response to hypoxia after the administration of intrathecal morphine is similar in magnitude to, but longer-lasting than, that after the administration of an equianalgesic dose of intravenous morphine.

Topics: Adolescent; Adult; Analgesics, Opioid; Area Under Curve; Double-Blind Method; Humans; Hypercapnia; Hypoxia; Infusions, Intravenous; Injections, Spinal; Male; Middle Aged; Morphine; Morphine Derivatives; Respiration

Morphine-6-glucuronide (M6G) is an active metabolite of morphine with potent analgesic activity. Morphine-3-glucuronide (M3G), the most prevalent metabolite, has minimal affinity for opioid receptors. It has been suggested from animal model data and by examination of metabolite ratios in humans that M3G may functionally antagonize the respiratory depressant and analgesic actions of morphine and M6G.. We performed a double-blind placebo-controlled trial with 10 healthy volunteers. The trial had 6 arms: (1) placebo, (2) 10 mg/70 kg of morphine, (3) 3.3 mg/70 kg of M6G, (4) 30.6 mg/70 kg of M3G, (5) 30.6 mg/70 kg of M3G with 10 mg/70 kg of morphine, and (6) 30.6 mg/70 kg of M3G with 3.3 mg/70 kg of M6G; all were give by slow intravenous bolus. Analgesia was assessed with the use of the submaximal ischemic pain model. The effects were quantified on numerical and visual analogue scales. Respiratory parameters and response to steady state 5% carbon dioxide challenge were assessed with spirometry, mass spectroscopy, and earlobe blood gas analysis.. Morphine and M6G produced significant pain relief compared with placebo (morphine, P < .0001; M6G, P = .033). Pain relief after M6G was less than after morphine (P = .009) and M3G was no better than placebo (P = .26). Pain relief with morphine and M6G were not significantly altered by M3G (P = .59 and P = .28, respectively). Significant and similar dysphoria and sedation occurred with both morphine (P < .002) and M6G (P < .016) but were absent with both M3G and placebo. Respiratory parameters suggested that M6G produced less respiratory depression than morphine. Both morphine and M6G caused a significant reduction in respiratory drive compared with placebo (morphine, P = .002; M6G, P = .013); this effect was not reversed by M3G (P = .35 and P = .83, respectively).. M3G appears to be devoid of significant activity; in these circumstances and at these doses, it does not antagonize either the analgesic or respiratory depressant effects of M6G or morphine.

Topics: Adult; Analgesics, Opioid; Conscious Sedation; Cross-Over Studies; Double-Blind Method; Drug Interactions; Female; Humans; Male; Morphine; Morphine Derivatives; Pain; Pain Measurement; Placebos; Pulmonary Ventilation

1. In humans morphine is metabolised to morphine-3-glucuronide (M3G) which possess no opioid activity, and morphine-6-glucuronide (M6G) which is a potent opioid receptor agonist that probably contribute to the desired as well as toxic effects of morphine. 2. In order to investigate the possible effect of ranitidine on morphine glucuronidation indicated by clinical studies and later confirmed in vitro, a double blind cross-over study on eight human volunteers administered oral morphine plus ranitidine or placebo was conducted. 3. Urine was collected in fractions for 24 h. Serum and urine samples were prepared by solid phase extraction and morphine, M3G and M6G were quantified by HPLC. 4. Ranitidine significantly reduced the individual serum M3G/M6G ratio, and tended to increase the serum AUC(0-90) of morphine. In contrast, ranitidine had no significant effect on the urinary M3G/M6G ratio. The urinary recovery of morphine or morphine glucuronides was unaffected by ranitidine. 5 Possible explanations to the apparent incongruity between the serum and urine data are discussed.

Topics: Administration, Oral; Adult; Analgesics, Opioid; Area Under Curve; Chromatography, High Pressure Liquid; Cross-Over Studies; Double-Blind Method; Drug Interactions; Glucuronates; Histamine H2 Antagonists; Humans; Male; Morphine; Morphine Derivatives; Ranitidine

Methadone withdrawal symptoms have been reported in drug addicts treated with the tuberculostatic rifampin. Whereas this interaction can be explained by induction of phase I drug metabolism (CYP3A4), knowledge about induction of phase II metabolism (e.g., UDP-glucuronosyltransferases = UGTs) and its influence on drug effects in man, however, is very limited. The potent analgesic morphine is metabolized by more than one UGT to the active metabolite morphine-6-glucuronide and to morphine-3-glucuronide, which is devoid of analgesic activity. Thus, differential induction of UGTs involved in metabolism of morphine might lead to decreased or increased analgesic effects, depending on which UGT is preferentially induced. We therefore investigated the influence of the potent enzyme inducer rifampin on analgesic effects and pharmacokinetics of morphine, which is primarily eliminated by phase II metabolism. Ten healthy male volunteers participated in this double-blind, placebo-controlled study with double crossover design. Morphine (10 mg p.o.) and placebo were administered on two separate occasions before and near the end of 13 days of treatment with rifampin (600 mg/day). Blood samples were collected for 31 h. Morphine effects on pain sensation were determined using the cold pressor test. When morphine was given alone, the opioid elicited a significant increase in pain threshold and pain tolerance in comparison to placebo (P < or = 0.05). However, following administration of rifampin no analgesic effect of morphine was observed. In agreement, the area under the serum concentration-time curve (AUC) of morphine and the maximum serum concentration of morphine were considerably reduced during coadministration of rifampin (-27.7 +/- 19.3% and -40.7 +/- 27.1%; P < or = 0.01). Moreover, during treatment with rifampin a proportional reduction of AUCs of morphine-3-glucuronide (P < or = 0.01), morphine-6-glucuronide (P < or = 0.05) and morphine was observed. Since urinary recoveries of both morphine-3-glucuronide and morphine-6-glucuronide were also reduced during administration of rifampin, there is no evidence for a contribution of UGT induction to the observed interaction. In summary, a major drug interaction was observed between morphine and rifampin, which could not be attributed to induction of UGTs, but resulted in a complete loss of analgesic effects of the opioid.

Topics: Adult; Analgesics, Opioid; Antibiotics, Antitubercular; Cross-Over Studies; Double-Blind Method; Drug Therapy, Combination; Enzyme Induction; Humans; Male; Morphine; Morphine Derivatives; Rifampin

Plasma morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) concentrations were quantified by high performance liquid chromatography (HPLC) in 36 hospice inpatients receiving morphine orally or subcutaneously. The data were analyzed in relation to dose, serum creatinine, serum gamma glutamyl transferase, and presence or absence of opioid-induced adverse effects. There were significant associations (P < 0.05) between plasma morphine, M3G (subcutaneous route only), and M6G concentrations and dose for both routes of administration. The mean dose-corrected plasma morphine concentration for the subcutaneous group was three times that of the oral group, confirming present oral to subcutaneous dose conversion practices. Nineteen patients experienced symptoms attributed to morphine: nausea and vomiting in ten and acute delirium in nine. Serum creatinine was elevated in patients with adverse effects (P = 0.031), as were the dose-corrected plasma M3G (P = 0.029) and M6G (P = 0.043) concentrations. All seven patients with serum creatinine concentrations above the normal range had symptoms attributed to opioid-induced adverse effects. Plasma M3G, M6G, and dose-corrected plasma M3G and M6G concentrations were significantly (P < 0.001) higher in these patients than in those with normal serum creatinine concentrations. The data indicate that accumulation of M3G and M6G may be a causal or aggravating factor in the nausea and vomiting and cognitive function profile of palliative and terminal care patients with significant renal function impairment.

Topics: Adult; Aged; Female; Hospices; Humans; Male; Middle Aged; Morphine; Morphine Derivatives

Eleven morphine naïve patients with cancer-related pain were given a single dose of either intravenous morphine (n = 5) or oral morphine (n = 6). Blood sampling was performed over a 24-hr period and serial pain assessments were made using a categorical scale. Plasma samples were analyzed for morphine, morphine-6-glucuronide (M-6-G), morphine-3-glucuronide (M-3-G), and normorphine using high-performance liquid chromatography. In neither the intravenous nor oral group was there a correlation between analgesia duration and the half-lives of morphine and M-6-G. There was no correlation between the time to peak analgesia and time to peak concentration for morphine or M-6-G. There was no significant difference in absolute concentrations of M-6-G or M-3-6 nor in the ratio of M-3-G to M-6-G at peak analgesia versus relapse.

Topics: Administration, Oral; Analgesics, Opioid; Area Under Curve; Chromatography, High Pressure Liquid; Half-Life; Humans; Injections, Intravenous; Morphine; Morphine Derivatives; Neoplasms; Pain; Pain Measurement

There is limited knowledge about the pharmacokinetics of morphine and its metabolites after rectal administration in children. In this study the pharmacokinetics of two different rectal formulations of morphine were examined and compared with intravenous morphine.. Children undergoing elective surgery received rectal morphine 0.2 mg/kg before start of surgery. Ten children (mean age 14 months) received morphine rectally in a hydrogel formulation and another 10 children (mean age 16 months) received morphine rectally in a parenteral formulation. For comparison, 6 children (mean age 21 months) were given the same dose intravenously. The plasma concentrations of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were measured by HPLC over 6 h after drug administration.. The mean rectal bioavailability of morphine was 35% (range 18-59) after hydrogel administration and 27% (range 6-93) after the solution. Mean values of Cmax were 76 nmol/l (25-129) and 56 nmol/1 (15-140), respectively. The results showed that morphine gel had a significantly higher bioavailability (P < 0.02) than the solution. The ratios of plasma (M3G + M6G) to morphine were higher after rectal administration (mean 7.5-8.7) than after i.v. injection (mean 5.3), indicating the presence of first-pass metabolism using the rectal route.. The rectal morphine hydrogel has pharmacokinetic properties which makes it a useful formulation for premedication and pain alleviation in paediatric patients.

Topics: Administration, Rectal; Analgesics, Opioid; Child, Preschool; Humans; Infant; Morphine; Morphine Derivatives

1. The pharmacokinetics of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) were studied in 19 ventilated newborn infants (24-41 weeks gestation) who were given a loading dose of 50 micrograms kg-1 or 200 micrograms kg-1 of diamorphine followed by an intravenous infusion of 15 micrograms kg-1 h-1 of diamorphine. Plasma concentrations of morphine, M3G and M6G were measured during the accrual to steady-state and at steady state of the diamorphine infusion. 2. Following both the 50 micrograms kg-1 or 200 micrograms kg-1 loading doses the mean steady-state plasma concentration (+/- s.d.) of morphine, M3G and M6G were 86 +/- 52 ng ml-1, 703 +/- 400 ng ml-1 and 48 +/- 28 ng ml-1 respectively and morphine clearance was found to be 4.6 +/- 3.2 ml min-1 kg-1. 3. M3G formation clearance was estimated to be 2.5 +/- 1.8 ml min-1 kg-1, and the formation clearance of M6G was estimated to be 0.46 +/- 0.32 ml min-1 kg-1. 4. M3G metabolite clearance was 0.46 +/- 0.60 ml min-1 kg-1, the elimination half-life was 11.1 +/- 11.3 h and the volume of distribution was 0.55 +/- 1.13 l kg-1. M6G metabolite clearance was 0.71 +/- 0.36 ml min-1 kg-1, the elimination half-life was 18.2 +/- 13.6 h and the volume of distribution was 1.03 +/- 0.88 l kg-1. 5. No significant effect of the loading dose (50 micrograms kg-1 or 200 micrograms kg-1) on the plasma morphine or metabolite concentrations or their derived pharmacokinetic parameters was found. 6. We were unable to identify correlations between gestational age of the infants and any of the determined pharmacokinetic parameters. 7. M3G: morphine and M6G: morphine steady-state plasma concentration ratios were 11.0 +/- 10.8 and 0.8 +/- 0.8, respectively. 8. The metabolism of morphine in neonates, in terms of the respective contributions of each glucuronide pathway, was similar to that in adults.

Topics: Analgesics, Opioid; Half-Life; Heroin; Humans; Infant, Newborn; Infant, Premature; Infusions, Intravenous; Morphine; Morphine Derivatives

Ten patients who suffered from severe cancer-related pain participated in a randomised, double-blind and cross-over study to compare the effectiveness and acceptability of epidural and subcutaneous administration of morphine. The patients titrated themselves pain-free in 48 h using a patient controlled analgesia system. The median daily doses calculated from the consumption of the last 4-h study period were 372 mg for subcutaneous and 106 mg for epidural administration. The two modes of morphine administration turned out to be comparable in terms of both effectiveness and acceptability. Both treatments provided better pain relief with less adverse effects compared with the prestudy oral morphine treatment.

Topics: Adult; Aged; Analgesia, Patient-Controlled; Analgesics, Opioid; Blood Chemical Analysis; Cross-Over Studies; Double-Blind Method; Evaluation Studies as Topic; Female; Humans; Injections, Epidural; Injections, Subcutaneous; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Palliative Care

Plasma and cerebrospinal fluid (CSF) steady-state concentrations (Css) of morphine (M) and the main metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), were determined by high performance liquid chromatography (HPLC) in 21 cancer patients treated with chronic subcutaneous morphine infusion. There was a moderate, but statistically significant correlation between the daily dose of morphine and the concentrations of morphine, M3G and M6G in CSF. A poorer correlation to concentrations were seen in plasma. The mean +/- SEM CSF/plasma morphine concentration ratio was 0.36 +/- 0.07. In plasma and CSF, the mean steady state concentration of M3G but not M6G substantially exceeded that of morphine where the mean CSF M/M3G/M6G ratio was 1:15:0.5 (molar basis), and the mean plasma ratio was M/M3G/M6G 1:31:3 (molar basis). The mean M3G and M6G concentrations in CSF were approximately 8 and 10% of those found in plasma, but there was a wide interindividual variation. Plasma concentrations of both morphine glucuronides were positively correlated to serum creatinine. Neither pain intensity, evaluated by visual analogue scale (VAS), nor side effects showed any relationship to the CSF M3G concentrations, M3G/M or the M3G/M6G ratios. We conclude that during steady state subcutaneous administration of morphine, there is a large interindividual variation in plasma morphine with poor relationship to the daily administered dose. In CSF this correlation was more evident. Plasma and CSF concentrations of M3G and CSF concentrations of M6G correlated with administered morphine dose. There was an accumulation of both morphine glucuronides in patients with elevated serum creatinine. Measurements of morphine, M3G and M6G in CSF did not show any overt relationship to analgesia or side effects.

Topics: Aged; Aged, 80 and over; Analgesics, Opioid; Creatinine; Dose-Response Relationship, Drug; Female; Humans; Infusions, Parenteral; Kidney Function Tests; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain

The kinetics of 20 mg nicomorphine intramuscularly were described in 8 patients under combined general and epidural anesthesia. The half-life of nicomorphine was 0.32 +/- 0.20 h (mean +/- SD) and is governed by the absorption-rather than the elimination rate. The half-life of 6-mononicotinoylmorphine (0.39 +/- 0.09 h) was identical to that of the parent compound (p = 0.29), suggesting it is directly related to the absorption rate of nicomorphine. Morphine had a half-life of 1.38 +/- 0.31 h. Morphine is subsequently metabolized into morphine-3-glucuronide and morphine-6-glucuronide. The half-life of these 2 glucuronide conjugates was about 2.6 h (p = 0.07). A glucuronide conjugate of 6-mononicotinoylmorphine was not detected. In urine only morphine and its glucuronides are found, with renal clearance values of 214 ml.min-1 for morphine and 132 ml.min-1 for the glucuronides. The bioavailability of this pharmaceutical formulation after intramuscular administration equals that of intravenous administration in surgical patients (at the same dose).

Topics: Adult; Biological Availability; Calibration; Chromatography, High Pressure Liquid; Female; Half-Life; Humans; Injections, Intramuscular; Middle Aged; Morphine; Morphine Derivatives; Nicotinic Acids; Reproducibility of Results

The management and treatment of chronic pain in cancer patients is a clear priority for practitioners regularly confronted by the situation. This investigation was carried out to evaluate the bioavailability of a recent sustained-release (SR) formulation of morphine sulphate (30 mg), Skenan, consisted of capsules, relative to a recognized product, Moscontin which is a matrix tablet SR form. The bioavailability was carried out on 12 healthy male volunteers who received a single dose (30 mg) of the test (T) and the recognized (R) products in a randomized balanced 2-way crossover design. After dosing, serial blood samples were collected for a period of 24 hours. Morphine and its main metabolites (i.e. glucuronides M6G and M3G) were assayed by high-performance liquid chromatography using a ion-pair formation. Data were analyzed by a noncompartmental method and were compared by ANOVA method and, each subject taken as his own control, by the Wilcoxon T test. Mean bioavailability of the T formulation was greater than that of R. The parametric confidence intervals (90%) of the mean values of the pharmacokinetics characteristics for T:R ratio were in each case without the bioequivalence acceptable ranges of 0.8-1.25 and 0.70-1.43 respectively for AUCs (i.e. AUCo-->24h and AUCo-->infinity) and Cmax, while confidence intervals symmetric of Westlake (CIW90%) was invariably greater than 20%, i.e. 62.8, 71.1 and 39.3% respectively. Further, the test formulation was not found bioequivalent to the reference formulation by Schuirmann's 2 one-sided t-test. These results justify the conclusion of the non-bioequivalence of the two forms at the unit dose of 30 mg. This information must be considered above all as a dosage adjustment tool enabling use of the two forms by application of a correction factor of the order of 15% when prescribing Skenan in comparison with Moscontin. Assessment is needed of the possible clinical consequences of this finding.

Topics: Adult; Analgesics, Opioid; Cross-Over Studies; Delayed-Action Preparations; Humans; Male; Morphine; Morphine Derivatives; Therapeutic Equivalency

Concentrations of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were measured by h.p.l.c. in plasma and cerebrospinal fluid (CSF) samples from 16 patients with cancer receiving oral (controlled-release) morphine. There was a close correlation between plasma and CSF morphine concentrations (r = 0.94, P = 0.0001) and both correlated with drug dosage (r = 0.61, P = 0.013 and r = 0.74, P = 0.0001, respectively). M3G and M6G in plasma and CSF were correlated (r = 0.81 and r = 0.82, both P = 0.0001). No relationship was apparent between M plus M6G concentrations in the CSF and pain scores.

Topics: Administration, Oral; Adult; Aged; Chromatography, High Pressure Liquid; Delayed-Action Preparations; Dose-Response Relationship, Drug; Female; Humans; Linear Models; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Pain Measurement

Morphine-6-glucuronide is a metabolite of morphine that shows significant analgesic effects in animals and humans. To evaluate route-specific differences in the potential contribution of morphine-6-glucuronide to morphine analgesia, we studied the pharmacokinetics of morphine, morphine-6-glucuronide, and morphine-3-glucuronide after oral and rectal administration of morphine sulfate in a six-subject randomized, single-dose, two-way crossover evaluation. The mean area under the plasma concentration-time curve (AUC) molar ratios of morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) to morphine (M) were greater after oral morphine administration compared with rectal morphine administration (M6G/M ratio, 2.7:1 versus 1.3:1, p = 0.025; M3G/M ratio, 18.3:1 versus 9.3:1, p = 0.002). Systemic bioavailability and peak plasma concentrations of morphine-6-glucuronide and morphine-3-glucuronide were significantly greater after oral morphine administration compared with the rectal route (AUC: M6G, 377.1 +/- 124.2 versus 236.2 +/- 133.7 nmol.hr/L, p = 0.05; M3G, 2610.1 +/- 446.4 versus 1650.2 +/- 309.0 nmol.hr/L, p = 0.004; maximum concentrations: M6G, 110.9 +/- 37.5 versus 64.6 +/- 28.8 nmol/L, p = 0.002; M3G, 576.9 +/- 155.8 versus 266.8 +/- 110.5 nmol/L, p = 0.007). Conversely, the systemic availability of morphine was lower after oral administration, although this difference failed to achieve statistical significance (142.3 +/- 17.1 versus 176.6 +/- 69.4 nmol.hr/L, p = 0.14). These data suggest that rectal administration of morphine is associated with significant avoidance of hepatic biotransformation, and they provide a convincing argument for the evaluation of morphine-6-glucuronide concentrations in pharmacokinetic and pharmacodynamic comparisons involving different routes of morphine administration.

Topics: Administration, Oral; Administration, Rectal; Adult; Biological Availability; Humans; Male; Morphine; Morphine Derivatives

Sustained-release morphine (MST) given by the rectal route was compared with oral MST in an open randomised cross-over trial in ten patients with cancer who received stable doses of MST. No significant difference was found in the areas under the curve of the concentration-time profiles (AUC) following oral or rectal administration for parent morphine. The AUCs determined for morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) after oral administration were approximately twice those obtained following rectal administration. The maximal concentration achieved was lower and the time to maximal concentration was longer following rectal administration for morphine, M6G and M3G. The relative mean arrival times following rectal administration were significantly longer for morphine and M3G but not for M6G. These findings suggest slower absorption but less first-pass metabolism of MST after rectal administration. No significant difference was noted between the oral and the rectal route in measurements on visual-analogue scales for pain or side effects. We recommend the rectal route as being suitable for MST administration when the oral route is no longer available. In changing from oral to rectal administration, the same dose and dose interval may be used, but dose adjustment may be needed.

Topics: Administration, Oral; Administration, Rectal; Adult; Aged; Aged, 80 and over; Delayed-Action Preparations; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Pain Measurement; Time Factors

The single-dose and steady state kinetics of morphine given as controlled-release tablets (30 mg every 12 h) and as a solution (15 mg every 6 h) have been compared in 11 cancer patients with chronic pain. The concentrations of morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) were analyzed by HPLC. There were no significant differences between the tablets and solution in the mean steady state concentrations of morphine, M3G or M6G. The tmax was 3.3 h for the tablets compared to 1.1 h for the solution. After giving the controlled-release tablets every 12 h there was a significantly higher fluctuation index of the morphine concentrations than after the solution. Urinary recovery at steady state was comparable between the two preparations, with averages of 57% and 47%, respectively. Thus, no major differences were found in the pharmacokinetics of morphine and its glucuronidated metabolites after 30 mg morphine as controlled-release tablets every 12 h or 15 mg of morphine solution every 6 h, except for a significantly longer tmax and greater fluctuation in morphine concentrations after the controlled-release tablets.

Topics: Adenocarcinoma; Administration, Oral; Aged; Carcinoma, Small Cell; Carcinoma, Squamous Cell; Delayed-Action Preparations; Female; Half-Life; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Solutions; Tablets

Differences in the patterns of urinary morphine metabolites were determined in 15 patients after the prolonged administration of morphine via various routes (oral, subcutaneous, intravenous). The possible correlation between metabolite pattern and the route of prolonged morphine administration was investigated. It was established that the concentration ratios of the active metabolite, morphine-6-glucuronide to morphine and its inactive metabolite, morphine-3-glucuronide are significantly (p less than 0.05) higher after prolonged oral morphine treatment than after the systemic administration (subcutaneous or intravenous infusion) of morphine. It may therefore be concluded that patients receiving morphine orally produced significantly greater amounts of its pharmacologically more active metabolite than patients subjected to chronic systemic morphine treatment.

Topics: Administration, Oral; Biotransformation; Humans; Infusions, Intravenous; Morphine; Morphine Derivatives; Pain, Postoperative; Retrospective Studies; Time Factors

The pharmacokinetics of morphine administered via the buccal route as a controlled release formulation were assessed after the administration of three different doses and found to be linear in the dose range 10-30 mg. The plasma concentrations of morphine-3-glucuronide and morphine-6-glucuronide demonstrated considerable inter-subject variation and conclusions could not be drawn regarding their pharmacokinetics. These large differences may reflect not only variability in buccal absorption, but may have resulted from the preparation dissolving in saliva, followed by absorption from the gastrointestinal tract.

Topics: Absorption; Administration, Buccal; Aged; Humans; Middle Aged; Morphine; Morphine Derivatives

Intravenous (i.v.) morphine is a safe, robust, and recommended treatment for severe pain using the titration principle. Despite its high efficacy, it is impacted by organizational constraints related to venous access. Nebulized (NEB) morphine may represent an alternative for titration but pharmacokinetic (PK) properties of short nebulization using routine devices need evaluation. Twenty-seven healthy volunteers were included to receive NEB or i.v. morphine administration using increasing amounts according to Dixon's reference method. Plasma morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) were quantified. PK modeling and simulations were performed using Monolix. Dixon's method exhibited a significantly higher morphine dose regimen in the NEB group versus the i.v. group (6.2 [5.3-7.1] vs. 3.0 [2.0-4.0] mg, p < 0.001). Morphine, M3G, and M6G dose-normalized exposure were significantly lower in the NEB group versus the i.v. group: morphine (19 [13-23] vs. 1044 [702-1266] µg min/L, p < 0.001), M3G (245 [162-287] vs. 3752 [2487-5165] µg min/L, p < 0.001) and M6G (28 [21-43] vs. 466 [370-723] µg min/L, p < 0.001). The model that best fitted the data consisted in a transit compartment for morphine absorption, three compartments for morphine distribution followed by multiple transit compartments (8.2 and 57.5-min transit time for M3G and M6G, respectively) and a first order elimination for M3G and M6G. Morphine bioavailability in the NEB group was 3.5% using the i.v. group as reference. Administration route and sex significantly influenced morphine and metabolite PKs. This work aimed to evaluate the PKs of NEB morphine compared with the i.v. route. Despite a bioavailability to improve, NEB morphine administration using a routine device is suitable to plan morphine titration.

Topics: Administration, Inhalation; Adult; Analgesics, Opioid; Computer Simulation; Dose-Response Relationship, Drug; Female; Healthy Volunteers; Humans; Injections, Intravenous; Male; Middle Aged; Models, Biological; Morphine; Morphine Derivatives; Nebulizers and Vaporizers; Sex Factors

Tolerance and hyperalgesia associated with chronic exposure to morphine are major limitations in the clinical management of chronic pain. At a cellular level, neuronal signaling can in part account for these undesired side effects, but unknown mechanisms mediated by central nervous system glial cells are likely also involved. Here we applied data-independent acquisition mass spectrometry to perform a deep proteome and phosphoproteome analysis of how human astrocytes responds to opioid stimulation. We unveil time- and dose-dependent effects induced by morphine and its major active metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide that converging on activation of mitogen-activated protein kinase and mammalian target of rapamycin signaling pathways. We also find that especially longer exposure to M3G leads to significant dysregulation of biological pathways linked to extracellular matrix organization, antigen presentation, cell adhesion, and glutamate homeostasis, which are crucial for neuron- and leukocyte-astrocyte interactions.

Topics: Astrocytes; Humans; Morphine; Morphine Derivatives; Proteomics

In humans, the drug metabolizing enzyme CYP2D6 is highly polymorphic resulting in substantial differences in the metabolism of drugs including anti-arrhythmics, neuroleptics, and opioids. The objective of this study was to phenotype a population of 100 horses from five different breeds and assess differences in the metabolic activity of the equine CYP2D6 homolog using codeine as a probe drug. Administration of a probe drug is a common method used for patient phenotyping in human medicine, whereby the ratio of parent drug to metabolite (metabolic ratio, MR) can be used to compare relative enzyme function between individuals. A single oral dose of codeine (0.6 mg/kg) was administered and plasma concentrations of codeine and its metabolites were determined using liquid chromatography mass spectrometry. The MR of codeine O-demethylation [(codeine)/(morphine + morphine-3-glucuronide + morphine-6-glucuronide)] was determined using the area under the plasma concentration-time curve extrapolated from time zero to infinity (AUC. The MR of codeine O-demethylation ranged from 0.002 to 0.147 (median 0.018) among all horses. No significant difference in MR was observed between breeds, age, or sex. Of the 100 horses, 11 were classified as high-MR, 72 moderate-MR, and 17 low-MR. Codeine AUC. The MR calculated from plasma following codeine administration allowed for classification of horses into metabolic phenotypes within a large population. The range of codeine metabolism observed among horses suggests the presence of genetic polymorphisms in CYP2D82 of which codeine is a known substrate. Additional studies including CYP2D82 genotyping of high- and low-MR individuals are necessary to determine the presence of CYP2D polymorphisms and their functional implications with respect to the metabolism of therapeutics.

Topics: Animals; Codeine; Cytochrome P-450 CYP2D6; Female; Horses; Male; Morphine Derivatives; Phenotype; Polymorphism, Genetic

The USA and numerous other countries worldwide are currently experiencing a public health crisis due to the abuse of heroin and illicitly manufactured fentanyl. We have developed a liquid chromatography tandem mass spectrometry (LC-MS-MS)-based method for the detection of morphine, fentanyl and their metabolites, including morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G), normorphine, norfentanyl and deuterated internal standards in limited sample volumes with the limit of detection of 5.0/0.5 ng/mL (morphine, M3G, M6G, normorphine/fentanyl, norfentanyl). The inter-assay precision (%CV) was less than 12% for all assays, and the inter-assay bias (%) was less than 5%. The ruggedness of the method, dilution effect and carryover were also investigated as part of the study. The simultaneous quantification of morphine, fentanyl and its metabolites via this simple and time- and cost-efficient method could be successfully applied to samples taken for pharmacokinetic evaluation (antemortem and postmortem) after a single dose of morphine or co-administration of morphine with other drugs (e.g., fentanyl) in rats.

Topics: Animals; Chromatography, Liquid; Fentanyl; Heroin; Morphine; Morphine Derivatives; Rats; Reproducibility of Results; Substance Abuse Detection; Tandem Mass Spectrometry

Epidural administration of morphine has been shown to be an effective analgesic strategy in horses; however, the possible occurrence of side effects limits its usage. In order to decrease their frequency, it is important to target the minimal effective plasma concentration and avoid overdosing. As to date species-specific pharmacokinetics data are not available for epidural morphine, the dosing regimen is usually established on the basis of clinical reports and personal experience. In certain physiological conditions, like gestation, the outcome of an empirical dosing scheme can be unpredictable. The aim of this case report is to describe the pharmacological profile of morphine and its metabolites after prolonged epidural administration in a pregnant mare and her foal.. A 20 years old pregnant mare was presented to our hospital because of severe lameness, 2 months before delivery. Following an ineffective systemic pain treatment, an epidural catheter was inserted and morphine administered (initial dose 0.1 mg/kg every 8 h). Due to its efficacy in controlling pain, it was continued until end of gestation. Plasmatic concentration of morphine and its metabolites were assessed in the mare 6 weeks after starting the treatment, and in both the mare and foal during the first days after delivery. Plasmatic values similar to those previously reported in the literature following morphine short term administration through various routes and not accompanied by side effects were found in the mare, except during an excitatory period. Moreover, no evidence of dangerous drug accumulation or significant milk passage was noticed in the foal. Mild reduction of feces production with no signs of colic and two self-limiting episodes of excitement occurred during treatment in the mare. No side effects occurred during gestation and first phases of life in the foal.. Prolonged epidural administration of morphine in a pregnant mare allowed good pain control in absence of clinically relevant side effects, in both the mare and her foal. Sudden increase in morphine plasmatic concentration can occur and side effects appear; careful treatment to the lowest effective dose and continuous monitoring of the clinical condition of the treated horse should be performed.

Topics: Analgesics, Opioid; Animals; Animals, Newborn; Female; Horses; Injections, Epidural; Lameness, Animal; Morphine; Morphine Derivatives; Pain; Pregnancy; Tendinopathy

Heroin abuse is a serious problem that endangers human health and affects social stability. Though often being used as confirmation of heroin use, 6-monoacetylmorphine (6-MAM) has limitations due to its short detection window. To compare the detection windows of heroin metabolites (morphine (MOR), 6-MAM, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G)) in human urine, an automated online solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated. The limits of detections (LODs) of the four metabolites were in the range of 1.25-5 ng/mL. Intra and inter-day precision for all the metabolites was 0.4-6.7% and 1.8-7.3%, respectively. Accuracy ranged from 92.9 to 101.7%. This method was then applied to the analysis of urine samples of 20 male heroin abusers. M3G was detected 9-11 days after admission to the drug rehabilitation institute in 40% of heroin users while MOR or M6G was not always detected. The detection window of M3G was thus the longest. Furthermore, M3G had a much higher concentration than MOR and M6G. Therefore, M3G could provide diagnostic information with regard to heroin exposure in the combination with other clues (e.g., heroin seizures at the scene).

Topics: Chromatography, High Pressure Liquid; Chromatography, Liquid; Heroin; Heroin Dependence; Humans; Limit of Detection; Morphine Derivatives; Solid Phase Extraction; Substance Abuse Detection; Tandem Mass Spectrometry

The objective of the current study was to describe and characterize the pharmacokinetics and selected pharmacodynamic effects of morphine and its two major metabolites in horses following several doses of morphine. A total of ten horses were administered a single intravenous dose of morphine: 0.05, 0.1, 0.2, or 0.5 mg/kg, or saline control. Blood samples were collected up to 72 hr, analyzed for morphine, and metabolites by LC/MS/MS, and pharmacokinetic parameters were determined. Step count, heart rate and rhythm, gastrointestinal borborygmi, fecal output, packed cell volume, and total protein were also assessed. Morphine-3 glucuronide (M3G) was the predominant metabolite detected, with concentrations exceeding those of morphine-6 glucuronide (M6G) at all time points. Maximal concentrations of M3G and M6G ranged from 55.1 to 504 and 6.2 to 28.4 ng/ml, respectively, across dose groups. The initial assessment of morphine pharmacokinetics was done using noncompartmental analysis (NCA). The volume of distribution at steady-state and systemic clearance ranged from 9.40 to 16.9 L/kg and 23.3 to 32.4 ml min

Topics: Analgesics, Opioid; Animals; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Horses; Injections, Intravenous; Male; Morphine; Morphine Derivatives

To develop a pharmacokinetic-pharmacogenomic population model of morphine in critically ill children with acute respiratory failure.. Prospective pharmacokinetic-pharmacogenomic observational study.. Thirteen PICUs across the United States.. Pediatric subjects (n = 66) mechanically ventilated for acute respiratory failure, weight greater than or equal to 7 kg, receiving morphine and/or midazolam continuous infusions.. Serial blood sampling for drug quantification and a single blood collection for genomic evaluation.. Concentrations of morphine, the two main metabolites, morphine-3-glucuronide and morphine-6-glucuronide, were quantified by high-performance liquid chromatography tandem mass spectrometry/mass spectroscopy. Subjects were genotyped using the Illumina HumanOmniExpress genome-wide single nucleotide polymorphism chip. Nonlinear mixed-effects modeling was performed to develop the pharmacokinetic-pharmacogenomic model. A two-compartment model with linear elimination and two individual compartments for metabolites best describe morphine disposition in this population. Our analysis demonstrates that body weight and postmenstrual age are relevant predictors of pharmacokinetic parameters of morphine and its metabolites. Furthermore, our research shows that a duration of mechanical ventilation greater than or equal to 10 days reduces metabolite formation and elimination upwards of 30%. However, due to the small sample size and relative heterogeneity of the population, no heritable factors associated with uridine diphosphate glucuronyl transferase 2B7 metabolism of morphine were identified.. The results provide a better understanding of the disposition of morphine and its metabolites in critically ill children with acute respiratory failure requiring mechanical ventilation due to nonheritable factors. It also provides the groundwork for developing additional studies to investigate the role of heritable factors.

Topics: Acute Disease; Adolescent; Age Factors; Analgesics, Opioid; Body Weight; Child; Child, Preschool; Critical Illness; Female; Genotype; Glucuronosyltransferase; Humans; Infant; Male; Morphine; Morphine Derivatives; Pharmacogenomic Testing; Prospective Studies; Respiration, Artificial; Respiratory Insufficiency; Time Factors

Current hair testing methods that rely solely on quantification of parent drug compounds are unable to definitively distinguish between drug use and external contamination. One possible solution to this problem is to confirm the presence of unique drug metabolites that cannot be present through contamination, such as phase II glucuronide conjugates. This work demonstrates for the first time that codeine-6-glucuronide, hydromorphone-3-glucuronide, oxymorphone-3-glucuronide, morphine-3-glucuronide and morphine-6-glucuronide are present at sufficient concentrations to be quantifiable in hair of opioid users and that their concentrations generally increase as the concentrations of the corresponding parent compounds increase. Here, we present a validated liquid chromatography tandem mass spectrometry method to quantify codeine-6-glucuronide, dihydrocodeine-6-glucuronide, hydromorphone-3-glucuronide, morphine-3-glucuronide, morphine-6-glucuronide, oxymorphone-3-glucuronide, codeine, dihydrocodeine, dihydromorphine, hydrocodone, hydromorphone, morphine, oxycodone, oxymorphone and 6-acetylmorphine in human hair. The method was used to analyze 46 human hair samples from known drug users that were confirmed positive for opioids by an independent laboratory. Glucuronide concentrations in samples positive for parent analytes ranged from ~1 to 25 pg/mg, and most samples had glucuronide concentrations in the range of ~1 to 5 pg/mg. Relative to the parent concentrations, the average concentrations of the four detected glucuronides were as follows: codeine-6-glucuronide, 2.33%; hydromorphone-3-glucuronide, 0.94%; oxymorphone-3-glucuronide, 0.77%; morphine 3-glucuronide, 0.59%; and morphine-6-glucuronide, 0.93%.

Topics: Chromatography, Liquid; Codeine; Glucuronates; Hair; Humans; Hydromorphone; Limit of Detection; Morphine Derivatives; Opioid-Related Disorders; Reproducibility of Results; Specimen Handling; Substance Abuse Detection; Tandem Mass Spectrometry

Preclinical studies report that the effective dose for morphine is approximately 2-fold higher in females than males. Following systemic administration, morphine is metabolized via Phase II glucuronidation in the liver and brain into two active metabolites: morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), each possessing distinct pharmacological profiles. M6G binds to μ opioid receptors and acts as a potent analgesic. In contrast, M3G binds to toll-like receptor 4 (TLR4), initiating a neuroinflammatory response that directly opposes the analgesic effects of morphine and M6G. M3G serum concentrations are 2-fold higher in females than males, however, sex-specific effects of morphine metabolites on analgesia and glial activation in vivo remain unknown. The present studies test the hypothesis that increased M3G, and subsequent TLR4-mediated activation of glia, is a primary mechanism driving the attenuated response to morphine in females. We demonstrate that intra-PAG M6G results in a greater analgesic response in females than morphine alone. M6G analgesia was reversed with co-administration of (-)-naloxone, but not (+)-naloxone, suggesting that this effect is μ opioid receptor mediated. In contrast, intra-PAG administration of M3G significantly attenuated the analgesic effects of systemic morphine in males only, increasing the 50% effective dose of morphine two-fold (5.0 vs 10.3mg/kg) and eliminating the previously observed sex difference. An increase in IL-1β, IL-6 and TNF was observed in females following intra-PAG morphine or M6G. In males, only IL-1β levels increased following morphine. Changes in cytokine levels following M3G were limited to TNF in females. Together, these data implicate sex differences in morphine metabolism, specifically M3G, as a contributing factor in the attenuated response to morphine observed in females.

Topics: Analgesics, Opioid; Animals; Cytokines; Dose-Response Relationship, Drug; Female; Male; Morphine; Morphine Derivatives; Naloxone; Narcotic Antagonists; Nociception; Pain Threshold; Periaqueductal Gray; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sex Characteristics; Time Factors; Toll-Like Receptor 4

In heroin-related deaths, it is often of interest to determine the approximate time span between intake of heroin and death, and to decide whether heroin or other opioids have been administered. In some autopsy cases, peripheral blood cannot be sampled due to decomposition, injuries or burns. The aim of the present study was to investigate whether measurements of heroin metabolites in matrices other than peripheral blood can be used to differentiate between rapid and delayed heroin deaths, and if morphine/codeine ratios measured in other matrices can separate heroin from codeine intakes.. In this study, we included 51 forensic autopsy cases where morphine was detected in peripheral blood. Samples were collected from peripheral and cardiac blood, pericardial fluid, psoas and lateral vastus muscles, vitreous humor and urine. The opioid analysis included 6-acetylmorphine (6-AM), morphine, morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G) and codeine. Urine was only used for qualitative detection of 6-AM. 45 heroin-intake cases were divided into rapid deaths (n=24), based on the detection of 6-AM in blood, or delayed deaths (n=21), where 6-AM was detected in at least one other matrix but not in blood. An additional 6 cases were classified as codeine-intake cases, based on a morphine/codeine ratio below unity (<1) in peripheral blood, without detecting 6-AM in any matrix.. The median morphine concentrations were significantly higher in the rapid compared with the delayed heroin deaths in all matrices (p=0.004 for vitreous humor and p<0.001 for the other matrices). In the rapid heroin deaths, the M3G/morphine concentration ratios were significantly lower than in the delayed deaths both in peripheral and cardiac blood (p<0.001), as well as in pericardial fluid (p<0.001) and vitreous humor (p=0.006), but not in muscle. The morphine/codeine ratios measured in cardiac blood, pericardial fluid and the two muscle samples resembled the ratios in peripheral blood, although codeine was less often detected in other matrices than peripheral blood.. Measurements of heroin-metabolites in cardiac blood, pericardial fluid and vitreous humor provide information comparable to that of peripheral blood regarding rapid and delayed heroin deaths, e.g. M3G/morphine ratios <2 indicate a rapid death while ratios >3 indicate a delayed death. However, considerable overlap in results from rapid and delayed deaths was observed, and measurements in muscle appeared less useful. Furthermore, matrices other than peripheral blood can be used to investigate morphine/codeine ratios, but vitreous humor seems less suited.

Topics: Codeine; Drug Overdose; Forensic Toxicology; Heroin; Heroin Dependence; Humans; Morphine; Morphine Derivatives; Muscle, Skeletal; Pericardial Fluid; Postmortem Changes; Time Factors; Vitreous Body

Uridine diphosphate-glucuronosyltransferase (UGT) 2B7, as one of significant drug enzymes, is responsible on the glucuronidation of abundant endobiotics or xenobiotics. We here report that it is markedly repressed in the tumor tissues of colorectal carcinoma (CRC) patients. Accordingly, morphine in CRC cells will stimulate the expression of its main metabolic enzyme, UGT2B7 during tolerance generation by activating the positive signals in histone 3, especially for trimethylated lysine 27 (H3K4Me3) and acetylated lysine 4 (H3K27Ac). Further study reveals that brain-derived neutrophilic factor (BDNF), a secretory neurotrophin, enriched in CRC can interact and inhibit UGT2B7 by primarily blocking the positive signals of H3K4Me3 as well as activating H3K27Ac on the promoter region of UGT2B7. Meanwhile, BDNF repression attributes to the sensitizations of main core factors in poly-comb repressive complex (PRC) 1 rather than PRC2 as the reason of the depression of SUZ12 in the later complex. Besides that, the productions of two main morphine glucuronides are both increased in the BDNF deficient or TSA and BIX-01294 treated morphine tolerance-like HCT-116 cells. On the same condition, active metabolite, morphine-6-glucuronide (M6G) was accumulated more than inactive M3G. Our findings imply that enzymatic activity enhancement and substrate regioselective catalysis alteration of UGT2B7 may release morphine tolerance under the cure of tumor-induced pain.

Topics: Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Azepines; Brain-Derived Neurotrophic Factor; Cancer Pain; Cell Line, Tumor; Colorectal Neoplasms; Drug Tolerance; Epigenetic Repression; Female; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Glucuronosyltransferase; Histocompatibility Antigens; Histone-Lysine N-Methyltransferase; Histones; Humans; Immunohistochemistry; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasm Proteins; Polycomb Repressive Complex 1; Polycomb Repressive Complex 2; Promoter Regions, Genetic; Quinazolines; RNA Interference; RNA, Small Interfering; Transcription Factors; Up-Regulation

Morphine is administered intravenously for pain management in the perioperative period. The effect of the inflammatory response to surgery on morphine distribution across the blood-brain barrier (BBB) in humans was investigated. We hypothesized that a graded surgically induced, systemic inflammatory response alters cerebrospinal fluid (CSF) levels of morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) through a temporary reduction in BBB drug efflux transporter function.. We conducted a prospective pharmacokinetic study of the plasma and CSF distribution of the P-glycoprotein (PGP) substrate morphine in 33 patients undergoing open thoracic (n = 18) or endovascular (n = 15) aortic aneurysm repair. Morphine was administered with induction of anesthesia and in the intensive care unit. Plasma and CSF concentrations of interleukin (IL)-6, morphine, M3G, M6G, and albumin were measured prior to surgery (baseline), during surgery, and postoperatively every six hours until removal of the CSF drain. The area under the curve (AUC) was determined for plasma and CSF IL-6, morphine, M3G, and M6G concentrations vs time. The primary endpoint measures were the correlations between the morphine, M6G, and M3G AUC CSF/plasma ratios and systemic inflammation as quantified by the time-normalized IL-6 exposure, which was calculated for each individual by dividing the total exposure (AUC) by time (t). A Bonferroni corrected P < 0.017 indicated a significant correlation.. Morphine distribution into the CSF was not significantly altered in patients undergoing thoracic aortic aneurysm repair. This suggests that BBB PGP function may not be affected by the perioperative inflammatory response.. www.clinicaltrials.gov , NCT 00878371. Registered 7 April 2009.

Topics: Aged; Aged, 80 and over; Analgesics, Opioid; Aortic Aneurysm, Thoracic; Area Under Curve; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Blood-Brain Barrier; Female; Humans; Inflammation; Male; Middle Aged; Morphine; Morphine Derivatives; Pain; Prospective Studies; Time Factors

Better knowledge of opioid pharmacology after Roux-en-Y gastric bypass (RYGB) is required for optimizing their use in this growing population.. The aim of this case-controlled pharmacokinetic (PK) study was to compare morphine and its glucuronidated metabolites (morphine-3-glucuronide and morphine-6-glucuronide) plasma PKs between patients with RYGB and their controls.. University hospital, Lariboisière Hospital, Paris.. Thirty milligrams of morphine as a sustained-release formulation was orally administered in 12 women who had undergone RYGB for at least 2 years (RYGB group) and in their nonsurgical controls matched for sex, body mass index (±2 points), and age (±5 yr). Morphine, morphine-3-glucuronide, and morphine-6-glucuronide plasma concentrations over a 12-hour period were determined by a validated method using liquid chromatography mass spectrometry in tandem. Drowsiness, respiratory rate, and oxygen saturation were monitored during the PK visit.. Morphine oral area under the curve (for time 0-12 hr; 115.8 ± 108.0 nmol.hr/L and 86.9 ± 38.8 nmol.hr/L for RYGB group and control group, respectively, P = .71), morphine at maximal concentration, metabolites oral area under the curve (for time 0-12 hr). No dose adjustment seems to be needed for sustained release morphine when prescribed to RYGB patients.

Topics: Administration, Oral; Adolescent; Adult; Aged; Analgesics, Opioid; Body Mass Index; Case-Control Studies; Chromatography, Liquid; Delayed-Action Preparations; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Gastric Bypass; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Obesity, Morbid; Pain, Postoperative; Young Adult

Sampling site, technique, and time influence postmortem drug concentrations. In 57 cases, we studied drug concentration differences as follows: subclavian vein-dissection/clamping versus blind stick, femoral vein-dissection/clamping versus blind stick, right cardiac chamber, and popliteal vein-dissection and clamping only. Cases were distributed in group #1 (all cases with both techniques), group #2 (dissection/clamping), and group #3 (blind stick). Sampled drugs were diazepam, methadone, morphine, and their metabolites. To assess PMR, mean concentrations and ratios were calculated for each group. Time-dependent variations of blood concentrations and ratios were also assessed. Results indicate that site, method, and time may influence postmortem distribution interpretation in different ways. Popliteal blood seems less subject to PMR. In conclusion, our study is the first to evaluate concurrently three main aspects of PMR and confirms that the popliteal vein may represent a site that is more resistant to the changes seen as a result of PMR.

Topics: Adult; Blood Specimen Collection; Chromatography, Liquid; Diazepam; Female; Femoral Vein; Forensic Toxicology; Humans; Male; Methadone; Middle Aged; Morphine; Morphine Derivatives; Nordazepam; Oxazepam; Popliteal Vein; Postmortem Changes; Subclavian Vein; Young Adult

Morphine dosing can be challenging in terminally ill adult patients due to the heterogeneous nature of the population and the difficulty of accurately assessing pain during sedation. To determine the pharmacokinetics of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in this population, and to find clinically relevant parameters for dose individualisation, we performed a population pharmacokinetic analysis.. Blood samples were randomly collected from 47 terminally ill patients in both the pre-terminal and terminal phases. Nonlinear mixed-effects modelling (NONMEM) was used to develop a population pharmacokinetic model and perform covariate analysis.. The data were accurately described by a two-compartment model for morphine with two one-compartment models for both its metabolites. Typical morphine clearance was 48 L/h and fell exponentially by more than 10 L/h in the last week before death. Decreased albumin levels and a decreased estimated glomerular filtration rate (eGFR) resulted in lower metabolite clearance. Between-subject variability in clearance was 52 % (morphine), 75 % (M3G) and 79 % (M6G), and changed to 53, 29 and 34 %, respectively, after inclusion of the covariates.. Our results show that morphine clearance decreased up to the time of death, falling by more than 10 L/h (26 %) in the last week before death, and that M3G and M6G accumulated due to decreased renal function. Further studies are warranted to determine whether dose adjustment of morphine is required in terminally ill patients.

Topics: Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Computer Simulation; Female; Glomerular Filtration Rate; Humans; Male; Metabolic Clearance Rate; Middle Aged; Models, Biological; Morphine; Morphine Derivatives; Prospective Studies; Serum Albumin; Terminally Ill

This article presents levels and tissue distribution of codeine, codeine-6-glucuronide (C6G), norcodeine, morphine and the morphine metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in post-mortem blood (peripheral and heart blood), vitreous fluid, muscle, fat and brain tissue in a series of 23 codeine-related fatalities. CYP2D6 genotype is also determined and taken into account. Quantification of codeine, C6G, norcodeine, morphine, M3G and M6G was performed with a validated solid phase extraction LC-MS method. The series comprise 19 deaths (83%) attributed to mixed drug intoxication, 4 deaths (17%) attributed to other causes of death, and no cases of unambiguous monointoxication with codeine. The typical peripheral blood concentration pattern in individual cases was C6G≫codeine≫norcodeine>morphine, and M3G>M6G>morphine. In matrices other than blood, the concentration pattern was similar, although in a less systematic fashion. Measured concentrations were generally lower in matrices other than blood, especially in brain and fat, and in particular for the glucuronides (C6G, M3G and M6G) and, to some extent, morphine. In brain tissue, the presumed active moieties morphine and M6G were both below the LLOQ (0.0080mg/L and 0.058mg/L, respectively) in a majority of cases. In general, there was a large variability in both measured concentrations and calculated blood/tissue concentration ratios. There was also a large variability in calculated ratios of morphine to codeine, C6G to codeine and norcodeine to codeine in all matrices, and CYP2D6 genotype was not a reliable predictor of these ratios. The different blood/tissue concentration ratios showed no systematic relationship with the post-mortem interval. No coherent degradation or formation patterns for codeine, morphine, M3G and M6G were observed upon reanalysis in peripheral blood after storage.

Topics: Adipose Tissue; Adult; Aged; Brain Chemistry; Chromatography, Liquid; Codeine; Cytochrome P-450 CYP2D6; Female; Forensic Toxicology; Genotype; Humans; Male; Mass Spectrometry; Middle Aged; Morphine; Morphine Derivatives; Muscle, Skeletal; Norway; Postmortem Changes; Solid Phase Extraction; Substance-Related Disorders; Tissue Distribution; Vitreous Body; Young Adult

The feasibility of intervention in heroin overdose is of clinical importance. The presence of 6-monoacetyl morphine (6MAM) in the blood is suggestive of survival times of less than 20-30 minutes following heroin administration. The study aimed to determine the proportions of cases in which 6MAM was present, and compare concentrations of secondary metabolites and circumstances of death by 6MAM status.. Analysis of cases of heroin-related death presenting to the Department of Forensic Medicine Sydney, 1 January 2013-12 December 2014.. Sydney, Australia.. A total of 145 cases. The mean age was 40.5 years and 81% were male.. Concentrations of 6MAM, free morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G). Circumstances of death included bronchopneumonia, apparent sudden collapse, location and other central nervous system (CNS) depressants.. 6MAM was detected in 43% [confidence interval (CI) = 35-51%] of cases. The median free morphine concentration of 6MAM-positive cases was more than twice that of cases without 6MAM (0.26 versus 0.12 mg/l). 6MAM-positive cases also had lower concentrations of the other major heroin metabolites: M3G (0.05 versus 0.29 mg/l), M6G (0.02 versus 0.05 mg/l) with correspondingly lower M3G/morphine (0.54 versus 2.71) and M6G/morphine (0.05 versus 0.50) ratios. Significant independent correlates of 6MAM were a higher free morphine concentration [odds ratio (OR) = 1.7], a lower M6G/free morphine ratio (OR = 0.5) and signs of apparent collapse (OR = 6.7).. In heroin-related deaths in Sydney, Australia during 2013 and 2014, 6- monoacetyl morphine was present in the blood in less than half of cases, suggesting that a minority of cases had survival times after overdose of less than 20-30 minutes. The toxicology of heroin metabolites and the circumstances of death were consistent with 6- monoacetyl morphine as a proxy for a more rapid death.

Topics: Adolescent; Adult; Australia; Autopsy; Drug Overdose; Female; Heroin; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Narcotics; Survival Rate; Young Adult

Morphine is metabolized in humans to morphine-3-glucuronide (M3G) and the pharmacologically active morphine-6-glucuronide (M6G). The hepatobiliary disposition of both metabolites relies upon multidrug resistance-associated proteins Mrp3 and Mrp2, located on the sinusoidal and canalicular membrane, respectively. Nonalcoholic steatohepatitis (NASH), the severe stage of nonalcoholic fatty liver disease, alters xenobiotic metabolizing enzyme and transporter function. The purpose of this study was to determine whether NASH contributes to the large interindividual variability and postoperative adverse events associated with morphine therapy. Male Sprague-Dawley rats were fed a control diet or a methionine- and choline-deficient diet to induce NASH. Radiolabeled morphine (2.5 mg/kg, 30 µCi/kg) was administered intravenously, and plasma and bile (0-150 or 0-240 minutes), liver and kidney, and cumulative urine were analyzed for morphine and M3G. The antinociceptive response to M6G (5 mg/kg) was assessed (0-12 hours) after direct intraperitoneal administration since rats do not produce M6G. NASH caused a net decrease in morphine concentrations in the bile and plasma and a net increase in the M3G/morphine plasma area under the concentration-time curve ratio, consistent with upregulation of UDP-glucuronosyltransferase Ugt2b1. Despite increased systemic exposure to M3G, NASH resulted in decreased biliary excretion and hepatic accumulation of M3G. This shift toward systemic retention is consistent with the mislocalization of canalicular Mrp2 and increased expression of sinusoidal Mrp3 in NASH and may correlate to increased antinociception by M6G. Increased metabolism and altered transporter regulation in NASH provide a mechanistic basis for interindividual variability in morphine disposition that may lead to opioid-related toxicity.

Topics: Animals; Infusions, Intravenous; Male; Morphine; Morphine Derivatives; Non-alcoholic Fatty Liver Disease; Rats; Rats, Sprague-Dawley; Tissue Distribution

The toxicodynamics and, to a lesser degree, toxicokinetics of the widely used opiate codeine remain a matter of controversy. To address this issue, analytical methods capable of providing reliable quantification of codeine metabolites alongside codeine concentrations are required. This article presents a validated method for simultaneous determination of codeine, codeine metabolites codeine-6-glucuronide (C6G), norcodeine and morphine, and morphine metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in post-mortem whole blood, vitreous fluid, muscle, fat and brain tissue by high-performance liquid chromatography mass spectrometry. Samples were prepared by solid-phase extraction. The validated ranges were 1.5-300 ng/mL for codeine, norcodeine and morphine, and 23-4,600 ng/mL for C6G, M3G and M6G, with exceptions for norcodeine in muscle (3-300 ng/mL), morphine in muscle, fat and brain (3-300 ng/mL) and M6G in fat (46-4,600 ng/mL). Within-run and between-run accuracy (88.1-114.1%) and precision (CV 0.6-12.7%), matrix effects (CV 0.3-13.5%) and recovery (57.8-94.1%) were validated at two concentration levels; 3 and 150 ng/mL for codeine, norcodeine and morphine, and 46 and 2,300 ng/mL for C6G, M3G and M6G. Freeze-thaw and long-term stability (6 months at -80°C) was assessed, showing no significant changes in analyte concentrations (-12 to +8%). The method was applied in two authentic forensic autopsy cases implicating codeine in both therapeutic and presumably lethal concentration levels.

Topics: Adipose Tissue; Autopsy; Brain; Calibration; Cause of Death; Chromatography, High Pressure Liquid; Codeine; Forensic Toxicology; Humans; Limit of Detection; Mass Spectrometry; Morphine Derivatives; Muscle, Skeletal; Opioid-Related Disorders; Reference Standards; Reproducibility of Results; Solid Phase Extraction; Substance Abuse Detection; Vitreous Body

Codeine's metabolic fate in the body is complex, and detailed quantitative knowledge of it, and that of its metabolites is lacking among prescribers. We aimed to develop a codeine pharmacokinetic pathway model for codeine and its metabolites that incorporates the effects of genetic polymorphisms. We studied the phenotype-specific time courses of plasma codeine, codeine-6-glucoronide, morphine, morphine-3-glucoronide, and morphine-6-glucoronide. A codeine pharmacokinetic pathway model accurately fit the time courses of plasma codeine and its metabolites. We used this model to build a population pharmacokinetic codeine pathway model. The population model indicated that about 10% of a codeine dose was converted to morphine in poor-metabolizer phenotype subjects. The model also showed that about 40% of a codeine dose was converted to morphine in EM subjects, and about 51% was converted to morphine in ultrarapid-metabolizers. The population model further indicated that only about 4% of MO formed from codeine was converted to morphine-6-glucoronide in poor-metabolizer phenotype subjects. The model also showed that about 39% of the MO formed from codeine was converted to morphine-6-glucoronide in extensive-metabolizer phenotypes, and about 58% was converted in ultrarapid-metabolizers. We conclude, a population pharmacokinetic codeine pathway model can be useful because beyond helping to achieve a quantitative understanding the codeine and MO pathways, the model can be used for simulation to answer questions about codeine's pharmacogenetic-based disposition in the body. Our study suggests that pharmacogenetics for personalized dosing might be most effectively advanced by studying the interplay between pharmacogenetics, population pharmacokinetics, and clinical pharmacokinetics.

Topics: Analgesics, Opioid; Codeine; Cytochrome P-450 CYP2D6; Humans; Male; Models, Biological; Morphine; Morphine Derivatives; Pharmacogenetics; Phenotype; Polymorphism, Genetic

The determination of morphine and its isobaric metabolites morphine-3-beta-d-glucuronide (M3G) and morphine-6-beta-d-glucuronide (M6G) is useful for therapeutic drug monitoring and forensic identification of drug use. In particular, capillary electrophoresis with mass spectrometry (CE-MS) represents an attractive tool for opioid analysis. Whereas volatile background electrolytes in CE often improve electrospray ionization for coupled MS detection, such electrolytes may reduce CE separation efficiency and resolution. To better understand the effects of background electrolyte (BGE) composition on separation efficiency and detection sensitivity, this work compares and contrasts method development for both volatile (ammonium formate and acetate) and nonvolatile (ammonium phosphate and borate) buffers. Peak efficiencies and migration times for morphine and morphine metabolites were optimal with a 25mM ammonium borate buffer (pH=9.5) although greater sensitivities were achieved in the ammonium formate buffer. Optimized CE methods allowed for the resolution of the isobaric morphine metabolites prior to high mass accuracy, electrospray ionization quadrupole time-of-flight (ESI-QTOF) MS detection applicable to the analysis of urine samples in under seven minutes. Urine sample preparation required only a 10-fold dilution with BGE prior to analysis. Limits of detection (LOD) in normal human urine were found to be 1.0μg/mL for morphine and 2.5μg/mL for each of M3G and M6G by CE-ESI-QTOF-MS. These LODs were comparable to those for CE-UV analysis of opioid standards in buffer, whereas CE-ESI-QTOF-MS analysis of opioid standards in buffer yielded LODs an order of magnitude lower. Patient urine samples (N=12) were analyzed by this new CE-ESI-QTOF-MS method and no significant difference in total morphine content relative to prior liquid chromatography-mass spectrometry (LC-MS) results was found as per a paired-t test at the 99% confidence level. Whereas the LC-MS method applied to these samples determined only total morphine content, this new CE-ESI-QTOF-MS method allowed for species differentiation in addition to total morphine determination. By this method, it was found that M3G and M6G metabolites were present in a 5:1 concentration ratio, on average, in patient samples. Therefore, the CE-ESI-QTOF-MS method not only allows for total morphine concentration determination comparable to established LC-MS methods, but also allows for differentiation between morphine and its

Topics: Electrophoresis, Capillary; Humans; Mass Spectrometry; Morphine; Morphine Derivatives

The functional impact of altered drug transport protein expression on the systemic pharmacokinetics of morphine, hepatically derived morphine glucuronide (morphine-3- and morphine-6-glucuronide), and fasting bile acids was evaluated in patients with biopsy-confirmed nonalcoholic steatohepatitis (NASH) compared to healthy subjects. The maximum concentration (Cmax ) and area under the concentration-time curve (AUC0-last ) of morphine glucuronide in serum were increased in NASH patients (343 vs. 225 nM and 58.8 vs. 37.2 µM*min, respectively; P ≤ 0.005); morphine pharmacokinetics did not differ between groups. Linear regression analyses detected an association of NASH severity with increased morphine glucuronide Cmax and AUC0-last (P < 0.001). Fasting serum glycocholate, taurocholate, and total bile acid concentrations were associated with NASH severity (P < 0.006). Increased hepatic basolateral efflux of morphine glucuronide and bile acids is consistent with altered hepatic transport protein expression in patients with NASH and may partially explain differences in efficacy and/or toxicity of some highly transported anionic drugs/metabolites in this patient population.

Topics: Adult; Analgesics, Opioid; Area Under Curve; Bile Acids and Salts; Cohort Studies; Female; Humans; Insulin Resistance; Liver; Liver Cirrhosis; Male; Middle Aged; Morphine Derivatives; Non-alcoholic Fatty Liver Disease

Development and validation of a selective, robust high-performance liquid chromatography-tandem mass spectrometric (HPLC/MS-MS) method for the quantification of morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine in human serum.. Drug-free human serum samples spiked with morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine were prepared by protein precipitation using methanol containing the internal standards. Samples were injected onto a Thermo Scientific AccuCore PFP column for chromatographic separation. Detection was achieved using a Thermo Scientific TSQ Vantage mass spectrometer. Assay validation followed the new Clinical and Laboratory Standards Institute (CLSI) C62-A guidelines.. The analytical measuring range for all analytes was determined to be 5 to 1000 ng/mL. Intra- and inter-assay precision for three quality control levels were ≤ 7.0% and ≤ 13.5%, respectively. Carryover, stability, linearity, matrix effects, extraction and processing efficiency and method comparison characteristics were acceptable relative to the CLSI C62 guidelines.. The validation of this HPLC-MS/MS method demonstrated a robust and rapid assay for the quantification of morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine.

Topics: Analgesics, Opioid; Chromatography, High Pressure Liquid; Guidelines as Topic; Humans; Hydromorphone; Linear Models; Morphine; Morphine Derivatives; Observer Variation; Reference Standards; Tandem Mass Spectrometry

The feasibility and clinical implication of drug monitoring of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) need further investigation. This study aimed to determine what predicts serum concentrations of morphine in cancer patients receiving continuously intravenous morphine, the relationships between serum concentration of morphine/its metabolites and urinary concentrations, and the relation between morphine concentrations and with clinical outcomes.. We collected serum and urine samples from 24 patients with advanced cancer undergoing continuously intravenous morphine therapy. Serum samples were obtained at day one. Spot urine samples were collected once daily on three consecutive days. Pain and adverse drug events were assessed using the Korean version of MD Anderson Symptom Inventory.. A total of 96 samples (72 urine and 24 serum samples) were collected. Median dose of morphine was 82.0 mg/24 h. In a multivariate analysis, total daily morphine dose was the most significant predictors of both serum and urine concentration of morphine. Morphine, M6G, and M3G in serum and urine were statistical significantly correlated (correlation coefficient = 0.81, 0.44, 0.56; p values < 0.01, 0.03, 0.01, respectively).. Spot urine concentrations of morphine and its metabolites were highly correlated to those of serum. Total dose of daily morphine was related to both serum and urine concentration of morphine and its metabolites.

Topics: Administration, Intravenous; Adult; Aged; Aged, 80 and over; Dose-Response Relationship, Drug; Drug Monitoring; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Republic of Korea

Morphine 3-β-D-glucuronide (M3G) and morphine 6-β-D-glucuronide (M6G) are the major metabolites of morphine in humans. More recently, morphine-3-β-d-glucoside (M-3-glucoside) was identified in the urine of patients treated with morphine. Kinetic and inhibition studies using human liver microsomes (HLM) and recombinant UGTs as enzyme sources along with molecular modeling were used here to characterize the relationship between morphine glucuronidation and glucosidation. The M3G to M6G intrinsic clearance (C(Lint)) ratio (∼5.5) from HLM supplemented with UDP-glucuronic acid (UDP-GlcUA) alone was consistent with the relative formation of these metabolites in humans. The mean C(Lint) values observed for M-3-glucoside by incubations of HLM with UDP-glucose (UDP-Glc) as cofactor were approximately twice those for M6G formation. However, although the M3G-to-M6G C(Lint) ratio remained close to 5.5 when human liver microsomal kinetic studies were performed in the presence of a 1:1 mixture of cofactors, the mean C(Lint) value for M-3-glucoside formation was less than that of M6G. Studies with UGT enzyme-selective inhibitors and recombinant UGT enzymes, along with effects of BSA on morphine glycosidation kinetics, were consistent with a major role of UGT2B7 in both morphine glucuronidation and glucosidation. Molecular modeling identified key amino acids involved in the binding of UDP-GlcUA and UDP-Glc to UGT2B7. Mutagenesis of these residues abolished morphine glucuronidation and glucosidation. Overall, the data indicate that morphine glucuronidation and glucosidation occur as complementary metabolic pathways catalyzed by a common enzyme (UGT2B7). Glucuronidation is the dominant metabolic pathway because the binding affinity of UDP-GlcUA to UGT2B7 is higher than that of UDP-Glc.

Topics: Glucosides; Glucuronides; Glucuronosyltransferase; HEK293 Cells; Humans; In Vitro Techniques; Kinetics; Microsomes, Liver; Molecular Docking Simulation; Morphine; Morphine Derivatives; Mutagenesis, Site-Directed; Protein Binding; Substrate Specificity

The objective of the current study was to describe the pharmacokinetics of morphine and its metabolites following intravenous administration to the horse. A total of eight horses (two per dose group) received a single intravenous dose of 0.05, 0.1, 0.2, or 0.5 mg/kg morphine. Blood samples were collected up to 72 h postdrug administration, analyzed using LC-MS/MS and pharmacokinetic parameters determined. Behavior, step counts, and gastrointestinal activity were also assessed. The beta and gamma half-life for morphine ranged from 0.675 to 2.09 and 6.70 to 18.1 h, respectively, following administration of the four different IV doses. The volume of distribution at steady-state and systemic clearance ranged from 6.95 to 15.8 L/kg and 28.3 to 35.7 mL · min/kg, respectively. The only metabolites identified in blood samples were the primary metabolites identified in other species, 3-morphine-glucuronide and 6-morphine-glucuronide. Muscle fasciculations were observed at 0.2 and 0.5 mg/kg and ataxia noted at 0.5 mg/kg. Gastrointestinal activity was decreased in all dose groups (for up to 8 h in 7/8 horses and 24 h in one horse). This study extends previous studies and is the first report describing the metabolites of morphine in the horse. Plasma concentrations of morphine-3-glucuronide, a metabolite with demonstrated neuro-excitatory activity in mice, far exceeded that of morphine-6-glucuronide. Further study is warranted to assess whether the high levels of the morphine-3-glucuronide contribute to the dose-dependent excitation observed at high morphine doses.

Topics: Analgesics, Opioid; Animals; Dose-Response Relationship, Drug; Female; Horses; Injections, Intravenous; Male; Morphine; Morphine Derivatives

Morphine is extensively metabolized to neurotoxic morphine-3-glucuronide (M3G) and opioid agonist morphine-6-glucuronide (M6G). Due to these different roles, interindividual variability and co-administration of drugs that interfere with metabolism may affect analgesia. The aim of the study was to investigate the repercussions of administration of an inducer (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) and an inhibitor (ranitidine) of glucuronidation in morphine metabolism and consequent analgesia, using the Guinea pig as a suitable model.. Thirty male Dunkin-Hartley guinea pigs were divided in six groups: control, morphine, ranitidine, ranitidine+morphine, TCDD and TCDD+morphine. After previous exposure to TCDD and ranitidine, morphine effect was assessed by an increasing temperature hotplate (35-52.5°C), during 60min after morphine administration. Then, blood was collected and plasma morphine and metabolites were quantified.. Animals treated with TCDD presented faster analgesic effect and 75% reached the cut-off temperature of 52.5°C, comparing with only 25% in morphine group. Animals treated with ranitidine presented a significantly lower analgesic effect, compared with morphine group (p<0.05). Moreover, significant differences between groups were found in M3G levels and M3G/morphine ratio (p<0.001 and p<0.0001), with TCDD animals presenting the highest values for M3G, M6G, M3G/morphine and M6G/morphine, and the lowest value for morphine. The opposite was observed in the animals treated with ranitidine.. Our results indicate that modulation of morphine metabolism may result in variations in metabolite concentrations, leading to different analgesic responses to morphine, in an animal model that may be used to improve morphine effect in clinical practice.

Topics: Analgesics, Opioid; Animals; Guinea Pigs; Male; Morphine; Morphine Derivatives; Pain; Pain Measurement; Polychlorinated Dibenzodioxins; Ranitidine

Ethanol and heroin are both depressant drugs on the central nervous system, and combined use is known to be dangerous due to pharmacodynamic interactions, leading to an even higher risk of respiratory depression and death. In addition, previous studies have suggested a pharmacokinetic interaction between ethanol and the metabolism of heroin. The aim of the present study was to investigate if there was a pharmacokinetic interaction between heroin and ethanol, by comparing concentrations of heroin metabolites in cases with and without ethanol, as detected in blood samples collected from a large material of forensic autopsy cases.. The material consisted of 1583 forensic autopsy cases, all containing 6-monoacetylmorphine (6-MAM), as evidence of heroin intake, in either blood or urine samples, from the time period between the 1st of January 2000 and the 31st of December 2012. Due to the high risk of post-mortem ethanol formation in cases revealing blood ethanol concentrations between 0.1 and 0.3‰, these cases were excluded from the study, along with cases where the analysis for ethanol was missing. After this exclusion of cases, the material (n=1474) was divided into two groups; one group where ethanol was not detected in blood (n=1160), and another group where ethanol was detected in blood at or above the concentration of 0.4‰ (n=314). Furthermore, the material was also divided into two other subgroups; one group where 6-MAM was detected in blood samples, indicating a very recent intake of heroin, and another group where 6-MAM was detected in the urine, but not in blood, indicating a less recent heroin intake.. The concentration ratios of morphine/6-MAM, morphine-3-glucuronide (M3G)/morphine, and morphine-6-glucuronide (M6G)/morphine in blood samples, were all significantly lower in the ethanol positive cases compared with that of the ethanol negative cases. For the subgroup of cases revealing a very recent intake of heroin (n=645), only the morphine/6-MAM ratio was significantly lower in the ethanol positive cases than in the ethanol negative cases. For the subgroup of cases with a less recent heroin intake (n=817), lower M3G/morphine and M6G/morphine ratios were found among the ethanol positive cases.. The results indicate that ethanol inhibits two steps in the heroin metabolism; the hydrolysis of 6-MAM to morphine, and the glucuronidation of morphine to M3G and M6G. This pharmacokinetic interaction could further complicate the outcome after combined use of heroin and ethanol, in addition to the already well-known pharmacodynamic interactions.

Topics: Central Nervous System Depressants; Drug Interactions; Ethanol; Forensic Toxicology; Heroin; Humans; Morphine Derivatives; Narcotics

Morphine is one of the most effective agents for the control of significant pain, primarily metabolized to morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G). While M6G is a potent opioid agonist, M3G has no opioid action and seems to have a role in side-effects caused by morphine. In this study, a reversed-phase high-performance liquid chromatographic method with diode-array and electrochemical detection was developed for the simultaneous determination of morphine, M3G and M6G in antemortem and postmortem samples (plasma, whole blood, urine, liver, kidney and brain). Morphine, glucuronides and internal standard were extracted by double solid-phase extraction and the separation was carried out with a Waters Spherisorb® ODS2 reversed-phase column and potassium phosphate buffer (pH = 2.2)–acetonitrile containing sodium dodecyl sulfate as the mobile phase. The method proved to be specific with good linearity for all analytes in a calibration range from 1 to 600 ng/mL and proved to be accurate and have adequate precision and recovery. Limits of detection in the studied matrices were 0.4–4.5 ng/mL for morphine, 2.7–6.1 ng/mL for M3G and 0.8–4.4 ng/mL for M6G. The proposed method can be successfully applied to quantify morphine and its metabolites in several biological samples, covering the major routes of distribution, metabolism and elimination of morphine.

Topics: Chromatography, High Pressure Liquid; Humans; Limit of Detection; Linear Models; Morphine; Morphine Derivatives; Postmortem Changes; Reproducibility of Results; Tissue Distribution

Assess association between UGT2B7 polymorphism -900G>A (rs7438135, also known as -842G>A) with morphine kinetics in preterm newborns undergoing mechanical ventilation.. Thirty-four infants were enrolled in a randomized clinical trial and allocated to rapid sequence intubation with remifentanil (1 µg/kg) or morphine (0.3 mg/kg). The latter group was included in our study.. Morphine plasma concentrations at 20 min post intubation were associated with postnatal age (p=0.017) and UGT2B7 -900G>A (p=0.036). UGT2B7 -900A allele carriers (n=13) had lower morphine levels compared with UGT2B7 -900G/G patients (n=2). Morphine-3-glucuronide and morphine-6-glucuronide plasma concentrations were only found to be associated with gestational and postnatal age. However, -900A allele carriers had a higher morphine-3-glucuronide:morphine metabolic ratio compared with patients genotyped as -900G/G (p=0.005), as determined by linear regression.. Our small pilot study illustrates that in addition to gestational and postnatal age, the UGT2B7 -900G>A polymorphism significantly alters morphine pharmacokinetics in preterm infants.

Topics: Female; Genetic Association Studies; Glucuronosyltransferase; Humans; Infant, Newborn; Morphine; Morphine Derivatives; Obstetric Labor, Premature; Piperidines; Polymorphism, Single Nucleotide; Pregnancy; Randomized Controlled Trials as Topic; Remifentanil

Ethanol and morphine are both substrates of uridine diphosphate glucuronosyl transferases (UGTs). A pharmacokinetic interaction between ethanol and morphine is suggested from in vitro studies, but to our knowledge not documented in vivo. The aim of this study was to compare the ratios between M6G and morphine and between M3G and morphine in blood samples from suspected drunk and drugged drivers, with and without presence of ethanol.. The data in the present study constitute all cases of suspected drunk and drugged driving positive for morphine, collected in Norway, in the period November 1st 2009 to December 1st 2012, during which all morphine positive cases were also routinely analysed for M6G and M3G. The cases were divided into two groups; one where morphine was present together with ethanol (group 1) and one where morphine was present in the absence of ethanol (group 2).. The ratios between M3G and morphine was lower in the ethanol positive cases, i.e. mean 4.9 (95 % CI 4.03-5.79) in group 1 and mean 6.7 (95 % CI 6.35-7.00) in group 2 (p < 0.001). The ratios between M6G and morphine was also lower in the ethanol positive cases, i.e. mean 0.62 (95 % CI 0.42-0.81) in group 1 and mean 0.96 (95 % CI 0.89-1.02) in group 2 (p = 0.001).. This study indicated that the metabolism of morphine may be changed in the presence of ethanol, resulting in less formation of the metabolites. This could lead to increased terminal half-life for morphine and also possibly more accumulation after repeated dosing.

Topics: Adult; Analgesics, Opioid; Ethanol; Female; Humans; Male; Morphine; Morphine Derivatives; Norway

In spite of numerous investigations and decades of research, there is still a void in the complete understanding of the therapeutic action of morphine due to the complex nature of its pharmacokinetic/metabolic disposition coupled with elusive pharmacodynamics. This commentary attempts to collate current information on this very important topic and provide perspective to further tease out the relationship between morphine and its metabolites to its purported clinical effect. Similar to numerous acute therapies that need a close vigil for therapy optimization, postoperative pain management with morphine is a challenge due to its extreme intrasubject variability, a fragile therapeutic index, and complex pharmacology interlinked with formation and transport of active metabolite(s). Although numerous investigations of pharmacokinetics and pharmacodynamic effects of morphine and its active glucuronide metabolites have been carried out and excellent data published, still there remains a void in complete understanding of desired therapeutic levels for a meaningful therapeutic outcome without the avoidance of morphine-related side effect profile. The 2009 report of Hammoud et al. (Pain. 2009;144:139-146) confirms the challenges of which one need to be aware during postoperative pain management with morphine in spite of well-controlled intravenous titration using an institutional protocol. These authors have attempted to correlate the plasma concentrations of morphine and its key metabolites, morphine-3-glucuronide (3MG) and morphine-6-glucuronide (6MG), with clinical outcomes such as sedation and adverse effects. This report assumes high significance, since such an investigation to titrate postoperative patients to a fixed desired clinical efficacy outcome has hitherto been not performed in patients who underwent postoperative pain managemnt. Moreover, the intravenous titration option used in the study provided a clean collection of pharmacokinetic surrogate data of morphine along with its metabolites without the issue of absorption and/or oral bioavailability setback if morphine was given by oral route. However, the various pharmacokinetic surrogates used in this study was found insufficient to distinguish the clinical effects. Given the complicated pharmacokinetic and pharmacodynamic profiles of morphine and its metabolites (6MG and 3MG), this commentary provides some thoughts to seek answers for this interesting dilemma.

Topics: Analgesics, Opioid; Humans; Morphine; Morphine Derivatives; Pain; Pain, Postoperative

Morphine is mainly transformed to morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in the liver. Glucuronidation is also performed by rat brain homogenates and UDP-glucuronosyltransferases (UGTs) are present in the brain. Here we investigated the possibility that microglia transforms morphine into its metabolites M3G and M6G. Primary cultures of neonatal rat microglia were incubated for different intervals of time in basal conditions or with different concentrations of morphine. The following measures were performed on these cultures and/or in the medium: (i) morphine as well as M3G and M6G concentrations; (ii) levels of mRNA coding for UGT1A1, UGT1A6, UGT1A7, and UGT2B1 as well as their protein levels; (iii) released prostaglandin (PG)E2 and nitrite concentrations. Results show that in basal conditions morphine and M3G are produced by microglia; accordingly, these cells expressed UGT1A1, UGT1A6 and UGT1A7, but not UGT2B1. When cultures were exposed to different concentrations of exogenous morphine, M6G was also synthesized. This shift in the glucuronidation was associated with variations in the expression of UGT isozymes. In particular, UGT1A7 expression was rapidly upregulated and this event was translated into enhanced protein levels of UGT1A7; lesser effects were exerted on UGT1A1 and UGT1A6. Upon prolonged exposure to morphine, microglial cell UGT expression returned to baseline conditions or even to reduced levels of expression. Morphine exposure did not affect the synthesis of both PGE2 and nitrites, ruling out a generalized priming of microglia by morphine. In conclusion, this study suggests that morphine glucuronides found in the cerebrospinal liquor upon peripheral morphine administration may at least in part be brain-born, reconciling the conceptual gap between the high hydrophilic features of morphine glucuronides and their presence beyond the blood-brain barrier.

Topics: Animals; Animals, Newborn; Calcium-Binding Proteins; Cells, Cultured; Cerebral Cortex; Chromatography, Liquid; Dinoprostone; Dose-Response Relationship, Drug; Gene Expression Regulation, Enzymologic; Glucuronosyltransferase; Microfilament Proteins; Microglia; Morphine; Morphine Derivatives; Narcotics; Nitrites; Rats; Tandem Mass Spectrometry; Time Factors

We have previously found that phenanthrenic opioids, including codeine, modulate morphine glucuronidation in the rat. Here codeine and five of its derivatives were compared in their effects on the synthesis of morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) from morphine by rat liver microsomal preparations, and by primary cultures of rat hepatocytes previously incubated for 72 h with either codeine or its derivatives. Acetylcodeine and pivaloylcodeine shared the capability of the parent compound of inhibiting the synthesis of M3G by liver microsomes through a noncompetitive mechanism of action. Their IC50 were 3.25, 2.27, and 4.32 μM, respectively. Dihydrocodeine, acetyldihydrocodeine, and lauroylcodeine were ineffective. In all the experimental circumstances M6G was undetectable in the incubation medium. In primary hepatocyte cultures codeine only inhibited M3G formation, but with a lower efficacy than that observed with microsomes (IC50 20.91 vs 4.32 μM). Preliminary results show that at micromolar concentrations codeine derivatives exhibit a low rate of affinity for μ opiate receptors. In conclusion, acetyl and pivaloyl derivatives of codeine noncompetitively inhibit liver glucuronidation of morphine interacting with microsomes. This study further strengths the notion that phenanthrenic opioids can modulate morphine glucuronidation independently from their effects on μ opiate receptors.

Topics: Animals; Codeine; Dose-Response Relationship, Drug; Hepatocytes; Kinetics; Male; Microsomes, Liver; Molecular Structure; Morphine Derivatives; Rats; Rats, Sprague-Dawley; Structure-Activity Relationship

Heroin is rapidly metabolized to morphine that in turn is transformed into morphine-3-glucuronide (M3G), an inactive metabolite at mu-opioid receptor (MOR), and morphine-6-glucuronide (M6G), a potent MOR agonist. We have found that rats that had received repeated intraperitoneal injections of heroin exhibit measurable levels of M6G (which is usually undetectable in this species).. The goal of the present study was to investigate whether M6G synthesis can be induced by intravenous (i.v.) heroin self-administration (SA).. Rats were trained to self-administer either heroin (50 μg/kg per infusion) or saline for 20 consecutive 6-h sessions and then challenged with an intraperitoneal challenge of 10 mg/kg of heroin. Plasma levels of heroin, morphine, 6-mono-acetyl morphine, M3G, and M6G were quantified 2 h after the challenge. In vitro morphine glucuronidation was studied in microsomal preparations obtained from the liver of the same rats.. Heroin SA induced the synthesis of M6G, as indicated by detectable plasma levels of M6G (89.7 ± 37.0 ng/ml vs. 7.35 ± 7.35 ng/ml after saline SA). Most important, the in vitro V (max) for M6G synthesis was correlated with plasma levels of M6G (r (2) = 0.78). Microsomal preparations from saline SA rats produced negligible amounts of M6G.. Both in vivo and in vitro data indicate that i.v. heroin SA induces the synthesis of M6G. These data are discussed in the light of previous studies conducted in heroin addicts indicating that in humans heroin enhances the synthesis of the active metabolite of heroin and morphine.

Topics: Animals; Heroin; Infusions, Intravenous; Injections, Intraperitoneal; Male; Microsomes, Liver; Morphine Derivatives; Rats; Rats, Sprague-Dawley; Self Administration

Morphine, codeine, morphine-6-glucuronide, and morphine-3-glucuronide are synthesized de novo in mammalian cells and in the central nervous system. Knowledge on endogenous morphine-like compound distribution in the adult mouse brain has been recently improved, and new hypotheses have been suggested about the potential implications in brain physiology. Endogenous morphine-like compounds have been shown to be synthesized in the spinal cord, but their localization is unknown. Here we describe the distribution of endogenous morphine-like compounds (morphine and/or its glucuronides and/or codeine) in the adult mouse spinal cord using a well-validated antibody. By using different microscopy approaches, we found the presence of morphine, codeine, or morphine glucuronides in γ-aminobutyric acid (GABA)-ergic neurons and astrocytes of the spinal cord. Whereas GABAergic neurons containing endogenous morphine-like compounds were located primarily in the ventral horn, astrocytes that were labeled for morphine-like compounds were found throughout the gray matter and the white matter. Our study demonstrates the possibility that endogenous morphine-like compounds in the central nervous system have other functions beyond their analgesic functions.

Topics: Animals; Astrocytes; Codeine; GABAergic Neurons; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Microscopy, Confocal; Microscopy, Electron, Transmission; Morphine; Morphine Derivatives; Spinal Cord

Undoubtedly, whole blood and vitreous humor have been biological samples of great importance in forensic toxicology. The determination of opiates and their metabolites has been essential for better interpretation of toxicological findings. This report describes the application of experimental design and response surface methodology to optimize conditions for enzymatic hydrolysis of morphine-3-glucuronide and morphine-6-glucuronide. The analytes (free morphine, 6-acetylmorphine and codeine) were extracted from the samples using solid-phase extraction on mixed-mode cartridges, followed by derivatization to their trimethylsilyl derivatives. The extracts were analysed by gas chromatography-mass spectrometry with electron ionization and full scan mode. The method was validated for both specimens (whole blood and vitreous humor). A significant matrix effect was found by applying the F-test. Different recovery values were also found (82% on average for whole blood and 100% on average for vitreous humor). The calibration curves were linear for all analytes in the concentration range of 10-1,500 ng/mL. The limits of detection ranged from 2.0 to 5.0 ng/mL. The method was applied to a case in which a victim presented with a previous history of opiate use.

Topics: Calibration; Codeine; Forensic Toxicology; Gas Chromatography-Mass Spectrometry; Glucuronidase; Glucuronides; Humans; Hydrolysis; Morphine Derivatives; Solid Phase Extraction; Spectrometry, Mass, Electrospray Ionization; Substance Abuse Detection; Vitreous Body

We have previously found that phenantrenic opioids, such as heroin or naltrexone, modulate morphine glucuronidation in the rat. Here we further investigated the effects of phenantrenic opioids on morphine glucuronidation comparing the effects of codeine and heroin. In particular, we measured the synthesis of morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) from morphine: in the liver microsomal preparations obtained from rats repeatedly treated with two different doses of codeine (ex vivo study); in primary cultures of rat hepatocytes previously incubated for 72h with codeine, or heroin (in vitro study); in the latter conditions, the levels of expression of genes coding for uridine-5'-diphosphate-glucuronosyltransferases (UGTs) A1, A6, A7 and 2B1 were also determined; finally, the levels of glucuronic acid in rat hepatocytes previously incubated for 72h with codeine or heroin were assessed. The ex vivo study shows that codeine exposure in vivo stimulated liver microsomal M3G formation and de novo synthesis of M6G. Differently, in primary hepatocyte cultures both codeine and heroin inhibited M3G formation, whereas heroin only stimulated de novo synthesis of M6G; moreover, codeine significantly reduced UGT2B1 expression at 6h and caused a trend toward inhibition of UGT1A1 expression at 72h; heroin enhanced UGT2B1 expression and inhibited that of UGT1A1 at 72h; finally, both codeine and heroin depleted UDPGA content of hepatocytes. In conclusion, codeine affects liver glucuronidation of morphine enlightening the possible contribution of changes in the spectrum of UGT gene expression and co-factor synthesis in this phenomenon.

Topics: Analgesics, Opioid; Animals; Cells, Cultured; Codeine; Gene Expression Regulation, Enzymologic; Glucuronosyltransferase; Hepatocytes; Male; Microsomes, Liver; Morphine; Morphine Derivatives; Rats; Rats, Sprague-Dawley; RNA, Messenger

Model validation procedures are crucial when models are to be used to develop new dosing algorithms. In this study, the predictive performance of a previously published paediatric population pharmacokinetic model for morphine and its metabolites in children younger than 3 years (original model) is studied in new datasets that were not used to develop the original model.. Six external datasets including neonates and infants up to 1 year were obtained from four different research centres. These datasets contained postoperative patients, ventilated patients and patients on extracorporeal membrane oxygenation (ECMO) treatment. Basic observed versus predicted plots, normalized prediction distribution error analysis, model refitting, bootstrap analysis, subpopulation analysis and a literature comparison of clearance predictions were performed with the new datasets to evaluate the predictive performance of the original morphine pharmacokinetic model.. The original model was found to be stable and the parameter estimates were found to be precise. The concentrations predicted by the original model were in good agreement with the observed concentrations in the four datasets from postoperative and ventilated patients, and the model-predicted clearances in these datasets were in agreement with literature values. In the datasets from patients on ECMO treatment with continuous venovenous haemofiltration (CVVH) the predictive performance of the model was good as well, whereas underprediction occurred, particularly for the metabolites, in patients on ECMO treatment without CVVH.. The predictive value of the original morphine pharmacokinetic model is demonstrated in new datasets by the use of six different validation and evaluation tools. It is herewith justified to undertake a proof-of-principle approach in the development of rational dosing recommendations - namely, performing a prospective clinical trial in which the model-based dosing algorithm is clinically evaluated.

Topics: Humans; Infant; Infant, Newborn; Infant, Premature; Metabolic Clearance Rate; Models, Biological; Morphine; Morphine Derivatives; Reproducibility of Results

A framework for the evaluation of paediatric population models is proposed and applied to two different paediatric population pharmacokinetic models for morphine. One covariate model was based on a systematic covariate analysis, the other on fixed allometric scaling principles.. The six evaluation criteria in the framework were 1) number of parameters and condition number, 2) numerical diagnostics, 3) prediction-based diagnostics, 4) η-shrinkage, 5) simulation-based diagnostics, 6) diagnostics of individual and population parameter estimates versus covariates, including measurements of bias and precision of the population values compared to the observed individual values. The framework entails both an internal and external model evaluation procedure.. The application of the framework to the two models resulted in the detection of overparameterization and misleading diagnostics based on individual predictions caused by high shrinkage. The diagnostic of individual and population parameter estimates versus covariates proved to be highly informative in assessing obtained covariate relationships. Based on the framework, the systematic covariate model proved to be superior over the fixed allometric model in terms of predictive performance.. The proposed framework is suitable for the evaluation of paediatric (covariate) models and should be applied to corroborate the descriptive and predictive properties of these models.

Topics: Child, Preschool; Computer Simulation; Forecasting; Humans; Infant; Infant, Newborn; Metabolic Clearance Rate; Models, Biological; Morphine Derivatives

Endogenous morphine, morphine-6-glucuronide, and codeine, which are structurally identical to vegetal alkaloids, can be synthesized by mammalian cells from dopamine. However, the role of brain endogenous morphine and its derivative compounds is a matter of debate, and knowledge about its distribution is lacking. In this study, by using a validated antibody, we describe a precise mapping of endogenous morphine-like compounds (morphine and/or its glucuronides and/or codeine) in the mouse brain. First, a mass spectrometry approach confirmed the presence of morphine and codeine in mouse brain, but also, of morphine-6-glucuronide and morphine-3-glucuronide representing two metabolites of morphine. Second, light microscopy allowed us to observe immunopositive cell somas and cytoplasmic processes throughout the mouse brain. Morphine-like immunoreactivity was present in various structures including the hippocampus, olfactory bulb, band of Broca, basal ganglia, and cerebellum. Third, by using confocal microscopy and immunofluroscence co-localization, we characterized cell types containing endogenous opiates. Interestingly, we observed that morphine-like immunoreactivity throughout the encephalon is mainly present in γ-aminobutyric acid (GABA)ergic neurons. Astrocytes were also labeled throughout the entire brain, in the cell body, in the cytoplasmic processes, and in astrocytic feet surrounding blood vessels. Finally, ultrastructural localization of morphine-like immunoreactivity was determined by electron microscopy and showed the presence of morphine-like label in presynaptic terminals in the cerebellum and postsynaptic terminals in the rest of the mouse brain. In conclusion, the presence of endogenous morphine-like compounds in brain regions not usually involved in pain modulation opens the exciting opportunity to extend the role and function of endogenous alkaloids far beyond their analgesic functions.

Topics: Animals; Astrocytes; Brain; Brain Chemistry; Codeine; Dopamine; gamma-Aminobutyric Acid; Humans; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Morphine; Morphine Derivatives; Neurons; Patch-Clamp Techniques

We studied the influence of three factors on drug disposition: genetic polymorphism, impaired renal excretion of drug metabolites, and the possible elimination by hemodialysis (HD), using codeine as a model drug.. Based on the genotyping of three CYP2D6 polymorphisms in 228 HD patients, nine extensive metabolizers (EMs) and two poor metabolizers (PMs) were given a single oral dose of 50 mg codeine phosphate. Plasma concentrations of its metabolites codeine-6-glucuronide (C6G), morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) were determined after 2, 4, 6, 8 and 24 h (beginning of the HD session) and again after 4 h of HD (28 h). Codeine metabolites in plasma were quantitated by liquid chromatography-mass spectrometry (LC-MS).. The concentrations of C6G in plasma were high and similar in EMs and PMs. Two hours after the codeine intake, the mean concentration of M3G was 210 nM in EMs vs. 3.5 nM in PMs. The M6G metabolite concentrations could be quantitated in EMs but were below the limit of quantification in PMs (<1 nM). All three codeine metabolites/glucuronides remained unchanged or even increased until the start of HD, and thereafter, the concentrations decreased dramatically during the HD procedure.. Formation of the codeine metabolites M3G and M6G was dependent on the CYP2D6 genotype, as previously shown in healthy individuals. Elimination of glucuronides in these patients was absent until HD was performed. These factors need to be taken into consideration when drugs metabolized by CYPs are prescribed in HD patients.

Topics: Administration, Oral; Aged; Biotransformation; Chromatography, Liquid; Codeine; Cytochrome P-450 CYP2D6; Female; Gene Frequency; Genotype; Humans; Kidney Failure, Chronic; Male; Middle Aged; Morphine Derivatives; Phenotype; Polymorphism, Genetic; Renal Dialysis; Spectrometry, Mass, Electrospray Ionization

The formation of morphine-3-glucuronide (M-3-G, pharmacologically inactive) and morphine-6-glucuronide (M-6-G, active metabolite) by liver microsomes from humans and rodents, including chimeric mice carrying human liver, was evaluated in the presence of fatty acyl-CoAs. Medium- to long-chain fatty acyl-CoAs, including oleoyl-CoAs, at a physiologic level (around 15 microM) markedly enhanced M-3-G formation catalyzed by rat liver microsomes. A separate experiment indicated that 15 microM oleoyl-CoA enhanced (14)C-UDP-glucuronic acid (UDPGA) uptake by microsomes. The activation by acyl-CoAs disappeared or was greatly reduced by either pre-treating microsomes with detergent or freezing/thawing the rat liver before preparation. Many of the microsomes prepared from frozen human livers (N=14) resisted oleoyl-CoA-mediated activation of UDP-glucuronosyltransferase (UGT) activity, including M-6-G formation, which is highly specific to humans. In sharp contrast, the activity of M-6-G and M-3-G formation in freshly-prepared hepatic microsomes from chimeric mice with humanized liver was potently activated by oleoyl-CoA. Thus, acyl-CoAs activate morphine glucuronidation mediated by human as well as rat UGTs. This activation is assumed to be due to the acyl-CoA-facilitated transportation of UDPGA, and microsomes need to maintain the intact conditions required for the activation. The function of UGT appears to be dynamically changed depending on the cellular acyl-CoA level in many species.

Topics: Acyl Coenzyme A; Animals; Cryopreservation; Female; Glucuronosyltransferase; Hepatocytes; Humans; Liver; Male; Mice; Microsomes, Liver; Morphine; Morphine Derivatives; Rats; Transplantation Chimera

To propose a method for simultaneous determination of codeine(COD), 6-monoacetyl-morphine (6-MAM), morphine (MOR), morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in human urine by ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS).. After precipitation of protein by acetonitrile, the urine samples, with added the morphine-d3 (MOR-d3) and morphine-3-Glucuronide-d3 (M3G-d3) as internal standards, were pre-treated by Sirocco protein precipitation plate, and then analyzed by UPLC-MS/MS.. The limit of detection was 0.2 ng/mL for both COD and MAM, the limit of quantitation was 0.5 ng/mL for both COD and MAM. The limit of detection was 0.5 ng/mL for MOR, M3G and M6G, the limit of quantitation was 1 ng/mL for them. The linear correlation coefficients were not less than 0.9997, both the inter-day and intra-day precisions were less than 10%, the recoveries were in the range of 70.0% to 98.3%, the matrix effects were about 50.5% to 99.0%.. This proposed method is simple, rapid and accurate, it could be applied in forensic toxicological analysis.

Topics: Chromatography, Liquid; Codeine; Humans; Limit of Detection; Morphine; Morphine Derivatives; Reproducibility of Results; Sensitivity and Specificity; Substance Abuse Detection; Tandem Mass Spectrometry

This study was undertaken to investigate the relationship between the plasma concentration of morphine, morphine-3-glucuronide and morphine-6-glucuronide and pain in cancer patients receiving oral morphine.. The trough value of plasma concentrations of morphine and its metabolites were measured by high performance liquid chromatography using an ultraviolet detector. Using this assay system, the plasma concentrations of morphine, morphine-3-glucuronide and morphine-6-glucuronide in 26 cancer pain patients were measured and compared with pain intensity. The pain intensity was assessed at the time of blood sampling using the visual analog scale.. The trough value of morphine and morphine-6-glucuronide did not show a significant correlation with pain intensity by visual analog scale assessment, but morphine-3-glucuronide and the ratio of morphine-3-glucuronide/morphine showed a significantly positive correlation (r = 0.528, P = 0.006 and r = 0.671, P < 0.001, respectively). By dividing the group according to low (≤ median value) or high (> median value) VAS scores a significant difference was found between the two groups in morphine-3-glucuronide and the ratio of morphine-3-glucuronide/morphine (P = 0.045 and P = 0.007, respectively).. These results indicated that the level of morphine-3-glucuronide is related to the patient's perception of morphine effect, and the plasma concentration of morphine-3-glucuronide and the ratio of morphine-3-glucuronide/morphine indicated potency to assess clinical effect.

Topics: Administration, Oral; Aged; Analgesics, Opioid; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Pain Measurement

A hybrid quadrupole linear ion-trap mass spectrometer using an electrospray ionisation ion source coupled to a HPLC system has been used to develop a method which can accurately measure morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in plasma, whole blood and post-mortem blood following solid-phase extraction. The method can also qualitatively detect various other opioids and related compounds including: codeine, dihydrocodeine (and metabolites), noscapine, papaverine and 6-acetylmorphine (6-AM). The method has been favourably compared to an existing laboratory method using a now discontinued radio-immunoassay technique. The advantage of measuring the glucuronides directly rather than following deconjugation by beta-glucuronidase has also been shown. Detection and quantification of compounds was achieved using multiple reaction monitoring (MRM) incorporating the use of deuterated morphine and M3G as internal standards. Precision and accuracy was determined to be less than 10% at both high and low levels for all analytes and the calibration curve was deemed linear over an acceptable range. Recovery in blood was greater than 90% and ion suppression/enhancement was shown to be less than 15%. This method was applied to over 130 post-mortem cases involving the use of heroin, prescribed morphine and codeine. The range of concentrations of morphine, M3G and M6G was large (particularly in heroin and prescribed morphine cases), reflecting the many different factors involved with therapeutic use or fatal opiate poisonings, including tolerance associated with regular use, variable dose regimens and co-administration of other drugs. Detection of other constituents of the opium poppy such as noscapine and papaverine and metabolites of diacetylmorphine in the blood (6-AM) was useful in determining the source of the morphine (i.e. illicit heroin) and the rapidity of death after administration.

Topics: Calibration; Chromatography, High Pressure Liquid; Drug Stability; Glucuronidase; Humans; Hydrolysis; Illicit Drugs; Morphine; Morphine Derivatives; Postmortem Changes; Radioimmunoassay; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization; Substance Abuse Detection

This work presents two cases of codeine intoxication in 3-year-old monozygotic twin brothers while treated with a codeine slow-release formulation. One child had to be admitted to the hospital, whereas the other one died at home after aspiration of gastric content. The concentrations of codeine and major metabolites including morphine and corresponding glucuronide conjugates were measured by liquid chromatography-tandem mass spectrometry in serum, urine, cerebrospinal fluid, and brain tissue, respectively. A genetic polymorphism study was carried out in order to determine the ability of the children to metabolize codeine by O-demethylation. A pharmacokinetic calculation was also performed to estimate the administered dose of codeine in question. High concentrations of all substances were found in samples of both children. The pharmacokinetic estimate suggests an overdose of codeine, and the possible reasons for the high opiate concentrations are discussed. Furthermore, the postmortem distribution--during and after resuscitation--might play a major role in the interpretation of postmortem concentration levels.

Topics: Antitussive Agents; Brain Chemistry; Brain Edema; Child, Preschool; Chromatography, Liquid; Codeine; Cytochrome P-450 CYP2D6; Delayed-Action Preparations; Drug Overdose; Fatal Outcome; Forensic Toxicology; Genotype; Glucuronides; Humans; Medication Errors; Morphine; Morphine Derivatives; Polymorphism, Genetic; Respiratory Aspiration; Tandem Mass Spectrometry; Tissue Distribution; Twins, Monozygotic

After intake of heroin or morphine, active metabolites are formed in the body. The two most important morphine metabolites are morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G). M6G and M3G are present for longer time periods and in higher concentrations than the parent drug, but their potential contribution to reward and to development of dependence and addiction is not clear. We tested the effects of morphine and M6G separately (doses of 10, 20, 30 and 50 micromol/kg), administered together, and also in combination with with 200 microm l/kg M3G in male C57BL/6J-Bom mice. M3G in doses of 50, 100, 200, 300 and 400 micromol/kg were also tested alone. We evaluated the rewarding effects in a conditioning place preference (CPP) model and the psychomotor stimulating effects by recording locomotor activity. Mice were subjected to three consecutive conditioning days with drugs or saline before testing. Changes in locomotor activity from conditioning day one to day three were also compared to the expression of CPP on the test day. This study revealed that coadministration of morphine and M6G induced CPP of similar magnitude to the sum of equimolar doses of these compounds alone, and different ratios of the two drugs did not affect the results. M3G did not cause CPP and reduced the CPP induced by both morphine and M6G when coadministered with these drugs. Morphine induced locomotor activity was reduced by coadministration of M3G, but this was not seen when M3G was co-injected with M6G. The changes in locomotor activity during the conditioning periods did not correlated with the expression of CPP. This study revealed that the morphine-glucuronides in different and complex ways can influence the pharmacological effects of psychomotor activation and reward observed after intake of morphine.

Topics: Animals; Conditioning, Psychological; Dose-Response Relationship, Drug; Drug Interactions; Male; Mice; Mice, Inbred C57BL; Morphine; Morphine Derivatives; Motor Activity; Reward; Substance-Related Disorders; Time Factors

Topics: Analgesics, Opioid; Animals; Hyperalgesia; Mice; Mice, Knockout; Morphine; Morphine Derivatives; Receptors, Opioid, delta; Receptors, Opioid, kappa; Receptors, Opioid, mu

Topics: Analgesics, Opioid; Animals; Dopamine; Male; Mice; Mice, Inbred C57BL; Morphine Derivatives; Nucleus Accumbens; Receptors, Opioid, mu

Topics: Clinical Competence; Expert Testimony; Forensic Toxicology; Heroin; Humans; Morphine; Morphine Derivatives; Narcotics; Suicide, Assisted; Terminally Ill

In animals, central nervous system inflammation increases drug accumulation in the brain partly due to a loss of central nervous system drug efflux transporter function at the blood-brain barrier. To determine whether a similar loss of active drug efflux occurs in humans after acute inflammatory brain injury.. Observational human pharmacokinetic study.. Medical-surgical-neurosurgical intensive care unit at a university-affiliated, Canadian tertiary care center.. Patients with acute inflammatory brain injury, including subarachnoid hemorrhage (n = 10), intracerebral and/or intraventricular hemorrhage (n = 4), or closed head trauma (n = 2) who received morphine intravenously after being fitted with cerebrospinal fluid ventriculostomy and peripheral arterial catheters.. We correlated the cerebrospinal fluid distribution of morphine, morphine-3-glucuronide, and morphine-6-glucuronide with the cerebrospinal fluid and plasma concentration of the proinflammatory cytokine interleukin-6 and the passive marker of blood-brain barrier permeability, albumin.. Acute brain injury produced a robust inflammatory response in the central nervous system as reflected by the elevated concentration of interleukin-6 in cerebrospinal fluid. Penetration of morphine metabolites into the central nervous system increased in proportion to the neuroinflammatory response as demonstrated by the positive correlation between cerebrospinal fluid interleukin-6 exposure and the area under the curve cerebrospinal fluid/plasma ratio for morphine-3-glucuronide (r = .49, p < .001) and morphine-6-glucuronide (r = .51, p < .001). In contrast, distribution of morphine into the brain was not linked with cerebrospinal fluid interleukin-6 exposure (r = .073, p = .54). Albumin concentrations in plasma and cerebrospinal fluid were consistently in the normal range, indicating that the physical integrity of the blood-brain barrier was likely undisturbed.. Our results suggest that central nervous system inflammation following acute brain injury may selectively inhibit the activity of specific drug efflux transporters within the blood-brain barrier. This finding may have significant implications for patients with neuroinflammatory conditions when administered centrally acting drugs normally excluded from the brain by such transporters.

Topics: Adult; Aged; Analgesics, Opioid; Blood-Brain Barrier; Brain; Cerebral Hemorrhage; Critical Care; Dose-Response Relationship, Drug; Female; Head Injuries, Closed; Humans; Interleukin-6; Male; Metabolic Clearance Rate; Middle Aged; Morphine; Morphine Derivatives; Serum Albumin; Subarachnoid Hemorrhage; Ventriculostomy

Topics: Analgesics, Opioid; ATP-Binding Cassette Transporters; Blood-Brain Barrier; Brain; Cerebral Hemorrhage; Conscious Sedation; Critical Care; Dose-Response Relationship, Drug; Head Injuries, Closed; Humans; Interleukin-6; Metabolic Clearance Rate; Morphine; Morphine Derivatives; Subarachnoid Hemorrhage

Sensitization is thought to be involved in central aspects of drug addiction. Both morphine-3-glucuronid (M3G) and morphine-6-glucuronid (M6G) are rapidly formed in high concentrations shortly after heroin and morphine consumption. Their role in the development of sensitization has not previously been studied. In our study, mice received three injections of M6G or morphine at six day intervals. M6G induced locomotor sensitization comparable to morphine as early as the first injection. In a second experiment two injections of M6G or morphine were given, separated by 6, 12, 18, 24 or 30 days. A sensitized response was observed for both morphine and M6G up to 18 days after the first injection. In a third experiment with two injections, the first with M6G and the second with morphine, or the opposite sequence, M6G did not induce cross-sensitization to morphine although morphine induced cross-sensitization to M6G. Finally, pretreatment with M3G induced sensitization of morphine locomotor activity but not M6G. In conclusion M6G induced long-lasting sensitization similar but not identical to morphine. M3G was shown to sensitize morphine induced locomotor activity in a similar way to morphine pretreatment. This suggests that morphine-glucuronide metabolites may play a role in the development of addiction to morphine.

Topics: Analgesics, Opioid; Animals; Behavior, Animal; Brain Chemistry; Chromatography, High Pressure Liquid; Male; Mice; Mice, Inbred C57BL; Morphine Derivatives; Motor Activity

UDP-glucuronosyltransferase 2B7 (UGT2B7) plays a central role in the liver-mediated biotransformation of endogenous and exogenous compounds. The genetic basis of interindividual variability in UGT2B7 function is unknown. This study aimed to discover novel gene variants of functional significance.. Caucasian human livers (n=54) were used. UGT2B7 was resequenced in 12 samples [(six highest and six lowest for the formation of morphine-3-glucuronide (M3G)]. Haplotype-tagging single nucleotide polymorphisms were genotyped in the entire sample set. Samples were phenotyped for mRNA expression.. 10 haplotype-tagging single nucleotide polymorphisms were identified and their haplotypes were inferred. Haplotype 4 (-45597G; -6682_-6683A; 372A; IVS1+9_IVS1+10A; IVS1+829T; IVS1+985G; IVS1+999C; IVS1+1250G; 801T; IVS4+185C) (frequency of 0.12) was associated with an increase in enzyme activity and gene expression. The 1/4 and 4/6 diplotypes had higher M3G formation compared with 1/1 (P<0.05) and 2/3 (P<0.01) diplotypes. Diplotypes containing haplotype 4 resulted in a significant 45% average increase in the formation of M3G compared with diplotypes without haplotype 4 (P=0.002). There was also an association between haplotype 4 and increased mRNA expression. IVS1+985A>G, 735A>G, and 1062C>T are the putative functional variants of haplotype 4. We also identified two mRNA splicing variants (UGT2B7_v2 and UGT2B7_v3) splicing out exon 1, 4, 5, and 6 but sharing exons 2 and 3 with the involvement of additional 5' exons. UGT2B7_v2 was detected in all livers tested, but UGT2B7_v3 was present at much lower levels compared with UGT2B7_v2. The UGT2B7 reference sequence mRNA is now named UGT2B7_v1.. UGT2B7 haplotype 4 is functional and its effects on the biotransformation of UGT2B7 substrates should be tested in controlled clinical trials. Biochemical studies should investigate the functional role of the newly discovered mRNA splicing variants.

Topics: Alternative Splicing; Base Sequence; Epirubicin; Exons; Gene Expression Regulation, Enzymologic; Genetic Variation; Glucuronosyltransferase; Haplotypes; Humans; Liver; Molecular Sequence Data; Morphine Derivatives; Phenotype; Polymorphism, Single Nucleotide; Regression Analysis; RNA, Messenger; Sequence Analysis, DNA

It has been reported that morphine-6-glucuronide inhibits small intestinal transit in mice more potently than morphine. In this study, we investigated the effects of morphine, morphine-6-glucuronide and morphine-3-glucuronide on the contractile response of the circular muscle isolated from mouse ileum. Morphine and morphine-6-glucuronide induced tonic contraction dose-dependently, and the contractile force of morphine-6-glucuronide was greater than that of morphine. Morphine-3-glucuronide induced slight contraction at high dose. These results suggest that the strong contraction induced by morphine-6-glucuronide contributed to the inhibition of small intestinal transit in mice.

Topics: Animals; Dose-Response Relationship, Drug; Gastrointestinal Transit; Ileum; Male; Mice; Morphine; Morphine Derivatives; Muscle Contraction

The common adverse effect of centrally-injected mu-opioid receptor (mu-OR) agonists is pruritus. This study was conducted using mice to examine whether different subtypes of mu-OR would be responsible for pruritus and analgesia. Intracisternal injections of morphine and morphine-6beta-glucronide (M6G), but not M3G, produced an antinociceptive effect. Morphine, but neither M6G nor M3G, induced facial scratching, a pruritus-related response. Facial scratching following morphine was not affected by the mu(1)-OR antagonist naloxonazine at doses that inhibited the antinociceptive effects. The results suggest that different subtype and/or splice variants of mu-OR are separately involved in pruritus and antinociception of opioids.

Topics: Analgesics, Opioid; Animals; Behavior, Animal; Dose-Response Relationship, Drug; Injections, Subcutaneous; Male; Mice; Mice, Inbred ICR; Morphine; Morphine Derivatives; Naloxone; Narcotic Antagonists; Pain Measurement; Pain Threshold; Pruritus; Receptors, Opioid, mu; Time Factors

A cation-selective exhaustive injection and sweeping micellar EKC (CSEI-Sweep-MEKC) was established to analyze morphine and its four metabolites, including codeine, normorphine (NM), morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G). After SPE, the urine samples were analyzed by this CE method. The phosphate buffer (75 mM, pH 2.5) containing 30% methanol was first filled into an uncoated fused-silica capillary (40 cm, 50 microm id), then a high-conductivity buffer (120 mM phosphate, 10.3 kPa for 99.9 s) followed. The pretreated urine sample was loaded by electrokinetic injection (10 kV, 600 s). The stacking and separation were performed by using phosphate buffer (25 mM, pH 2.5) containing 22% methanol and 100 mM SDS at -20 kV, and detected at 200 nm. During method validation, calibration plots were linear (r > or = 0.998) over a range of 30-3000 ng/mL for morphine, NM, and codeine, 100-2000 ng/mL for M6G, and 80-3200 ng/mL for M3G. The LODs (S/N = 5, sampling 600 s at 10 kV) were 10 ng/mL for morphine, NM, and codeine, 35 ng/mL for M6G, and 25 ng/mL for M3G. This stacking CE method could increase 2500-fold sensitivity of codeine, when comparing with CZE. Five addicts' urine specimens were analyzed. Their results were compared with those of LC-MS-MS, and showed good coincidence. This method could be feasible for monitoring morphine and its metabolites in forensic interest and pharmacokinetic investigations.

Topics: Chromatography, Liquid; Chromatography, Micellar Electrokinetic Capillary; Codeine; Humans; Morphine; Morphine Dependence; Morphine Derivatives; Reproducibility of Results; Solid Phase Extraction; Tandem Mass Spectrometry

The main metabolite of morphine, morphine-3-glucuronide (M3G) has no opioid effects. Some studies have rather indicated that it antagonizes the antinociceptive and respiratory depressive effects of both morphine and the active metabolite morphine-6-glucuronide (M6G). We studied the possible influence of M3G on the psychostimulant properties of morphine and M6G measured by locomotor activity. Mice were given two injections, one with either 80, 240 or 500 micromol/kg M3G or saline followed by an injection of 20 or 30 micromol/kg morphine or M6G. M3G influenced the locomotor activity induced by both morphine and M6G, but in opposite directions. M3G reduced the morphine induced locomotor activity during the first hour following morphine injection in a concentration dependent manner. M3G pretreatment did not significantly influence brain concentrations of morphine indicating that the interaction was of a pharmacodynamic type. In contrast M3G pretreatment increased the M6G induced locomotor activity. M3G pretreatment increased serum and brain M6G concentrations to an extent indicating that this interaction was mainly of a pharmacokinetic type. In conclusion our results disclose complicated interactions between morphine and its two metabolites with respect to induction of locomotor activity and possibly also with respect to mechanisms related to drug reward.

Topics: Animals; Brain; Dose-Response Relationship, Drug; Drug Interactions; Male; Mice; Mice, Inbred C57BL; Morphine; Morphine Derivatives; Motor Activity; Reward

Flurbiprofen is a nonsteroidal anti-inflammatory drug used as a racemic mixture. Although glucuronidation is one of its elimination pathways, the role of UDP-glucuronosyltransferase (UGT) in this process remains to be investigated. Thus, the kinetics of the stereoselective glucuronidation of racemic (R,S)-flurbiprofen by recombinant UGT isozymes and human liver microsomes (HLMs) were investigated, and the major human UGT isozymes involved were identified. UGT1A1, 1A3, 1A9, 2B4, and 2B7 showed glucuronidation activity for both (R)- and (S)-glucuronide, with UGT2B7 possessing the highest activity. UGT2B7 formed the (R)-glucuronide at a rate 2.8-fold higher than that for (S)-glucuronide, whereas the other UGTs had similar formation rates. The glucuronidation of racemic flurbiprofen by HLMs also resulted in the formation of (R)-glucuronide as the dominant form, which occurred to a degree similar to that by recombinant UGT2B7 (2.1 versus 2.8). The formation of (R)-glucuronide correlated significantly with morphine 3-OH glucuronidation (r = 0.96, p < 0.0001), morphine 6-OH glucuronidation (r = 0.91, p < 0.0001), and 3'-azido-3'-deoxythymidine glucuronidation (r = 0.85, p < 0.0001), a reaction catalyzed mainly by UGT2B7, in individual HLMs. In addition, the formation of both glucuronides correlated significantly (r = 0.99, p < 0.0001). Mefenamic acid inhibited the formation of both (R)- and (S)-glucuronide in HLMs with similar IC(50) values (2.0 and 1.7 muM, respectively), which are close to those in recombinant UGT2B7. In conclusion, these findings suggest that the formation of (R)- and (S)-glucuronide from racemic flurbiprofen is catalyzed by the same UGT isozyme, namely UGT2B7.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Dideoxynucleosides; Dose-Response Relationship, Drug; Enzyme Inhibitors; Flurbiprofen; Glucuronides; Glucuronosyltransferase; Humans; Kinetics; Liver; Mefenamic Acid; Metabolic Detoxication, Phase II; Microsomes, Liver; Morphine; Morphine Derivatives; Recombinant Proteins; Stereoisomerism; UDP-Glucuronosyltransferase 1A9; Zidovudine

Morphine is an analgesic drug used for the treatment of acute and chronic pain syndromes for cancer patients. Glucuronidation is a major pathway of the elimination of morphine in humans. Morphine is metabolized to 3-glucuronide (no analgesic effect) and 6-glucuronide (more potently analgesic than morphine) mainly by UGT2B7. In the present study, we investigated the inhibitory effects of a variety of drugs on the morphine glucuronosyltransferase activities in human liver microsomes. Twenty-one drugs including anticancer drugs, immunosuppressants, analgesics, anticonvulsants, antidepressants, antipsychotic drugs were selected in this study, because they are frequently co-administered with morphine. We found that 10 out of 21 drugs, tamoxifen, tacrolimus, diclofenac, carbamazepine, imipramine, clomipramine, amitriptyline, diazepam, lorazepam and oxazepam extensively inhibited the morphine 3- and 6-glucuronosyltransferase activities. Although some of the drugs are not substrates of UGT2B7, they would be potent inhibitors of UGT2B7. If patients receive morphine and these drugs simultaneously, the drug-drug interaction may change the levels of morphine and these glucuronides, resulting in altered analgesic efficacy and the risk of side effects. The results presented here will assist clinicians in choosing the proper drugs and/or dosages, and enable them to anticipate potential drug-drug interactions.

Topics: Analgesics, Opioid; Drug Interactions; Enzyme Inhibitors; Glucuronides; Glucuronosyltransferase; Humans; In Vitro Techniques; Liver; Microsomes, Liver; Models, Biological; Morphine; Morphine Derivatives; Predictive Value of Tests; Risk Assessment; Uridine Diphosphate Glucuronic Acid

There is great variability in the need for morphine in the postoperative period. We performed a pharmacokinetic-pharmacodynamic study considering the potential effect of the two main metabolites of morphine.. Fifty patients with moderate to severe pain received morphine as an IV titration, followed by IM administration postoperatively. The plasma concentration of morphine, morphine-6-glucuronide (M-6-G), morphine-3-glucuronide (M-3-G), and pain intensity were measured at frequent intervals. Pharmacokinetic and pharmacodynamic fitting was performed with the software NONMEM.. The pharmacokinetics were largely predictable. M-6-G and M-3-G clearances were markedly decreased in patients with renal failure. The pharmacodynamics was less predictable, with an important interindividual variability. M-6-G was 7.8 times more potent than morphine, but the average time to peak concentration in the effect compartment after a bolus injection of morphine was 4.25 h for M-6-G, when compared to 0.33 h for morphine. M-3-G showed mild inhibition of the analgesic properties of morphine and of M-6-G. The time to M-3-G peak concentration in the effect compartment after a bolus injection of morphine was 10 h.. M-6-G is a potent opioid agonist and M-3-G a mild opioid antagonist. Both are poorly excreted in patients with renal failure. However, the metabolism of morphine was rapid when compared to the transfer of metabolites through the blood-brain barrier, which appears to be the limiting process. Because poor analgesia due to M-3-G's effect may occur in some patients after 1 or 2 days, a switch to other molecules should be considered.

Topics: Adult; Aged; Female; Humans; Male; Metabolic Networks and Pathways; Middle Aged; Morphine; Morphine Derivatives; Pain, Postoperative; Postoperative Period

Fetal metabolism significantly contributes to the clearance of drugs from the fetus. To understand how the changes in fetal metabolism expected in late gestation alter fetal drug clearance, serial measurements of morphine metabolism were made in the fetal baboon over the latter third of gestation. Clearance and metabolism were evaluated in the context of fetal growth, onset of labor, and the administration of classical enzyme induction agents. Morphine, a probe substrate for the enzyme uridine diphosphate glucuronosyltransferase 2B7 (UGT2B7), was continuously infused to chronically catheterized fetal baboons while measuring morphine, morphine-3-beta-glucuronide, and morphine-6-beta-glucuronide concentrations. In some animals, intermittent infusions of the metabolites provided estimates of metabolite clearance and, hence, the rate of formation of metabolites and metabolic clearance. Overall, metabolic clearance of morphine from the fetus was 27 +/- 9.0 ml x min(-1) or 32% of total clearance. This is similar to the overall clearance in the adult baboon when standardized to weight. No change in any measure of metabolism or clearance of morphine or its glucuronide metabolites was found with gestational age, the presence of labor, or administration of UGT enzyme induction agents. Interpreting these findings using a physiologically based approach suggests that the intrinsic clearance of the fetal liver toward morphine is of sufficient magnitude that fetal hepatic clearance is flow-limited. The implication of a high intrinsic clearance is for significant placento-hepatic first-pass metabolism when drugs are administered to the mother. The previously held view of the "inadequacy of perinatal glucuronidation" needs to be reconsidered.

Topics: Analgesics, Opioid; Animals; Female; Fetus; Gestational Age; Infusions, Intravenous; Liver; Metabolic Clearance Rate; Morphine; Morphine Derivatives; Papio; Placenta; Pregnancy

To determine the in vitro kinetics of morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) formation and the inhibition potential by methadone enantiomers and structurally related opioids.. M3G and M6G formation kinetics from morphine were determined using microsomes from five human livers. Inhibition of glucuronide formation was investigated with eight inhibitors (100 microm) and the mechanism of inhibition determined for (R)- and (S)-methadone (70-500 microm) using three microsomal samples.. Glucuronide formation displayed single enzyme kinetics. The M3G Vmax (mean+/-SD) was 4.8-fold greater than M6G Vmax (555+/-110 vs. 115+/-19 nmol mg-1 protein h-1; P=0.006, mean of difference 439; 95% confidence interval 313, 565 nmol mg-1 protein h-1). Km values for M3G and M6G formation were not significantly different (1.12+/-0.37 vs. 1.11+/-0.31 mm; P=0.89, 0.02; -0.29, 0.32 mm). M3G and M6G formation was inhibited (P<0.01) with a significant increase in the M3G/M6G ratio (P<0.01) for all compounds tested. Detailed analysis with (R)- and (S)-methadone revealed noncompetitive inhibition with (R)-methadone Ki of 320+/-42 microm and 192+/-12 microm for M3G and M6G, respectively, and (S)-methadone Ki of 226+/-30 microm and 152+/-20 microm for M3G and M6G, respectively. Ki values for M3G inhibition were significantly greater than for M6G for (R)-methadone (P=0.017, 128; 55, 202 microm) and (S)-methadone (P=0.026, 75; 22, 128 microm).. Both methadone enantiomers noncompetitively inhibited the formation of morphine's primary metabolites, with greater inhibition of M6G formation compared with M3G. These findings indicate a mechanism for reduced morphine clearance in methadone-maintained patients and reduced relative formation of the opioid active M6G compared with M3G.

Topics: Alamethicin; Analgesics, Opioid; Dextropropoxyphene; Humans; Ionophores; Methadone; Methadyl Acetate; Microsomes, Liver; Morphine Derivatives

A fully validated liquid chromatographic procedure coupled with electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) is presented for quantitative determination of the opioids buprenorphine, codeine, fentanyl, hydromorphone, methadone, morphine, oxycodone, oxymorphone, piritramide, tilidine, and tramadol together with their metabolites bisnortilidine, morphine-glucuronides, norfentanyl, and nortilidine in blood plasma after an automatically performed solid-phase extraction (SPE). Separation was achieved in 35 min on a Phenomenex C12 MAX-RP column (4 microm, 150 x 2 mm) using a gradient of ammonium formiate buffer (pH 3.5) and acetonitrile. The validation data were within the required limits. The assay was successfully applied to authentic plasma samples, allowing confirmation of the diagnosis of overdose situations as well as monitoring of patients' compliance, especially in patients under palliative care.

Topics: Analgesics, Opioid; Chromatography, Liquid; Fentanyl; Humans; Morphine Derivatives; Palliative Care; Patient Compliance; Spectrometry, Mass, Electrospray Ionization; Tilidine

Glucuronidation of morphine in humans is predominantly catalyzed by UDP-glucuronosyltransferase 2B7 (UGT2B7). Since our recent research suggested that cytochrome P450s (P450s) interact with UGT2B7 to affect its function [Takeda S et al. (2005) Mol Pharmacol 67:665-672], P450 inhibitors are expected to modulate UGT2B7-catalyzed activity. To address this issue, we investigated the effects of P450 inhibitors (cimetidine, sulfaphenazole, erythromycin, nifedipine, and ketoconazole) on the UGT2B7-catalyzed formation of morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G). Among the inhibitors tested, ketoconazole was the most potent inhibitor of both M-3-G and M-6-G formation by human liver microsomes. The others were less effective except that nifedipine exhibited an inhibitory effect on M-6-G formation comparable to that by ketoconazole. Neither addition of NADPH nor solubilization of liver microsomes affected the ability of ketoconazole to inhibit morphine glucuronidation. In addition, ketoconazole had an ability to inhibit morphine UGT activity of recombinant UGT2B7 freed from P450. Kinetic analysis suggested that the ketoconazole-produced inhibition of morphine glucuronidation involves a mixed-type mechanism. Codeine potentiated inhibition of morphine glucuronidation by ketoconazole. In contrast, addition of another substrate, testosterone, showed no or a minor effect on ketoconazole-produced inhibition of morphine UGT. These results suggest that 1) metabolism of ketoconazole by P450 is not required for inhibition of UGT2B7-catalyzed morphine glucuronidation; and 2) this drug exerts its inhibitory effect on morphine UGT by novel mechanisms involving competitive and noncompetitive inhibition.

Topics: Analgesics, Opioid; Cytochrome P-450 Enzyme Inhibitors; Enzyme Inhibitors; Glucuronosyltransferase; Humans; In Vitro Techniques; Ketoconazole; Microsomes, Liver; Morphine; Morphine Derivatives

To examine morphine metabolite serum concentrations in neonates undergoing venoarterial extra corporeal membrane oxygenation (ECMO) and to quantify clearance differences between these neonates and those subjected to noncardiac major surgery.. This was an observational study in level III referral centre. Fourteen neonates (< 7 days old) undergoing ECMO were included. Morphine and concomitant medications were given by protocol, adapted to the clinical conditions of the neonates. Pharmacokinetic findings were compared with those from a previous study in infants after noncardiac major surgery. Nonlinear mixed-effect modelling was used. Parameter estimates were standardised to a 70 kg person using allometric modeling. Morphine-3-glucuronide (M3G) was the predominant metabolite. Formation clearance to M3G at the start of ECMO on day 1 was lower than those in postoperative children, but matured more rapidly. After 10 days formation clearances of M3G in neonates on ECMO equalled those of postoperative children. Higher ECMO flows were associated with reduced formation clearances. Elimination clearances of M3G, but not morphine-6-glucuronide (M6G), were lower in the ECMO neonates; this was attributable to reduced renal clearance. These elimination clearances were correlated positively with ECMO flow and negatively with dopamine dose. Haemofiltration cleared M3G and M6G, but not morphine.. Formation clearance to M3G, the predominant metabolite, is reduced during the first 10 days of ECMO. Elimination clearance of M3G and M6G is related to creatinine clearance. ECMO flow had a small effect on metabolite clearance. Higher flows were associated with decreased formation clearances, possibly reflecting illness severity. Dopamine dose reflected decreased renal clearance.

Topics: Adult; Algorithms; Analgesics, Opioid; Bayes Theorem; Biotransformation; Cohort Studies; Extracorporeal Membrane Oxygenation; Female; Humans; Infant, Newborn; Male; Morphine; Morphine Derivatives; Population; Postoperative Period; Vecuronium Bromide

A simultaneous determination of morphine (M) and its two metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), by HPLC in the serum of oncological patients is described. The compounds are extracted from the serum by means of Chromabond C18--EC solid-phase-extraction cartridges, separated on a Symmetry C18 analytical column (150 x 4.9 mm, 5 microm) and detected by a UV detector at 210 nm. The mobile phase consisted of 8% acetonitrile in water, 30 mmol/l phosphate buffer (pH 3) and 1 mmol/l octane sulfonic acid as the ion pairing agent; its flow-rate was 0.8 ml/min. Under these conditions, the detection limits were 10 ng/ml, 60 ng/ml and 90 ng/ml for M, M3G, and M6G, respectively. This paper concerns blood serum concentration levels of M, M3G and M6G in oncological patients, their ratios and their role in pain resistance.

Topics: Adult; Aged; Analgesics, Opioid; Biotransformation; Chromatography, High Pressure Liquid; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain, Intractable; Sex Characteristics; Spectrophotometry, Ultraviolet

Morphine-6-glucuronide (M6G), an active metabolite of morphine has been shown to produce analgesia and fewer side effects than morphine, and the introduction of M6G as a new drug for treatment of postoperative pain is planned in 2007. Following morphine intake in humans, the metabolites morphine-3-glucuronide (M3G) and M6G are present in substantial concentrations and for longer periods than the parent drug. The possible reward effects of the morphine glucuronides have previously not been well studied. In the present study, conditioned place preference (CPP) was recorded after conditioning with subcutaneous injections of 5, 10, 20, 30 or 50 micromol/kg morphine or M6G, or 240 or 500 micromol/kg M3G in C57BL/6J-Bom mice, using a biased two compartment ("closed" and "open") counterbalanced paradigm. CPP was induced after treatment with both morphine and M6G with dose dependent increase up to 30 micromol/kg after treatment in the "closed" compartment. No dose response was observed in the "open" compartment, with maximal CPP after 10 micromol/kg morphine or M6G. M3G caused a tendency of condition place aversion (CPA), although not statistically significant. In the present study morphine and M6G demonstrated comparable reward effects, at doses that differed depending on which compartment the mice were conditioned in. M3G showed a tendency to exhibit aversive properties.

Topics: Analgesics, Opioid; Analysis of Variance; Animals; Conditioning, Operant; Male; Mice; Mice, Inbred C57BL; Morphine; Morphine Derivatives; Motor Activity; Seizures

To evaluate the relationship between major heroin metabolites (morphine, morphine-6-glucoronide), pattern of drug use, and late impairment of psychomotor functions.. From the database of the Norwegian Institute of Public Health, Oslo, blood morphine concentration in samples from heroin users (n=70) containing only morphine were correlated with results of the clinical test for impairment (CTI). For comparison, test results were explored in individuals without any positive analytical finding in blood samples (n=79) selected from the same database.. In the "no drug" cases, 86% were judged as not impaired and 14% as impaired. In the morphine only cases, 20% were judged as not impaired, and 80% as impaired. Both daily users and non-daily users had the same proportion of impaired cases. Median blood morphine concentration (M) was 0.09 micromol/l in the "not impaired" group and 0.15 micromol/l in the "impaired" group (P=0.067). For morphine-6-glucuronide (M6G), the median blood concentration was 0.09 micromol/l in the "not impaired" group and 0.14 micromol/l in the "impaired" group (P=0.030). A significant correlation between concentration quartiles and number of cases determined as "impaired" was found for M6G (P=0.018) and for the sum M+M6G (P=0.013).. In our population of heroin-drugged drivers, blood concentrations of M6G and the sum M+M6G appeared to have concentration-dependent effects on the CNS that may lead to impairment as judged from a CTI. Variations in pattern of use did not seem to have any bearing on the judgement of impairment.

Topics: Adult; Automobile Driving; Cognition; Female; Heroin Dependence; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Narcotics; Psychomotor Performance; Retrospective Studies; Substance Abuse Detection; Time Factors

A new immunoaffinity solid phase extraction of morphine and its phase II metabolites, morphine-3-beta-D-glucuronide and morphine-6-beta-D-glucuronide is described. An immunoadsorber was applied which was created for the first time by the immobilisation of specific antibodies (polyclonal, host: rabbit) by the sol-gel method. The extraction method in combination with high performance liquid chromatography-fluorescence determination has been validated and shown to be applicable to blood samples of heroin victims in a low concentration range. Blood extracts were essentially free of interfering matrix components when compared to C8-extracts. Additionally, a novel, sensitive and selective detection system for wavelength-resolved analysis of laser-induced fluorescence coupled to HPLC was developed. The analytes were excited with a frequency tripled Ti:Sa laser (lambda=244 nm quasi cw). The total emission spectrum was recorded with a detection system consisting of an imaging spectrograph and a back-illuminated CCD camera. This technique of detection, combined with an extended optical path (at least 6 mm could be illuminated by the laser), resulted in an optimal fluorescence intensity of the analytes. The method permitted the analysis of morphine, morphine-3-beta-D-glucuronide and morphine-6-beta-D-glucuronide in a low concentration range and could be applied to a complex matrix such as postmortem blood samples because analyte peaks could be discriminated from matrix peaks by their characteristic emission spectra.

Topics: Chromatography, High Pressure Liquid; Fluorescence; Forensic Medicine; Humans; Lasers; Morphine; Morphine Derivatives; Narcotics

Glucuronidation is a major detoxification pathway for endogenous and exogenous compounds in mammals that results in the intracellular formation of polar metabolites, requiring specialized transporters to cross biological membranes. By using morphine as a model aglycone, we demonstrate that multidrug resistance protein 3 (MRP3/ABCC3), a protein present in the basolateral membrane of polarized cells, transports morphine-3-glucuronide (M3G) and morphine-6-glucuronide in vitro. Mrp3(-/-) mice are unable to excrete M3G from the liver into the bloodstream, the major hepatic elimination route for this drug. This results in increased levels of M3G in liver and bile, a 50-fold reduction in the plasma levels of M3G, and in a major shift in the main disposition route for morphine and M3G, predominantly via the urine in WT mice but via the feces in Mrp3(-/-) mice. The pharamacokinetics of injected morphine-glucuronides are altered as well in the absence of Mrp3, and this results in a decreased antinociceptive potency of injected morphine-6-glucuronide.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B; ATP-Binding Cassette Transporters; Bile; Cell Line; Glucuronosyltransferase; Humans; Liver; Mice; Mice, Knockout; Morphine; Morphine Derivatives; Pain Measurement; Protein Transport; Spodoptera; Tissue Distribution; Transport Vesicles

In all age groups, the use of opioids to treat chronic pain conditions has increased, yet the impact of age on opioid tolerance development has not been comprehensively addressed. In this study, we investigated age-related differences in morphine tolerance development in rats. Rats aged 3 wk, 3 mo, 6 mo, and 1 yr were used in the study. Morphine (8 mg/kg) was injected subcutaneously twice each day and its analgesic effect assessed by the change in tail-flick latency using a thermal stimulus 5 min before and 30 min after dosing. Tolerance was defined as a 75% reduction in morphine-induced analgesia compared to Day 1. Rats aged 3 wk, 3 mo, 6 mo, and 1 yr developed tolerance on the 4th, 10th, 14th, and 22nd days of morphine treatment, respectively. Plasma levels of morphine and its metabolites showed that pharmacokinetic differences among the groups did not correlate with the differences in tolerance development. This study demonstrates that morphine tolerance occurs more rapidly in younger rats than older rats and is unlikely to be the result of differences in drug metabolism or clearance. Aging may impact molecular processes involved in tolerance development and provide insight into novel therapeutic targets to delay opioid tolerance development.

Topics: Aging; Analgesics, Opioid; Animals; Chromatography, High Pressure Liquid; Drug Tolerance; Male; Mass Spectrometry; Morphine; Morphine Derivatives; Pain Measurement; Rats; Rats, Sprague-Dawley; Reaction Time

Heroin is rapidly metabolized to morphine that in turn is transformed in morphine-3-glucuronide (M3G), an inactive metabolite, and morphine-6-glucuronide (M6G), a potent mu-opioid receptor (MOR) agonist. We have found that heroin addicts exhibit higher M6G/M3G ratios relative to morphine-treated control subjects. We have also shown that heroin-treated rats exhibit measurable levels of M6G (which is usually undetectable in this species) and reduced levels of M3G.. We investigated the role of MOR in these effects of heroin, by examining the effects of methadone, a MOR agonist, and of naltrexone, a MOR antagonist, on morphine glucuronidation. We also investigated the effects of alcohol, which is known to alter drug metabolism and is frequently coabused by heroin addicts.. Morphine glucuronidation was studied in liver microsomes obtained from rats exposed daily for 10 days to saline, heroin (10 mg/kg, i.p.), naltrexone (20-40 mg/kg, i.p.), heroin + naltrexone (10 mg/kg+20-40 mg/kg, i.p.), methadone (5-20 mg/kg, i.p.), or 10% ethanol.. Heroin induced the synthesis of M6G and decreased the synthesis of M3G. Naltrexone exhibited intrinsic modulatory activity on morphine glucuronidation, increasing the synthesis of M3G via a low-affinity/high-capacity reaction characterized by positive cooperativity. The rate of M3G synthesis in the heroin + naltrexone groups was not different from that of the naltrexone groups. Methadone and ethanol induced a modest increase in M3G synthesis and had no effect on M6G synthesis.. The effects of heroin on morphine glucuronidation are not shared by methadone or alcohol (two drugs that figure prominently in the natural history of heroin addiction) and do not appear to depend on the activation of MOR.

Topics: Animals; Ethanol; Heroin; Heroin Dependence; Male; Methadone; Microsomes, Liver; Morphine; Morphine Derivatives; Naltrexone; Rats; Rats, Sprague-Dawley; Receptors, Opioid, mu

A sensitive and reproducible method for the determination of morphine and the metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) was developed. The method was validated for perfusion fluid used in microdialysis as well as for sheep and human plasma. A C18 guard column was used to desalt the samples before analytical separation on a ZIC HILIC (hydrophilic interaction chromatography) column and detection with tandem mass spectrometry (MS/MS). The mobile phases were 0.05% trifluoroacetic acid (TFA) for desalting and acetonitrile/5 mM ammonium acetate (70:30) for separation. Microdialysis samples (5 microL) were directly injected onto the system. The lower limits of quantification (LLOQ) for morphine, M3G and M6G were 0.50, 0.22 and 0.55 ng/mL, respectively, and the method was linear from LLOQ to 200 ng/mL. For plasma, a volume of 100 microL was precipitated with acetonitrile containing internal standards (deuterated morphine and metabolites). The supernatant was evaporated and reconstituted in 0.05% TFA before the desalting process. The LLOQs for sheep plasma were 2.0 and 3.1 ng/mL and the ranges were 2.0-2000 and 3.1-3100 ng/mL for morphine and M3G, respectively. For human plasma, the LLOQs were 0.78, 1.49 and 0.53 ng/mL and the ranges were 0.78-500, 1.49-1000 and 0.53-500 ng/mL for morphine, M3G and M6G, respectively.

Topics: Central Nervous System Stimulants; Chromatography, High Pressure Liquid; Humans; Microdialysis; Morphine; Morphine Derivatives; Spectrometry, Mass, Electrospray Ionization

A liquid chromatographic-electrospray ionization-tandem mass spectrometric method for the quantification of the opiates morphine, codeine, and their metabolites morphine-3-beta-D-glucuronide (M-3-G), morphine-6-beta-D-glucuronide (M-6-G) and codeine-6-beta-D-glucuronide (C-6-G) in human urine has been developed and validated. Identification and quantification were based on the following transitions: 286 to 201 and 229 for morphine, 300 to 215 and 243 for codeine, 462 to 286 [corrected] for M-3-G, 462 to 286 for M-6-G, and 476 to 300 for C-6-G. Calibration by linear regression analysis utilized deuterated internal standards and a weighting factor of 1/X. The method was accurate and precise across a linear dynamic range of 25.0 to 4000.0 ng/ml. Pretreatment of urine specimens using solid phase extraction was sufficient to limit matrix suppression to less than 40% for all five analytes. The method proved to be suitable for the quantification of morphine, codeine, and their metabolites in urine specimens collected from opioid-dependent participants enrolled in a methadone maintenance program.

Topics: Calibration; Chromatography, Liquid; Codeine; Humans; Morphine; Morphine Derivatives; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization

In patients with pain of malignant origin morphine may be administered in high and often increasing doses during extended periods of time. In patients with chronic pain of non-malignant origin morphine may be an important remedy, and in these cases the goal is to keep the morphine dose stable. The pharmacokinetic as well as the pharmacodynamic consequences of long-term morphine treatment with special reference to the two most important metabolites of morphine morphine-6-glucuronide (M-6-G) and morphine-3-glucuronide (M-3-G) remain to be settled.. Assessments for pain, sedation and other morphine induced side effects were made several times for 19 cancer patients treated with changing doses of oral sustained release (SR) morphine and twice for 17 non-cancer patients treated with stable doses of SR morphine. Blood samples were obtained simultaneously and analysed for contents of morphine, M-3-G and M-6-G by high-performance liquid chromatography (HPLC).. Significant correlations were found between the daily dose of SR morphine and plasma morphine (r = 0.469, p < 0.01), plasma M-6-G (r = 0.677, p < 0.01), and plasma M-3-G ((r = 0.827, p < 0.01), in the cancer patient group, but only between the daily dose of SR morphine and plasma M-3-G (0.662, p < 0.01) and plasma M-6-G (0.571, p < 0.01) in the non-cancer patient group. Normalised M-3-G/M and M-6-G/M ratios for the cancer patient group were independent of duration of treatment and daily dose of SR morphine. Likewise in the non-cancer patient group duration of treatment did not influence the metabolite ratios. Correlations between pain score and plasma morphine, M-6-G and M-6-G/M were weak in the cancer patient as well as in the non-cancer patient group making it impossible to draw any conclusion regarding the potential contributory analgesic effect of M-6-G. Dryness of the mouth was the most frequent adverse effect reported in the non-cancer as well as the cancer patient group. In the latter group patients complaining of dryness of the mouth had significantly higher plasma morphine and M-6-G concentrations than patients who did not suffer from this side effect. This difference persisted (or was close to significance) when excluding patients receiving antidepressants.. In the cancer patient group neither dose nor treatment period seems to influence morphine glucuronidation. Likewise in the non-cancer patient group receiving stable doses of morphine duration of treatment does not seem to influence morphine glucuronidation. Dryness of the mouth was positively correlated to high plasma concentrations of morphine and M-6-G.

Topics: Adult; Aged; Analgesics, Opioid; Chronic Disease; Dose-Response Relationship, Drug; Drug Administration Routes; Drug Administration Schedule; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Pain Measurement; Salivary Glands; Xerostomia

A specific and simultaneous assay of morphine, morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G) in monkey and dog plasma has been developed. These methods are based on rapid isolation using solid phase extraction cartridge, and high-performance liquid chromatography (HPLC)-electrospray ionization (ESI)-tandem mass spectrometric (MSMS) detection. Analytes were separated on a semi-micro ODS column in acetonitrile-formic (or acetic) acid mixed solution. The selected reaction monitoring for assay in monkey and dog plasma, as precursor-->product ion combinations of m/z 286-->286 for morphine, m/z 462-->286 for glucuronides and m/z 312-->312 for internal standard (IS, nalorphine) were used. The linearity of morphine, M-3-G and M-6-G was confirmed in the concentration range of 0.5-50, 25-2500, 2.5-250 ng/ml in monkey plasma, 0.5-100, 25-5000, 2.5-500 ng/ml in dog plasma, respectively. The precision of this assay method, expressed as CV, was less than 15% over the entire concentration range with adequate assay accuracy. Therefore, the HPLC-ESI-MSMS method is useful for the determination of morphine, M-3-G and M-6-G with sufficient sensitivity and specificity in pharmacokinetic studies.

Topics: Animals; Chromatography, High Pressure Liquid; Dogs; Haplorhini; Morphine; Morphine Derivatives; Spectrometry, Mass, Electrospray Ionization

The feasibility of drug monitoring of serum concentrations of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) during chronic morphine therapy is not established. One important factor relevant to drug monitoring is to what extent morphine, M6G and M3G serum concentrations fluctuate during stable morphine treatment.. We included twenty-nine patients admitted to a palliative care unit receiving oral morphine (n = 19) or continuous subcutaneous (sc) morphine infusions (n = 10). Serum concentrations of morphine, M6G and M3G were obtained at the same time on four consecutive days. If readmitted, the patients were followed for another trial period. Day-to-day variations in serum concentrations and ratios were determined by estimating the percent coefficient of variation (CV = (mean/SD) x100).. The patients' median morphine doses were 90 (range; 20-1460) mg/24 h and 135 (range; 30-440) mg/24 h during oral and sc administration, respectively. Intraindividual fluctuations of serum concentrations estimated by median coefficients of day-to-day variation were in the oral group for morphine 46%, for M6G 25% and for M3G 18%. The median coefficients of variation were lower in patients receiving continuous sc morphine infusions (morphine 10%, M6G 13%, M3G 9%).. These findings indicate that serum concentrations of morphine and morphine metabolites fluctuate. The fluctuations found in our study are not explained by changes in morphine doses, administration of other drugs or by time for collection of blood samples. As expected the day-to-day variation was lower in patients receiving continuous sc morphine infusions compared with patients receiving oral morphine.

Topics: Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Dose-Response Relationship, Drug; Drug Monitoring; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Palliative Care; Prospective Studies

Dispositions for genes encoding opioid receptors may explain some variability in morphine efficacy. Experimental studies show that morphine and morphine-6-glucuronide are less effective in individuals carrying variant alleles caused by the 118 A > G polymorphism in the mu-opioid receptor gene (OPRM1). The purpose of the study was to investigate whether this and other genetic polymorphisms in OPRM1 influence the efficacy of morphine in cancer pain patients.. We screened 207 cancer pain patients on oral morphine treatment for four frequent OPRM1 gene polymorphisms. The polymorphisms were the -172 G > T polymorphism in the 5'untranslated region of exon 1, the 118 A > G polymorphism in exon 1, and the IVS2 + 31 G > A and IVS2 + 691 G > C polymorphisms, both in intron 2. Ninety-nine patients with adequately controlled pain were included in an analysis comparing morphine doses and serum concentrations of morphine and morphine metabolites in the different genotypes for the OPRM1 polymorphisms.. No differences related to the -172 G > T, the IVS2 + 31 G > A and the IVS2 + 691 G > C polymorphisms were observed. Patients homozygous for the variant G allele of the 118 A > G polymorphism (n = 4) needed more morphine to achieve pain control, compared to heterozygous (n = 17) and homozygous wild-type (n = 78) individuals. This difference was not explained by other factors such as duration of morphine treatment, performance status, time since diagnosis, time until death, or adverse symptoms.. Patients homozygous for the 118 G allele of the mu-opioid receptor need higher morphine doses to achieve pain control. Thus, genetic variation at the gene encoding the mu-opioid receptor contributes to variability in patients' responses to morphine.

Topics: Aged; Alleles; Analgesics, Opioid; Dose-Response Relationship, Drug; Female; Genetic Testing; Genotype; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain Measurement; Pain, Intractable; Polymorphism, Genetic; Quality of Life; Receptors, Opioid, mu; Reverse Transcriptase Polymerase Chain Reaction

Morphine, the recommended drug for the management of moderate to severe cancer pain, is metabolized predominantly to the glucuronides morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G). The quantitative clinical importance of these metabolites following the administration of oral morphine is unclear. This study investigates the relationship between plasma concentrations of morphine (M), M6G, M3G and clinical effects in patients receiving sustained release oral morphine for cancer-related pain. Peak and trough plasma concentrations of morphine and its metabolites were determined by high-performance liquid chromatography (HPLC). At corresponding time points, pain [Visual Analogue Scales (VAS), Verbal Rating Scales (VRS), Pain Relief Scores (PRS)] and toxicity (VAS and VRS) were assessed. Renal and liver function tests were performed. Forty-six patients were included in the study. There was a significant correlation between dose and both peak and trough plasma M, M6G and M3G (r > 0.60, P < 0.001 for each). Differences between peak and trough M, M6G, M3G, M+M6G, M6G:M, M3G:M and M3G:M6G were all significant (P < 0.001 for each). Pain was generally well controlled in the group, with a median VAS of 15 mm at the peak blood sampling time point. The differences between peak and trough values for VAS pain, VAS nausea and VAS drowsiness were not statistically significant (P = 0.078, 0.45 and 0.099, respectively). There were no differences in peak or trough morphine and metabolite concentrations or ratios between patients with low (< median) or high pain scores. Similarly, there was no significant relationship between high and low plasma concentrations and clinical effect. This study did not identify a simple relationship between plasma concentrations of morphine, morphine metabolites or metabolite ratios and clinical effects in patients with cancer and pain who were receiving chronic oral morphine therapy. Although overall pain control was good, there was marked interpatient variability in the dose of morphine and the plasma concentrations necessary to achieve this degree of analgesia.

Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Central Nervous System Stimulants; Dose-Response Relationship, Drug; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Pain Measurement

In the body, heroin is rapidly transformed to 6-acetylmorphine (6-AM) and then to morphine, that in turn is mainly metabolized to morphine-3-glucuronide (M3G) and, at lesser extent, to morphine-6-glucuronide (M6G). Unlike M3G, M6G is a potent opioid agonist. Intravenous heroin abusers (IHU) are exposed to a wide array of drugs and contaminants that might affect glucuronidation.. We assessed plasma and urine concentrations of M3G and M6G in four groups of subjects: the first two included long-term IHU either exposed to street heroin ( n=8) or receiving a single IV injection of morphine ( n=4), while the other two groups included non-IHU patients receiving acute IV ( n=8) or chronic oral ( n=6) administrations of morphine.. After solid phase extraction plasma and urine concentrations of morphine metabolites were determined by HPLC analyses.. M3G accounted for the greater part of morphine glucuronides detected in body fluids of non-IHU patients treated with morphine. This pattern of metabolism remained stable across 15 days of oral administration of incremental doses of morphine. In contrast, the two groups of IHU (street heroin taking or morphine-treated subjects) showed a reduction of blood and urine M3G concentrations in favor of M6G. Consequently, M6G/M3G ratio was significantly higher in the two IHU groups in comparison with the non-IHU groups.. Chronic exposure to street heroin causes a relative increase in concentrations of the active metabolite, M6G. Since the pattern of M6G action seems closer to heroin than to morphine, the increased synthesis of M6G observed in IHU may prolong the narrow window of heroin effects.

Topics: Adult; Aged; Analgesics, Opioid; Analysis of Variance; Chromatography, High Pressure Liquid; Drug Administration Schedule; Female; Heroin; Heroin Dependence; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Narcotics; Time Factors

Morphine elimination involves UDP-glucuronosyltransferase (UGT) catalyzed conjugation with glucuronic acid to form morphine 3- and 6-glucuronides (M3G and M6G, respectively). It has been proposed that UGT2B7 is the major enzyme involved in these reactions, but there is evidence to suggest that other isoforms also catalyze morphine glucuronidation in man. Thus, we have characterized the selectivity and kinetics of M3G and M6G formation by recombinant human UGTs. UGT 1A1, 1A3, 1A6, 1A8, 1A9, 1A10, and 2B7 all catalyzed M3G formation, but only UGT2B7 formed M6G. The kinetics of M3G formation by the UGT1A family isoforms was consistent with a single enzyme Michaelis-Menten model, with apparent Km values ranging from 2.6 to 37.4 mM. In contrast, M3G and M6G formation by UGT2B7 exhibited atypical kinetics. The atypical kinetics may be described by a model with high- and low-affinity Km values (0.42 and 8.3 mM for M3G, and 0.97 and 7.4 mM for M6G) from fitting to a biphasic Michaelis-Menten model. However, a multisite model with an interaction between two identical binding sites in a negative cooperative manner provides a more realistic approach to modeling these data. According to this model, the respective binding affinities (Ks) for M3G and M6G were 1.76 and 1.41 mM, respectively. These data suggest that M6G formation may be used as a selective probe for UGT2B7 activity, and morphine glucuronidation by UGT2B7 appears to involve the simultaneous binding of two substrate molecules, highlighting the need for careful analysis of morphine glucuronidation kinetics in vitro.

Topics: Cell Line; Glucuronosyltransferase; Humans; Isoenzymes; Kinetics; Microsomes, Liver; Morphine Derivatives; Substrate Specificity

After absorption, heroin is transformed into mono-acetyl-morphine and then into morphine. Morphine, in turn, is metabolized to morphine-3-glucuronide (M3G), an inactive compound, and morphine-6-glucuronide (M6G), a potent opioid agonist. Thus, changes in the rate of formation of M6G may alter the pharmacological consequences of a treatment with heroin or morphine. In this study, we investigate the effect of repeated exposures (10 daily i.p. injections) to heroin, morphine, cadmium (which has been previously shown to inhibit M3G formation in vitro), or heroin + cadmium on morphine glucuronidation both in vivo and ex vivo (i.e., microsomal preparation obtained from rats treated in vivo). Repeated heroin (2.5, 5.0, and 10 mg/kg) increased plasma levels of M6G (which was undetectable in all other groups) and reduced those of M3G. Also, the microsomal preparations obtained from the liver of repeated heroin rats, when incubated with morphine, yielded significant amounts of M6G (which was undetectable in all other groups) and decreased levels of M3G relative to the control groups. These effects were reversible upon discontinuation of heroin administration. In contrast, repeated morphine (10, 20, and 40 mg/kg) only slightly reduced M3G formation at the dose of 40 mg/kg. Repeated cadmium (5, 15, and 45 microg/kg) reduced the rate of M3G formation without inducing M6G synthesis. The effects of the repeated coadministration of heroin (10 mg/kg) and cadmium (15 microg/kg) were virtually identical to those of repeated heroin alone. In summary, repeated exposure of rats to heroin can shift morphine glucuronidation toward the formation of the active metabolite M6G.

Topics: Analgesics, Opioid; Animals; Cadmium; Chromatography, High Pressure Liquid; Guinea Pigs; Heroin; Male; Microsomes, Liver; Morphine; Morphine Derivatives; Rats; Rats, Sprague-Dawley

This study was performed to assess the pharmacokinetics of morphine and its major metabolites after its rectal or colostomal administration in rectal-resected (ROP) or colostoma-constructed (SOP) rabbits, respectively. The pharmacokinetics of morphine, morphine-3-glucuronide (M3G), and M6G in normal rabbits appeared to be similar to those in human, judging from their plasma concentration-time profiles and the susceptibility of morphine to first-pass metabolism. In SOP, but not ROP, rabbits, the plasma concentrations of morphine, M3G and M6G were significantly increased compared with those in normal rabbits. The AUC of morphine and its metabolites, and the F value of the former in the SOP group were greater than those in the control group, while the elimination half-life (t(1/2)) values were comparable in the two groups. In addition, the disposition of morphine and its metabolites after intravenous (i.v.) administration to SOP rabbits was almost the same as that in normal rabbits, suggesting that an increase in the rate of absorption of morphine in SOP rabbits was not due to inflammation at the absorption site caused by operation, but probably due to its increased solubility in loose stools. Therefore, great attention should be paid when morphine suppositories are intracolostomally administered to colostoma-constructed patients.

Topics: Administration, Oral; Analgesics, Opioid; Animals; Biological Availability; Colostomy; Injections, Intravenous; Male; Models, Animal; Morphine; Morphine Derivatives; Rabbits; Suppositories

To provide additional pharmacokinetic evidence for the oral-to-parenteral relative potency ratio of 1:2 to 1:3 for chronic morphine use in a palliative care setting, we determined the plasma concentrations of morphine and its major metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), in hospitalized advanced cancer patients maintained on long-term oral or intravenous morphine. There were significant linear correlations between daily doses of morphine and plasma concentrations (molar base) of morphine, M3G and M6G for both routes of administration. The oral-to-intravenous relative ratios of the regression coefficients were 2.9 for morphine and 1.8 for morphine + M6G. The morphine kinetic variables were not significantly influenced by any hepato-renal biochemical markers. These results support the commonly used oral-to-intravenous relative potency ratio of 1:2 to 1:3 in patients with cancer pain receiving chronic morphine treatment.

Topics: Administration, Oral; Aged; Analgesics, Opioid; Chronic Disease; Dose-Response Relationship, Drug; Female; Humans; Infusions, Parenteral; Injections, Intravenous; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Palliative Care

The clinical importance of routine drug monitoring of serum concentrations of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) during chronic morphine therapy is not established. We measured morphine, M6G and M3G serum concentrations in cancer pain patients receiving oral (n = 263, median dose 80 mg/24 hours) or subcutaneous (sc) (n = 35, median dose 110 mg/24 hours) morphine. Regression analyses were performed to investigate if serum concentrations of morphine, M3G and M6G predicted pain intensity (Brief Pain Inventory), health-related quality-of-life variables (EORTC QLQ-C30) and cognitive function (Mini-Mental Score). Serum concentrations were also compared in patients categorized as morphine 'treatment successes' and 'treatment failures'. We observed that serum concentrations of morphine, M6G or M3G did not predict pain intensity, cognitive function, nausea or tiredness. 'Treatment failures' caused by nausea, tiredness, cognitive failure or constipation did not have statistically significant different morphine, M6G and M3G serum concentrations than patients classified as 'treatment successes'. In conclusion, this study did not observe any concentration-effect relationships of morphine, M3G or M6G with pain intensity, nausea, constipation, tiredness or cognitive failure in blood samples obtained during routine clinical drug monitoring in cancer patients. This result suggests that therapeutic drug monitoring as a routine tool during chronic morphine treatment has limited value for clinical decision making.

Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Cognition Disorders; Dose-Response Relationship, Drug; Drug Monitoring; Fatigue; Female; Humans; Infusions, Parenteral; Male; Middle Aged; Morphine; Morphine Derivatives; Nausea; Neoplasms; Pain; Pain Measurement; Palliative Care

Ultrafast liquid chromatography/tandem mass spectrometry (LC/MS/MS) bioanalysis was demonstrated with the use of packed silica columns operated under elevated flow rates. A special effort has been made to achieve ultrafast analysis without sacrificing chromatographic resolution. Two multiple analyte/metabolites assays, (1) morphine/morphine-6-glucuronide(M6G)/morphine-3-glucuronide(M3G) and (2) midazolam/1'-hydroxymidazolam/4-hydroxymidazolam, were used to demonstrate the speed, sensitivity, peak shape and separation of the ultrafast methods utilizing silica columns. In both methods adequate chromatographic separation was a necessity because quantitation results would be otherwise compromised due to cross interference between different selected reaction monitoring (SRM) transitions. Baseline resolutions between morphine, M6G and M3G in human plasma extracts were achieved within 30 s on a 50 x 3 mm Betasil silica column operated at 4 mL/min of isocratic acetonitrile/water mobile phase. The total injection-to-injection cycle time was 48 s with a simple, single-autosampler/single-column setup, when a Shimadzu SIL-HT autosampler was used. Baseline resolution between 1'-hydroxymidazolam and 4-hydroxymidalolam in monkey plasma extracts was achieved within 33 s using similar conditions. Due to the absence of carry-over in this case, no rinsing of the injection needle was necessary, resulting in a cycle time of only 39 s/sample. These ultrafast methods were successfully used to analyze extracted biological samples and proved to be reproducible, reliable and generated equivalent pharmaco-kinetic (PK) results to those obtained by regular flow LC/MS/MS analysis to support discovery PK studies.

Topics: Animals; Chromatography, Liquid; Humans; Macaca fascicularis; Midazolam; Morphine; Morphine Derivatives; Reproducibility of Results; Sensitivity and Specificity; Silicon Dioxide; Solvents; Spectrum Analysis

The main metabolites of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), have been considered to participate in some of the effects of morphine. There is limited knowledge of the pharmacokinetics and dynamics of morphine and the main metabolites in mice, but mice are widely used to study both the analgesic effects and the psychomotor effects of morphine. The present study aimed to explore pharmacokinetic differences between morphine and morphine-glucuronides in mice after different routes of administration, and to investigate how possible differences were reflected in locomotor activity, a measure of psychostimulant properties. Mice were given morphine, M3G or M6G by different routes of administration. Serum concentrations versus time curves, pharmacokinetic parameters and locomotor activity were determined. Intraperitoneal administration of morphine reduced the bioavailability compared to intravenous and subcutaneous administration, but not so for morphine-glucuronides. The two morphine-glucuronides had similar pharmacokinetics, but morphine demonstrated higher volume of distribution and clearance than morphine-glucuronides. The present results demonstrated no locomotor effect of M3G, but a serum concentration effect relationship for morphine and M6G. When serum concentrations and effect changes were followed over time, there was some right hand shifts with respect to locomotor activity, especially during the declining phase of the concentration curve and particularly for M6G.

Topics: Animals; Biological Availability; Male; Mice; Mice, Inbred C57BL; Morphine; Morphine Derivatives; Motor Activity

Concentrations in the cerebrospinal fluid (CSF) are a useful approximation to the effect site for drugs like morphine. However, CSF samples, are available only in rare circumstances. If they can be obtained they may provide important insights into the pharmacokinetics/pharmacodynamics of opioids.. Nine neurological and neurosurgical patients (age 19-69 years) received 0.5 mg kg-1 morphine sulphate pentahydrate as an intravenous infusion over 30 min. Plasma and CSF were collected for up to 48 h. Concentration time-course and interindividual variability of morphine (M), morphine-3-glucuronide (M3G) and morphine-6 glucuronide (M6G) were analysed using population pharmacokinetic modelling.. While morphine was rapidly cleared from plasma (total clearance = 1838 ml min-1 (95% CI 1668, 2001 ml min-1)) the glucuronide metabolites were eliminated more slowly (clearance M3G = 44.5 ml min-1 (35.1, 53.9 ml min-1), clearance M6G = 42.1 ml min-1 (36.4, 47.7 ml min-1)) and their clearance could be described as a function of creatinine clearance. The central volumes of distribution were estimated to be 12.7 l (11.1, 14.3 l) for morphine. Transfer from the central compartment into the CSF was also rapid for M and considerably slower for both glucuronide metabolites. Maximum concentrations were achieved after 102 min (M), 417 min (M3G) and 443 min (M6G). A P-glycoprotein exon 26 polymorphism previously found to be linked with transport activity could be involved in CSF accessibility, since the homozygous mutant genotype was associated (P < 0.001) with high maximum CSF concentrations of M but not M3G or M6G.. From the population pharmacokinetic model presented, CSF concentration profiles can be derived for M, M3G and M6G on the basis of dosing information and creatinine clearance without collecting CSF samples. Such profiles may then serve as the link between dose regimen and effect measurements in future clinical effect studies.

Topics: Adult; Aged; Central Nervous System Stimulants; Creatinine; Dose-Response Relationship, Drug; Female; Genes, MDR; Genotype; Humans; Infusions, Intravenous; Intracranial Hemorrhages; Male; Metabolic Clearance Rate; Middle Aged; Models, Biological; Morphine; Morphine Derivatives; Narcotics

A bioanalytical method using automated sample transferring, automated solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) was developed for morphine (MOR), and its metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in human plasma. Samples of 0.25 ml were transferred into 96-well plate using automatic liquid handler (Multiprobe II). Automated SPE was carried out on a 96-channel programmable liquid handling workstation (Quadra 96) using a C(18) sorbent. The extract was injected onto a silica column using an aqueous-organic mobile phase. The chromatographic run time was 3.5 min per injection, with retention times of 1.5, 2.0 and 2.6 min for MOR, M6G, and M3G, respectively. The detection was by monitoring MOR at m/z 286-->152, M6G and M3G at m/z 462-->286. The deuterated internal standards were monitored at m/z 289-->152 for MOR-d(3), and m/z 465-->289 for M6G-d(3) and M3G-d(3). The standard curve range was 0.5-50 ng ml(-1) for MOR, 1.0-100 ng ml(-1) for M6G, and 10-1000 ng ml(-1) for M3G. The inter-day precision and accuracy of the quality control samples were <8% relative standard deviation (RSD) and <7% relative error (RE) for MOR, <5% RSD and <2% RE for M6G, and <2% RSD and <4% RE for M3G.

Topics: Automation; Calibration; Chromatography, Liquid; Humans; Mass Spectrometry; Morphine; Morphine Derivatives; Quality Control; Reproducibility of Results

A cancer patient receiving long-term oral sustained-release morphine treatment and periodically presenting with unusually high plasma M3G/M6G ratios is described. We found the patient's formation of M6G more unstable and perhaps delayed compared to the formation of M3G. There is no apparent explanation for this phenomenon and the high M3G/M6G ratios had no implications for the patient's pain experience or side effects from the morphine treatment.

Topics: Analgesics, Opioid; Central Nervous System Stimulants; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Pain; Prostatic Neoplasms; Time Factors

A sensitive and specific method for the determination of morphine glucuronides in human plasma is presented. Morphine glucuronides, namely morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G), were extracted from plasma by solid-phase extraction on C(18) cartridges at pH 9.3 and derivatized to their pentafluorobenzyl ester trimethylsilyl ether derivatives. The compounds were measured by gas chromatography/negative ion chemical ionization mass spectrometry without any further purification. Using this detection mode, a diagnostic useful fragment ion at m/z 748 was obtained at high relative abundance for both target compounds. [(2)H(3)]-labeled morphine glucuronides were used as internal standards. Calibration graphs were calculated by polynomial fit within a range of 10-1280 and 15-1920 nmol l(-1) for the 6- and 3-glucuronide, respectively. At the limit of quantitation (LOQ), the inter-assay precision was 2.21% (M3G) and 2.23% (M6G) and the GC/MS assay variability was 1.8% (M3G) and 0.9% (M6G). The accuracy at the LOQ showed deviations of +4.92% (M3G) and +1.5% (M6G). The sample recovery after solid-phase extraction was 84.7% for both M3G and M6G. The method is rugged, rapid and robust and has been applied to the batch analysis of morphine glucuronides during pharmacokinetic profiling of the drugs.

Topics: Calibration; Central Nervous System Stimulants; Gas Chromatography-Mass Spectrometry; Humans; Morphine Derivatives; Reproducibility of Results; Sensitivity and Specificity

Morphine-6-glucuronide (M-6-G) and morphine-3-glucuronide (M-3-G) are the two most important metabolites of morphine. Both are pharmacologically active, however, with different effects. M-6-G has been demonstrated capable of inducing anti-nociception and sedation, and M-3-G may induce behavioural excitation and possibly antagonise anti-nociception. Their impact on pharmacodynamics in patients in long-term treatment with oral morphine remains to be settled.. Forty-two cancer patients treated with oral sustained-release (SR) morphine were assessed for pain, sedation and other side effects related to morphine treatment. Blood samples were analysed for morphine, M-3-G and M-6-G by high-performance liquid chromatography (HPLC).. Significant correlations were found between the daily dose of SR morphine and plasma morphine (M) (r = 0.535, P < 0.001), plasma M-6-G (r = 0.868, P < 0.001) and plasma M-3-G (r = 0.865, P < 0.001). There was no relationship between plasma morphine, M-6-G, M-6-G/M and pain and sedation scores. Seventy-nine percent of the patients suffered from dryness of the mouth, which was the most frequent side effect observed. Patients in this group had higher plasma morphine and M-6-G concentrations than patients who did not suffer from this side effect.. The plasma concentrations of morphine and its metabolites, M-3-G and M-6-G, are significantly correlated to the daily dose of SR morphine. Although M-6-G has analgesic properties, no associations were found between pain and plasma morphine and morphine metabolites. This may be due to the multitudinous factors affecting the dose-effect relationship. Patients with dryness of the mouth had higher concentrations of morphine and M-6-G than patients without this side effect.

Topics: Adult; Aged; Analgesics, Opioid; Delayed-Action Preparations; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain

A method is described for the rapid and automatic analysis of flexible molecular alignments using multidimensional scaling and a normalized scoring scheme. A projection scheme was devised to separate orientational and conformational effects. It is shown that the approach can be utilized for the identification of common binding orientations or to the study of differences in partioning behavior. It is suggested that the method can be employed as a novel approach exploring molecular similarity as a dynamic property, so that it includes aspects of motion (by way of mutual orientations), conformations and molecular properties.

Topics: Antiviral Agents; Binding Sites; Carbonic Anhydrases; Computer Simulation; Drug Design; Enzyme Inhibitors; GABA Antagonists; Isomerism; Ligands; Models, Molecular; Molecular Conformation; Molecular Structure; Morphine Derivatives; Permeability; Thermolysin

Pharmacokinetics of three morphine 3-esters-3-(2,2-dimethylvaleroyl) morphine (A), 3-(2-phenylbenzoyl) morphine (B), and 3-(2,2-diphenylpropionyl) morphine (C) was characterized after single oral administration in rabbits. Blood was sampled up to 24 h and cerebro-spinal fluid (CSF) was collected with the last blood sample. The concentration of the morphine 3-esters, morphine, morphine 3-glucuronide and morphine 6-glucuronide were determined in plasma and CSF using HPLC UV-detection. The morphine 3-esters were suggested to be a subject to marked presystemic elimination, since, in comparison to the administration of the un-esterified morphine, relatively low concentrations of morphine and morphine glucuronides were detected in plasma. The rate of disposition of morphine was dependent on the hydrolytic stability of the esters. The mean (+/- S.E.) plasma half-life of morphine was 0.9 +/- 0.2 h, 2.5 +/- 0.6 h and 3.5 +/- 3.5 h after the administration of A, B and C, respectively, compared to 0.9 +/- 0.2 h as estimated after the administration of non-esterified morphine. An analgesic effect will be achieved, since morphine was detected in CSF even 24 h after the application of the ester pro-drugs. It is concluded that esterification at the 3-position may be adapted to obtain sustained plasma levels of morphine.

Topics: Administration, Oral; Animals; Area Under Curve; Chinchilla; Half-Life; Male; Morphine; Morphine Derivatives; Rabbits

A reversed-phase high-performance liquid chromatographic method with coulometric and UV detection has been developed for the simultaneous determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide. The separation was carried out by using a Supelcosil LC-8 DB reversed-phase column and 0.1 M potassium dihydrogen phosphate (pH 2.5)--acetonitrile--methanol (94:5:1 v/v) containing 4 mM pentanesulfonic acid as the mobile phase. The compounds were determined simultaneously by coulometry for morphine and with UV detection for morphine-3-glucuronide and morphine-6-glucuronide. Morphine, morphine glucuronides and the internal standard were extracted from human plasma using Bond-Elut C18 (1 ml) solid-phase extraction cartridges. In the case of coulometric detection, the detection limit was 0.5 ng/ml for morphine; in the case of UV detection the detection limit was 10 ng/ml for morphine-3-glucuronide and for morphine-6-glucuronide, too.

Topics: Chromatography, High Pressure Liquid; Colorimetry; Humans; Morphine; Morphine Derivatives; Spectrophotometry, Ultraviolet; Therapeutic Equivalency

The simultaneous determination of morphine and the glucuronide metabolites [morphine-3-beta-D-glucuronide (M3G) and morphine-6-beta-D-glucuronide (M6G)] in rat hair and rat plasma was carried out using reversed-phase high-performance liquid chromatography (HPLC) coupled with electrospray ionization mass spectrometry (ESI-MS). The chromatographic separation of the analytes was achieved using a semi-micro-HPLC column (3 microm particle size; 100 x 2.0 mm id) by gradient elution with 50 mM ammonium acetate and acetonitrile as eluents. After separation, morphine and the glucuronides were determined by selected ion monitoring (SIM) of ESI-MS using the quasi-molecular ions [M + H]+ at m/z = 286 and 462, respectively. The calibration curves were linear between the concentration of the analytes and the deuterium-labelled morphine (M-d3) selected as internal standard. The method was applied for the determination of the incorporation of morphine and the glucuronides into the hair shafts and hair roots of Dark Agouti rats after single intraperitoneal administration of morphine hydrochloride. Plasma concentrations of morphine and glucuronides were simultaneously determined after administration. Morphine and M3G were detected in the hair shafts and the hair roots. The concentrations of M3G in the hair root were lower than those of morphine in all sampling periods. In contrast, M3G concentrations in plasma were relatively higher at each sampling time. Small quantities of M6G were also identified in the plasma up to 4 h after administration. The concentration difference between the hair root and plasma seems to be due to the incorporation ratio of morphine and glucuronide into hair. As M3G was also identified in the hair shaft 1 week after administration, the incorporation of glucuronide metabolites into hair is obvious. This is the first report of the identification of morphine glucuronide in hair samples without the use of acid hydrolysis or enzyme digestion.

Topics: Animals; Chromatography, High Pressure Liquid; Hair; Male; Morphine; Morphine Derivatives; Rats; Rats, Inbred Strains; Spectrometry, Mass, Electrospray Ionization

Using heterologous expression in Xenopus laevis oocytes, we compared the potencies of morphine, morphine-6beta-glucuronide (M6G), and morphine-3-glucuronide (M3G) for cloned human mu- (hMOR), kappa- (hKOR), and delta-opioid receptors (hDOR). Each receptor subtype was individually co-expressed with heteromultimeric G-protein coupled inwardly rectifying K(+) (GIRK) channels, consisting of GIRK1 and GIRK2 subunits, and RGS4, a regulator of G-protein signaling. The two-microelectrode voltage clamp technique was used to measure the opioid receptor-activated GIRK1/GIRK2 channel responses. Compared with morphine, M6G had higher potency at the hMOR, lower potency at the hKOR, and similar potency at the hDOR, while M3G showed a 1000-fold lower and non-selective potency via opioid receptors. In contrast to naloxone, M3G did not antagonize the effects of morphine at the hMOR. We also investigated whether Trp318 and His319 provide the molecular basis for mu/delta selectivity and mu/kappa selectivity of morphinan alkaloids by mutating these residues to their corresponding residues in kappa- and delta-opioid receptors. A single-point mutation (W318L) on hMOR completely conferred delta-like potency for morphine and M6G on the mutant mu-receptor. Double mutation at Trp318 and His319 positions (Trp318Y/His319Y) only partially conferred kappa-like potency for morphine and M6G; the decrease in potency for M6G was significantly larger than for morphine. The results of our study show that both M6G and M3G are opioid receptor agonists with different potencies and that the potency of morphinan receptor ligands can be changed by selective mutations of hMOR at the Trp318 and His319 positions.

Topics: Analgesics, Opioid; Animals; Humans; Morphine; Morphine Derivatives; Oocytes; Receptors, Opioid; Receptors, Opioid, delta; Receptors, Opioid, kappa; Receptors, Opioid, mu; Xenopus laevis

To investigate the effects of major thermal burn injury and continuous intravenous morphine infusion on the disposition of morphine and its glucuronidated metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) once a week for three weeks.. Five patients with major first-, second-, or third-degree burn injuries received long-term intravenous morphine infusion. The required dose varied greatly (from 4 to 39.5 mg/h). The steady-state concentrations of morphine, M3G, and M6G ranged from 20 to 452, 29 to 3436, and 20 to 1240 mumol/L, respectively. The systemic clearance (Cls) of morphine ranged from 14.8 to 40.3 mL/min/kg and did not change over time. The ratios of M6G and M3G to morphine were not affected by dose, even with the wide variation of intravenous dosage. Morphine kinetics appeared to be first-order. Mean recovery of morphine, M3G, and M6G in urine was 1.7 +/- 1.0%, 42.0 +/- 16.8%, and 11.8 +/- 3.2%, respectively, and renal clearance ranged from 8 to 64, 26 to 325, and 59 to 589 mL/min, respectively. Mean pain intensity ratings at rest remained low and stable (0.7 +/- 0.9 on day 7, 0.4 +/- 0.3 on day 14, 0 +/- 0 on day 21).. To our knowledge, this is the first published report describing morphine, M3G, and M6G disposition in patients with major thermal burn injury. The Cls of morphine is similar to that observed in other patient populations and healthy subjects, suggesting that the presence of major burn injuries or a continuous morphine infusion over a three-week period may not contribute significantly to the variability among individuals. In these cases, the renal clearance of morphine and its glucuronides was within the range of values reported for other populations of patients and healthy subjects. Recovery of morphine and its glucuronides in urine was also similar to that in healthy individuals.. These cases suggest that the effects of major burn injuries and of long-term intravenous infusion of morphine did not seem to modify morphine, M3G, and M6G disposition. Among patients with burn injuries, the severity of burns of duration of administration are not a cause of nonlinear kinetic of morphine or of morphine resistance. The morphine infusion rate was substantially variable and not directly related to its clearance, suggesting that monitoring of morphine should be focused on the clinical response.

Topics: Adult; Analgesics, Opioid; Burns; Chromatography, High Pressure Liquid; Female; Humans; Infusions, Intravenous; Liver Function Tests; Male; Metabolic Clearance Rate; Middle Aged; Morphine; Morphine Derivatives

Morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) are active metabolites of morphine. The effects of M3G and M6G on the opioid receptor transduction system has not yet been fully elucidated. Formation of cAMP after treatment with various doses of morphine, M3G, and M6G was studied. M6G and morphine, but not M3G, showed a dose dependent inhibition of cAMP accumulation. Naloxone blocked the inhibitory effect of M6G, M3G, and morphine. Pretreatment with M3G did not change the effects of morphine and M6G. The G-protein inhibitor PTX, prevented morphine, M3G, and M6G effects on cAMP. M3G and M6G vary in their ability to interact with the opioid receptor effector system. Inhibition of cAMP evoked by activation of opioid receptors and inhibitory G-proteins may play a role in the actions of M6G and M3G.

Topics: Alprostadil; Cyclic AMP; Dose-Response Relationship, Drug; Humans; Morphine Derivatives; Naloxone; Receptors, Opioid; Tumor Cells, Cultured; Virulence Factors, Bordetella

Morphine-3- and morphine-6-glucuronide are morphine's major metabolites. As morphine-6-glucuronide produces stronger analgesia than morphine, we investigated the effects of acute and chronic morphine glucuronides on adenylyl cyclase (AC) activity. Using COS-7 cells cotransfected with representatives of the nine cloned AC isozymes, we show that AC-I and V are inhibited by acute morphine and morphine-6-glucuronide, and undergo superactivation upon chronic exposure, while AC-II is stimulated by acute and inhibited by chronic treatment. Morphine-3-glucuronide had no effect. The weak opiate agonists codeine and dihydrocodeine are also addictive. These opiates, in contrast to their 3-O-demethylated metabolites morphine and dihydromorphine (formed by cytochrome P450 2D6), demonstrated neither acute inhibition nor chronic-induced superactivation. These results suggest that metabolites of morphine (morphine-6-glucuronide) and codeine/dihydrocodeine (morphine/dihydromorphine) may contribute to the development of opiate addiction.

Topics: Adenylyl Cyclase Inhibitors; Adenylyl Cyclases; Animals; CHO Cells; Codeine; Cricetinae; Dihydromorphine; Dose-Response Relationship, Drug; Enzyme Activation; Isoenzymes; Morphine; Morphine Derivatives; Opioid-Related Disorders; Receptors, Opioid, mu; Thyrotropin; Transfection

Morphine-6-glucuronide (M6G), a major metabolite of morphine with agonist opioid-receptor activity, was reported to be a substrate of P-glycoprotein (P-gp). Inhibition of P-gp may thus result in higher brain uptake of M6G. The goal of this observer-blinded, placebo controlled study, was to compare the antinociceptive effects of M6G in homozygous P-gp knockout (mdr1a(-/-)) and wildtype (mdr1a(+/+)) mice. M6G was injected intraperitoneally as a single dose of 0, 0.5, 1, 2.5, 5, and 10 mg/kg. Eight P-gp knockout and eight wildtype mice were studied per dose. A hot plate test was performed before and 5, 15, 30, 60, 90, 120, and 150 min after M6G administration. Plasma-concentrations of M6G, morphine, and morphine-3-glucuronide (M3G) were measured after intraperitoneal injection of 5 mg/kg M6G in another 14 P-gp knockout and 14 wildtype mice. No difference neither in the dose response relationship, nor in the time course of response latency times were observed between P-gp knockout and wildtype mice. However, latency times increased with higher doses of M6G, with antinociception significantly different from placebo at a M6G dose of 5 and 10 mg/kg. P-gp knockout mice tended to have higher plasma concentrations than the wildtype. However, plasma concentrations widely overlapped between groups and therefore no statistical significant group difference could be detected. We conclude that despite reported doubling of M6G brain uptake, absence of mdr1a coded P-gp does not enhance antinociceptive effects of M6G in the hotplate test after acute single-dose administration in mdr1a(-/-) knockout mice.

Topics: Analgesics, Opioid; Animals; ATP Binding Cassette Transporter, Subfamily B; ATP-Binding Cassette Transporters; Dose-Response Relationship, Drug; Female; Homozygote; Male; Mice; Mice, Knockout; Morphine; Morphine Derivatives; Pain; Pain Measurement; Random Allocation; Reaction Time

To provide more accurate measurement of morphine and its metabolites for a study of the genetic differences on morphine response, a method for the analysis of morphine and its metabolites is described which has the advantages of increased sensitivity and specificity by using a cleaner extraction. The new extraction method involves both the hydrophobic isolation on a carbon cartridge and ion-exchange isolation on ion-exchange resin which has not preliminary been described for morphine analysis. The combination of these two steps successfully purified drugs from human plasma with maximum removal of interfering substance comparing with a conventional C18 cartridge alone. The analytes are quantified by high-performance liquid chromatography on a reversed-phase C18 column employing a mobile phase consisting of 25% acetonitrile in 0.05 M phosphate buffer (pH 2.1), and 2.5 mM sodium dodecyl sulfate as the pairing ion with a combination of electrochemical and fluorometric detections. The recoveries for morphine (M), morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G) and hydromorphone after the SPE procedure were 86+/-7.1%, 82+/-6.9%, 79+/-6.0% and 85+/-6.0%, respectively. Limits of detection for this method are 0.1 ng/ml for M, and 0.18 ng/ml for M3G and M6G. Limits of quantitation were approximately 0.25 ng/ml for M, and 0.45 ng/ml for M3G and M6G. The present assay was applied to measure M, M3G and M6G content in human plasma to test the applicability and suitability of this method for clinical and research use.

Topics: Chromatography, High Pressure Liquid; Humans; Morphine; Morphine Derivatives; Reference Standards; Reproducibility of Results; Sensitivity and Specificity

Animal and human studies indicate the existence of important sex-related differences in opioid-mediated behavior. In this study the authors examined the influence of morphine on experimentally induced pain in healthy male and female volunteers.. Young healthy men and women (10 of each sex) received intravenous morphine (bolus 0.1-mg/kg dose followed by an infusion of 0.030 mg. kg-1. h-1 for 1 h). Pain threshold and pain tolerance in response to a gradual increase in transcutaneous electrical stimulation, as well as plasma concentrations of morphine and its major metabolites (morphine-6-glucuronide and morphine-3-glucuronide) were determined at regular intervals up to 7 h after the start of morphine infusion. A population pharmacodynamic model was used to analyze the morphine-induced changes in stimulus intensity. The improvement of the model fits by inclusion of covariates (sex, age, weight, lean body mass) was tested for significance. The model is characterized by baseline current, a rate constant for equilibrium between plasma and effect-site morphine concentrations (ke0), and analgesic potency (AC50, or the morphine concentration causing a 100% increase in stimulus intensity for response).. The inclusion of the covariates age, weight, and lean body mass did not improve the model fits for any of the model parameters. For both pain threshold and tolerance, a significant dependency on sex was observed for the parameters ke0 (pain threshold: 0.0070 +/- 0.0013 (+/- SE) min-1 in men vs. 0.0030 +/- 0. 0005 min-1 in women; pain tolerance: 0.0073 +/- 0.0012 min-1 in men vs. 0.0024 +/- 0.0005 min-1 in women) and AC50 (pain threshold: 71.2 +/- 10.5 nm in men vs. 41.7 +/- 8.4 nm in women; pain tolerance: 76. 5 +/- 7.4 nm in men vs. 32.9 +/- 7.9 nm in women). Baseline currents were similar for both sexes: 21.4 +/- 1.6 mA for pain threshold and 39.1 +/- 2.3 mA for pain tolerance. Concentrations of morphine, morphine-3-glucuronide, and morphine-6-glucuronide did not differ between men and women.. These data show sex differences in morphine analgesia, with greater morphine potency but slower speed of onset and offset in women. The data are in agreement with observations of sex differences in morphine-induced respiratory depression and may explain higher postoperative opioid consumption in men relative to women.

Topics: Adult; Analgesics, Opioid; Female; Humans; Infusions, Intravenous; Injections, Intravenous; Male; Models, Biological; Morphine; Morphine Derivatives; Pain Threshold; Prospective Studies; Sex Factors

Formation of conjugated metabolites from morphine at a very low level in brain was studied in vitro in rats. Incubation of a low concentration of 3H-morphine with brain homogenate followed by two successive high-performance liquid chromatographic analyses showed that endogenous morphine is converted by brain enzymes to its 3- and 6-glucuronides (M-3-G and M-6-G), and codeine glucuronide (Cod-G). However, the formation of morphine-6-sulfate was likely to be low if it was produced at all. All of the cerebral hemisphere, brain stem and cerebellum were capable of producing M-3-G, M-6-G and Cod-G, although there were differences in selectivity. The capacity of the brain for glucuronide formation was far less than that of the liver, but UDP-glucuronosyltransferase in brain was much more selective in forming M-6-G and Cod-G than liver enzymes.

Topics: Animals; Brain; Brain Stem; Cerebellum; Chromatography, High Pressure Liquid; Codeine; Glucuronides; Glucuronosyltransferase; Liver; Male; Microsomes, Liver; Morphine; Morphine Derivatives; Rats; Rats, Sprague-Dawley; Telencephalon

1. The pharmacological properties of the active morphine metabolite, morphine-6 beta-D-glucuronide (M6G), and the parent compound were compared in rat locus coeruleus neurons by electrophysiological recording in brain slices. 2. M6G and morphine activated potassium currents in voltage clamped neurons, which were blocked by the opioid receptor antagonist naloxone. 3. Both M6G and morphine behaved as partial agonists that produced maximal responses smaller than the system maximum, which was measured using [Met(5)]-enkephalin. M6G produced a larger maximal response (78%) than morphine (62%), which we estimated was due to a 2 - 4 fold difference in the relative efficacy of the agonists. 4. 3-O-methoxynaltrexone, which has been reported to behave as a selective antagonist of a M6G preferring receptor, was equally effective at blocking currents produced by M6G and the selective mu-opioid receptor agonist DAMGO. 5. M6G currents were occluded by a prior application of morphine, and were reduced when mu-opioid receptors were desensitized by using [Met(5)]-enkephalin. 6. Morphine-3 beta-D-glucuronide did not affect action potential firing or membrane currents in locus coeruleus neurons and had no effect on currents produced by M6G. 7. These results show that the relative efficacy of M6G is higher than morphine in locus coeruleus neurons, contrary to what has been shown using mu-opioid receptors expressed in cell clones.

Topics: Animals; Dose-Response Relationship, Drug; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Locus Coeruleus; Male; Membrane Potentials; Morphine; Morphine Derivatives; Naltrexone; Neurons; Patch-Clamp Techniques; Rats; Rats, Sprague-Dawley; Receptors, Opioid, mu

Twenty-three patients treated with intracerebroventricular (ICV) morphine in this study not only obtained excellent pain relief without rapid increases in dose, but also experienced a reduction in morphine-related side effects. By 24 h after initiation of ICV morphine, the mean trough cerebrospinal fluid (CSF) morphine concentration (approximately 20 microM) was 50-fold higher than the baseline concentration (approximately 0.4 microM), and the CSF concentration of morphine-6-glucuronide (M6G) was undetectable (<0.01 microM). The mean CSF concentration of morphine-3-glucuronide (M3G) decreased 90%, from a baseline concentration of 1 microM to 0.1 microM by Day 7 postventriculostomy. Thereafter, the mean trough CSF M3G concentration remained relatively constant while ICV morphine was continued, although the concomitant M3G plasma concentrations were undetectable (<0.01 microM). The large increase in the CSF morphine concentration in patients receiving ICV morphine strongly suggests that increased CSF morphine levels are unlikely to be the primary cause of analgesic tolerance or undesirable excitatory side effects (hyperalgesia, myoclonus, seizures) experienced by some patients receiving chronic large-dose systemic morphine.. After initiation of intracerebroventricular morphine, cancer patients experienced excellent pain relief. Although the mean morphine concentration in cerebrospinal fluid increased 50-fold relative to preventriculostomy levels, rapid dose increases did not occur, which suggests that increased cerebrospinal fluid morphine levels are unlikely to be the main cause of analgesic tolerance.

Topics: Administration, Oral; Adult; Aged; Analgesics, Opioid; Female; Humans; Individuality; Injections, Intravenous; Injections, Subcutaneous; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain

The development of an immunoaffinity-based extraction method for the determination of morphine and its glucuronides in human blood is described. For the preparation of an immunoadsorber, specific antisera (polyclonal, host: rabbit) against morphine, morphine-3-glucuronide and morphine-6-glucuronide were coupled to 1,1'-carbonyldiimidazole-activated tris-acrylgel and used for immunoaffinity extraction of morphine and its glucuronides from coronary blood. The resulting extracts were analysed by HPLC with native fluorescence detection. The mean recoveries from spiked blood samples were 71%, 76% and 88% for morphine, morphine-3-glucuronide and morphine-6-glucuronide, respectively. The limit of detection was 3 ng/g blood and the limit of quantitation was 10 ng/g blood for all three analytes. The results of the analysis of coronary blood samples from 23 fatalities due to heroin are presented.

Topics: Chromatography, Affinity; Chromatography, High Pressure Liquid; Drug Overdose; Heroin; Humans; Morphine; Morphine Derivatives; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Fluorescence

This study was performed to determine whether variations in analgesic responses to intrathecal morphine could be explained by cerebrospinal fluid (CSF) concentrations of morphine metabolites. Twenty-four CSF samples were collected at the beginning, middle and end of treatment periods in seven cancer patients with pain of malignant origin. CSF concentrations of morphine-3,beta-glucuronide (M3G) and morphine-6,beta-glucuronide (M6G) metabolites were measured by gas chromatography/mass spectrometry. Analgesic responses to morphine were estimated concurrent with CSF collection using a visual analog scale representing percentages of pain relief. Effective analgesia was defined as > or = 75% pain relief. CSF concentration of M3G and M6G in the 24 samples were 722 +/- 116 ng/ml and 699 +/- 158 ng/ml, respectively. CSF samples were categorized into two groups: (1) those collected during effective analgesia (N=14), and (2) those collected during ineffective analgesia (N=10). M6G levels detected in group 1 samples (effective analgesia) were significantly greater than those found in group 2 samples (ineffective analgesia) (978 +/- 243 ng/ml vs 309 +/- 68 ng/ml, P<0.05). Intergroup differences in CSF M3G concentrations and M3G/M6G ratios were not significant. It is concluded that CSF M6G may be indicative of effectiveness of analgesia in cancer patients subjected to intrathecal morphine.

Topics: Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Female; Humans; Injections, Spinal; Male; Middle Aged; Morphine; Morphine Derivatives

A robust liquid chromatographic mass spectrometric method capable of quantifying morphine, morphine 3-beta-D-glucuronide and morphine 6-beta-D-glucuronide down to 1.0 ng/ml, 5.0 ng/ml and 2.0 ng/ml respectively in human serum is presented. The method was validated over linear ranges of 1.0 to 20.0 ng/ml for morphine, 5.0 to 500.0 ng/ml for morphine 3-beta-D-glucuronide and 2.0 to 100.0 ng/ml for morphine 6-beta-D-glucuronide using deuterated morphine as internal standard. In tandem mass spectrometry conditions, the product ions of morphine-3-glucuronide and morphine-6-glucuronide were the ion m/z corresponding to the morphine moiety. By contrast morphine which presented numerous product ions after collision did not allowed a tandem methodology. Compounds were extracted on 100 mg C18 columns and analysed on the PE Sciex API 300 system equipped with a C18 column and electrospray ionisation interface. The interrun precision of quality controls (1.0, 2.0, 10.0, 20.0 ng/ml for morphine, 5.0, 10.0, 250.0, 500.0 ng/ml for morphine 3-beta-D-glucuronide and 2.0, 4.0, 50.0, 100.0 ng/ml for morphine 6-beta-D-glucuronide) was < or =9.3% and accuracy was between 97.9 and 109.8% for each analyte. Sample stabilities in biological matrix were also investigated. This method has been applied to pharmacokinetic analysis of morphine, morphine 3-beta-D-glucuronide and morphine 6-beta-D-glucuronide in human serum.

Topics: Calibration; Chromatography, High Pressure Liquid; Humans; Mass Spectrometry; Morphine; Morphine Derivatives; Reference Standards; Reproducibility of Results; Sensitivity and Specificity

Cell accumulation, transendothelial permeability, and efflux studies were conducted in bovine brain capillary endothelial cells (BBCECs) to assess the role of P-glycoprotein (P-gp) in the blood-brain barrier (BBB) transport of morphine in the presence and absence of P-gp inhibitors. Cellular accumulation of morphine and rhodamine 123 was enhanced by the addition of the P-gp inhibitors N-{4-[2-(1,2,3,4-tetrahydro-6,7dimethoxy-2-isoquinolinyl)-ethyl]-phenyl}-9,10-dihydro-5-methoxy-9- carboxamide (GF120918), verapamil, and cyclosporin A. Positive (rhodamine 123) and negative (sucrose and propranolol) controls for P-gp transport also were assessed. Morphine glucuronidation was not detected, and no alterations in the accumulation of propranolol or sucrose were observed. Transendothelial permeability studies of morphine and rhodamine 123 demonstrated vectorial transport. The basolateral to apical (B:A) fluxes of morphine (50 microM) and rhodamine (1 microM) were approximately 50 and 100% higher than the fluxes from the apical to the basolateral direction (A:B), respectively. Decreasing the extracellular concentration of morphine to 0.1 microM resulted in a 120% difference between the B:A and A:B permeabilities. The addition of GF120918 abolished any significant directionality in transport rates across the endothelial cells. Efflux studies showed that the loss of morphine from BBCECs was temperature- and energy-dependent and was reduced in the presence of P-gp inhibitors. These observations indicate that morphine is transported by P-gp out of the brain capillary endothelium and that the BBB permeability of morphine may be altered in the presence of P-gp inhibitors.

Topics: Analgesics, Opioid; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Blood-Brain Barrier; Brain; Capillaries; Cattle; Cells, Cultured; Diffusion; Endothelium, Vascular; Morphine; Morphine Derivatives

The study of chronic in utero exposure to heroin and morphine in the human is limited by polysubstance abuse. The guinea pig was used as a model for the human to determine the in vivo and in vitro effect of chronic morphine exposure on morphine metabolism in the pregnant dam and her offspring. In vivo pharmacokinetics of morphine were examined in pregnant guinea pigs following pretreatment with either saline or morphine. In vitro hepatic enzyme kinetics were also examined in a similar group of pregnant dams and their fetuses. Additional pregnant dams were allowed to give birth and their pups' enzyme kinetics were studied at 1, 3, and 7 days. Apparent V(MAX) for the formation of both morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) formation was significantly increased in the morphine-treated pregnant guinea pig. However, no effect of morphine treatment was detectable on the in vivo pharmacokinetics of morphine in the pregnant dam. The apparent morphine K(M) for the formation of M3G was significantly different than the apparent K(M) for the formation of M6G. Significant age effects on the enzyme kinetics were found. The apparent V(MAX) for the formation of both glucuronides increased through the neonatal period. Through literature comparisons, the guinea pig was shown to have in vivo pharmacokinetics similar to the pregnant human, and the guinea pig pups were found to have enzyme development consistent with in vivo pharmacokinetic development seen in human neonates, infants and children.

Topics: Animals; Female; Guinea Pigs; Kinetics; Maternal-Fetal Exchange; Morphine; Morphine Derivatives; Pregnancy

Morphine (MOR) is an opioid analgesic used for the treatment of moderate to severe pain. MOR is extensively metabolized to morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G). A rapid and sensitive method that was able to reliably detect at least 0.5 ng/ml of MOR and 1.0 ng/ml of M6G was required to define their pharmacokinetic profiles. An LC-MS-MS method was developed in our laboratory to quantify all three analytes with the required sensitivity and a rapid turnaround time. A solid-phase extraction (SPE) was used to isolate MOR, M3G, M6G, and their corresponding deuterated internal standards from heparinized plasma. The extract was injected on a LC tandem mass spectrometer with a turbo ion-spray interface. Baseline chromatographic separation among MOR, M3G, and M6G peaks was achieved on a silica column with an aqueous organic mobile phase consisting of formic acid, water, and acetonitrile. The total chromatographic run time was 3 min per injection, with retention times of 1.5, 1.9 and 2.4 min for MOR, M6G, and M3G, respectively. Chromatographic separation of M3G and M6G from MOR was paramount in establishing the LC-MS-MS method selectivity because of fragmentation of M3G and M6G to MOR at the LC-MS interface. The standard curve range in plasma was 0.5-50 ng/ml for MOR, 1.0-100 ng/ml for M6G, and 10-1000 ng/ml for M3G. The inter-day precision and accuracy of the quality control (QC) samples were <7% relative standard deviation (RSD) and <6% relative error (R.E.) for MOR, <9% RSD and <5% R.E. for M6G, and <3% RSD and <6% R.E. for M3G. Analyte stability during sample processing and storage were established. Method ruggedness was demonstrated by the reproducible performance from multiple analysts using several LC-MS-MS systems to analyze over one thousand samples from clinical trials.

Topics: Chromatography, Liquid; Humans; Mass Spectrometry; Morphine; Morphine Derivatives; Organic Chemicals; Reproducibility of Results; Silicon Dioxide; Solvents

A high-performance liquid chromatography tandem mass spectrometry-mass spectrometry (LC-MS-MS) assay was developed for the analyses of morphine, morphine glucuronides and normorphine in plasma samples from rats. The analytes were extracted by using C2 solid-phase extraction cartridges. The extraction recoveries were 100% for morphine, 84% for morphine-3-glucuronide, 64% for morphine-6-glucuronide and 88% for normorphine. Both intra- and inter-assay variabilities were below 11%. Using a plasma sample size of 100 microliters, the limits of detection were 13 nmol l-1 (3.8 ng ml-1) for morphine, 12 nmol l-1 (5.5 ng ml-1) for morphine-3-glucuronide, 26 nmol l-1 (12 ng ml-1) for morphine-6-glucuronide and 18 nmol l-1 (5.0 ng ml-1) for normorphine, at a signal-to-noise ratio of 3. The present assay was applied to a pharmacokinetic study in rats after intraperitoneal administration of morphine.

Topics: Analgesics, Opioid; Animals; Area Under Curve; Biotransformation; Calibration; Chromatography, High Pressure Liquid; Half-Life; Male; Mass Spectrometry; Morphine; Morphine Derivatives; Rats; Rats, Sprague-Dawley; Solutions

This communication describes an improved one-step solid-phase extraction method for the recovery of morphine (M), morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) from human plasma with reduced coextraction of endogenous plasma constituents, compared to that of the authors' previously reported method. The magnitude of the peak caused by endogenous plasma components in the chromatogram that eluted immediately before the retention time of M3G has been reduced (approximately 80%) significantly (p < 0.01) while achieving high extraction efficiencies for the compounds of interest, viz morphine, M6G, and M3G (93.8 +/- 2.5, 91.7 +/- 1.7, and 93.1 +/- 2.2%, respectively). Furthermore, when the improved solid-phase extraction method was used, the extraction cartridge-derived late-eluting peak (retention time 90 to 100 minutes) reported in our previous method, was no longer present in the plasma extracts. Therefore the combined effect of reducing the recovery of the endogenous components of plasma that chromatographed just before the retention time of M3G and the removal of the late-eluting, extraction cartridge-derived peak has resulted in a decrease in the chromatographic run-time to 20 minutes, thereby increasing the sample throughput by up to 100%.

Topics: Analgesics, Opioid; Chromatography, High Pressure Liquid; Drug Monitoring; Humans; Morphine; Morphine Derivatives; Reproducibility of Results

A 46-year-old woman suffering from a reactive depression was admitted to the emergency room in coma and with severe respiratory failure. She later developed cardiovascular instability and general convulsions. Two days following admission the patient had no respiratory effort but was able to communicate in writing that she had ingested a large amount of controlled-release morphine tablets. Following treatment with naloxone she was successfully weaned from the respirator the next day.. Sampling for determination of plasma and urine concentrations of morphine and its metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) was started 60 h after the presumed time of intake and continued up to 8 days after admission.. The initial plasma concentrations of morphine, M3G and M6G were 2160, 13100 and 2330 nM, respectively, compatible with a lethal dose in an opioid-naive patient. The urinary recovery of morphine, M3G and M6G corresponded to 6.8 mmol, equivalent to an oral intake of at least 2500 mg.. The plasma concentrations of morphine and morphine metabolites documented in this case, indicative of considerable absorption of drug, demonstrate that prolonged observation is necessary following intoxications with controlled-release morphine tablets. This case also highlights the importance of continuous follow-up of oral morphine therapy, so that unused drug is not left unaccounted for in the patient's home.

Topics: Absorption; Analgesics, Opioid; Coma; Delayed-Action Preparations; Depression; Female; Follow-Up Studies; Humans; Middle Aged; Morphine; Morphine Derivatives; Respiratory Insufficiency; Seizures; Suicide, Attempted; Tablets

The influence of ranitidine on morphine metabolism, with special emphasise on the ratio between morphine-3-glucuronide and morphine-6-glucuronide was studied in isolated guinea pig hepatocytes. Ranitidine reduced the Kel of morphine dose-dependently with a maximum effect of 50%, and increased the relative concentration of morphine-6-glucuronide to morphine-3-glucuronide. These effects could be due to a direct or indirect effect on the conjugation enzymes involved, or an effect on the transport of morphine or glucuronides across cell membranes. The latter explanation was rejected on the basis of the observation that the ratios between intra- and extracellular concentrations of morphine, morphine-3-glucuronide and morphine-6-glucuronide were not influenced by ranitidine. Increasing concentrations of ranitidine gradually decreased the morphine-3-glucuronide/morphine-6-glucuronide ratio by up to 21%. This could stem from interference of energy or co-substrate supply, or through direct effects on the different UDPGTases involved. The observation that the present effect on morphine glucuronidation was the opposite of that observed when administering a known co-substrate (UDPGA) depletor, indicated that in all probability the effect of ranitidine was a direct inhibition on the uridine 5'-diphosphate glucuronyltransferases involved, with a more pronounced effect for the isoenzymes responsible for the 3'-glucuronidation.

Topics: Animals; Glucuronosyltransferase; Guinea Pigs; Histamine H2 Antagonists; Liver; Male; Morphine; Morphine Derivatives; Ranitidine

Recently, clinical reports have suggested a relationship between the occurrence of hyperalgesia, allodynia and/or myoclonus and treatment with high doses of morphine in humans. Although few clinical descriptions of these phenomena are available, experimental work supports the notion that high doses of morphine may play a pathogenetic role in the observed behavioural syndrome.. Six patients, four with malignant and two with chronic, non-malignant pain conditions, treated with moderate to high doses of oral, continuous intravenous infusion or intrathecal morphine developed hyperalgesia, allodynia and/or myoclonus. When the side-effects occurred, blood or CSF samples were taken and analyzed for contents of morphine, morphine-6-glucuronide (M-6-G) and morphine-3-glucuronide (M-3-G).. When comparing the plasma and CSF concentrations from these patients with data from available literature obtained from patients not suffering from these side-effects, it was demonstrated that the values deviated in five patients. In all six patients, the side-effects disappeared after substituting morphine with other opioid agonists or after lowering the daily dose of morphine.. These results may indicate that elevated concentrations of M-3-G in plasma as well as the plasma and CSF M-3-G/M-6-G ratios may play a pathogenetic role in the development of hyperalgesia, allodynia and myoclonus.

Topics: Aged; Analgesics, Opioid; Female; Glucuronosyltransferase; Humans; Hyperalgesia; Male; Middle Aged; Morphine; Morphine Derivatives; Myoclonus

The development of specific antisera for immunochemical determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide is described. Morphine was N-demethylated to normorphine and N-alkylated to give N-aminopropyl-normorphine as hapten for antisera against morphine. As haptens for antisera against morphine-3-glucuronide and morphine-6-glucuronide, N-aminopropyl-nor-morphine was glucuronidated in position 3 or 6 respectively. Each of these three haptens were coupled to BSA employing the glutaraldehyde method to obtain three different immunogens. Immunisation of rabbits with these conjugates gave anti-morphine, anti-morphine-3-glucuronide and anti-morphine-6-glucuronide antisera, which were tested in a competitive, heterogeneous radioimmunoassay. Tracers for this radioimmunoassay procedure were synthesised by substitution of morphine and morphine-6-glucuronide in position 2 with 125I and indirect iodination of the morphine-3-glucuronide hapten according to the method of Bolton and Hunter. The resulting antisera show very specific reactions with morphine, morphine-3-glucuronide and morphine-6-glucuronide. Cross reactivities of each antiserum with structurally related opiates and opioides are very low. The cross reactivities of the anti-morphine antiserum against morphine-3-glucuronide, morphine-6-glucuronide, codeine, codeine-6-glucuronide or dihydrocodeine were less than 0.3%, the anti-morphine-3-glucuronide antiserum against morphine, morphine-6-glucuronide, codeine, codeine-6-glucuronide or dihydrocodeine less than 0.1% and the anti-morphine-6-glucuronide antiserum against morphine, morphine-3-glucuronide, codeine or dihydrocodeine less than 0.1%, against codeine-6-glucuronide less than 2.3%. The determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide in blood samples (limit of detection= 3, 1, 0.5 ng/g) of nine cases of fatal heroin overdose with this radioimmunoassay method and the comparison with a GC/MS method is described.

Topics: Animals; Cross Reactions; Gas Chromatography-Mass Spectrometry; Humans; Morphine; Morphine Derivatives; Rabbits; Radioimmunoassay; Sensitivity and Specificity

A venous blood sample taken at autopsy cannot be considered to represent the antemortem blood concentration of a particular substance. Autolytic processes cause disintegration and increasing permeability of the physiological and anatomical barriers such as vascular walls and lead to changes in substance concentrations. In the present study, the experimental design represents an in vitro postmortem simulation of a drug substance crossing a venous wall. The postmortem behavior of morphine, morphine-3- and morphine-6-glucuronide was investigated. A Chien-Valia-diffusion chamber with a patch of inferior vena cava as diffusion barrier was used. For optimal simulation of postmortem events, vein sampling was restricted to selected autopsy cases. Parameters for the analysis of diffusion across the vascular tissue were dependence on time, temperature, and initial substance concentrations. The penetration behavior simulating venous efflux and influx of the substances was studied by different orientation of the venous wall in the experiments. Rhodamine B was used as a model substance to visualize the binding to the tissue and the passage across the venous wall. The permeation of morphine, morphine-3- and morphine-6-glucuronide across a vein tissue was found to be mainly dependent on the disintegration of the vascular wall and on the postmortem time period as well as on concentration gradients. From the data of this preliminary in vitro study, it can be concluded that a lag time for transvascular diffusion exists postmortem. However, it could be demonstrated, that adsorption to and penetration into the vascular tissue may alter intraluminal blood concentrations even at an early stage of the postmortem time period.

Topics: Biological Transport; Diffusion Chambers, Culture; Dose-Response Relationship, Drug; Endothelium, Vascular; Fluorescent Dyes; Humans; Morphine; Morphine Derivatives; Postmortem Changes; Rhodamines; Vena Cava, Inferior

Topics: Adult; Drug Overdose; Heroin; Humans; Male; Morphine; Morphine Derivatives; Postmortem Changes; Tissue Distribution

A rapid and selective reversed-phase high-performance liquid chromatographic assay with gradient elution and diode-array detection for diacetylmorphine, morphine, codeine, and their free and glucuronidated metabolites in plasma, was developed. After addition of ethylmorphine as internal standard the plasma samples were extracted using C18 ODS-2 solid-phase columns with a recovery better than 80%. The limit of quantitation using an injection volume of 2 microl was 25 ng/ml for each compound. The intra- and inter-day precision was better than 5%. The described method cannot only be used for pharmacokinetic studies but also for intoxication cases to monitor a wide range of opiates.

Topics: Chromatography, High Pressure Liquid; Heroin; Humans; Injections, Intravenous; Morphine; Morphine Derivatives; Narcotics; Spectrophotometry, Ultraviolet

Concentrations of morphine and its 3- and 6-glucuronide metabolites (M3G and M6G) in plasma, brain, and urine of rats exposed to morphine for either 24 or 48 h were measured using high-performance liquid chromatography. In another group of morphine-treated rats, the intensity of naloxone-precipitated withdrawal behaviours was monitored at 24 and 48 h. The behavioural effects of M3G in opiate-naive and opiate-dependent rats were also investigated. Morphine was present in plasma, urine, and brain at 24 and 48 h, whereas M3G was detected in plasma and urine only. M6G was not present in detectable quantities in either plasma, urine, or brain. Although plasma concentrations of M3G were similar in both time groups, rats treated for 48 h had significantly larger quantities of M3G in their urine than did the other treatment groups. The incidence of withdrawal behaviour was significantly higher in animals exposed to morphine for 48 h than in those with only 24 h of exposure, M3G had no behavioural effects in the opiate-naive rats and did not precipitate an opiate-abstinence syndrome in morphine-dependent rats. From these results, it was concluded that although M3G is the major product formed by morphine breakdown in rats, it is unlikely that it is involved in the development of morphine dependence in this species.

Topics: Animals; Body Weight; Brain; Defecation; Female; Morphine; Morphine Dependence; Morphine Derivatives; Naloxone; Narcotic Antagonists; Rats; Rats, Wistar; Substance Withdrawal Syndrome

The influence of experimentally induced renal failure on the disposition of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) was examined in seven sheep infused intravenously with morphine for 6 hr. Between 5 and 6 hr, blood was collected from the aorta, pulmonary artery, hepatic, hepatic portal and renal veins and posterior vena cava. Additional samples from the aorta and urine were collected up to 144 hr. Morphine, M3G and M6G were determined in plasma and urine by high-performance liquid chromatography. Constant concentrations of morphine, but not of M3G and M6G, were achieved in plasma between 5 and 6 hr. Significant (P < .001) extraction of morphine by the liver (0.72 +/- 0.05) and kidney (0.42 +/- 0.15) occurred. Compared with sheep with normal kidneys (Milne et al., 1995), renal failure did not alter (P = .11) the mean total clearance of morphine (1.5 +/- 0.3 liters/min); clearance by the kidney was less (P < .001). However, a paired comparison using sheep common to this study and from the study when their kidneys were normal revealed a significant reduction in mean total clearance of 25%. The renal extraction of M3G and M6G and urinary recovery of the dose as summed morphine, M3G and M6G were reduced by renal failure. The kidney metabolized morphine to M3G. The data suggest that nonrenal elimination of M3G becomes more important during renal failure.

Topics: Animals; Area Under Curve; Chromatography, High Pressure Liquid; Infusions, Intravenous; Liver; Morphine; Morphine Derivatives; Renal Insufficiency; Sheep

For the interpretation of the concentration of morphine in blood samples of heroin consumers information about the concentration of the analgesic active morphine metabolite morphine-6-glucuronide is very important. Thus a simple but specific clean-up procedure based on immuno-affinity chromatography is presented for the extraction of morphine, morphine-3-glucuronide and morphine-6-glucuronide from whole blood in cases of fatal heroin overdose. The preparation of the immunoabsorber by immobilization of antibodies against morphine-3-BSA and morphine-6-KLH with carbonyldiimidazole-activated trisacrylgel is described. The separation of the extracts is achieved by HPLC using native fluorescence detection. The limits of detection for this method are 10ng for morphine and morphine glucuronides/g blood. The results for the concentration of morphine and morphine glucuronides in blood from seven cases of heroin overdose are presented. By calculating the quotients for the concentrations of morphine-6-glucuronide/morphine the time elapsed since the last intake of heroin is estimated.

Topics: Antibodies; Chromatography, Affinity; Chromatography, High Pressure Liquid; Drug Overdose; Heroin; Heroin Dependence; Humans; Immunosorbents; Morphine Derivatives; Postmortem Changes; Time Factors

Humans and guinea pigs metabolise morphine extensively, forming the isomers morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in relatively similar ratios. Both metabolites are formed in the liver, and their greater polarity relative to the parent aglycone may limit their permeability across hepatic membranes. This study compared the disposition of hepatically-generated M3G and M6G in perfused livers isolated from guinea pigs.. Livers were perfused at 30 ml/min in a non-recirculating manner with Krebs bicarbonate buffer containing morphine (6 to 7 microM). Perfusing medium, venous perfusate and bile were collected at regular intervals and concentrations of morphine, M3G and M6G determined by reversed-phase HPLC.. Concentrations of morphine, M3G and M6G in perfusate and the rates of biliary excretion of M3G and M6G were consistent between 20 and 50 min of perfusion. The mean (+/-s.d.) ratio for the rate of formation of M3G relative to M6G was 3.7 +/- 1.5. A mean 33 +/- 3% of morphine extracted by the liver was recovered as summed M3G and M6G. Of the M3G and M6G formed during a single passage, 19 +/- 11% and 9 +/- 9%, respectively, was excreted into bile; the values were significantly different (P = 0.002).. A greater fraction of hepatically-generated M3G excreted into bile compared to that for M6G reflects differences in their relative transport across sinusoidal and canalicular membranes of hepatocytes, possibly via carrier-mediated systems.

Topics: Analgesics, Opioid; Animals; Bile; Guinea Pigs; In Vitro Techniques; Liver; Male; Morphine; Morphine Derivatives; Perfusion

Morphine, morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G), and 6-monoacetylmorphine (6-MAM) were isolated from body fluids using solid-phase extraction and determined by means of atmospheric pressure chemical ionization-mass spectrometry-liquid chromatography (APCI-LC-MS) in selected ion monitoring mode. The following ions were monitored: m/z 286 for morphine; m/z 286 and 462 for M3G and M6G; m/z 211, 268, and 328 for 6-MAM; and m/z 289 for morphine-d3 (internal standard). The recoveries ranged from 82 to 89% The limits of detection were as follows: 0.1 ng/mL (morphine), 0.5 ng/mL (6-MAM), and 1 ng/mL (M3G and M6G). The analytes were determined in samples taken from 21 heroin-overdose victims. Twenty-one blood samples, 11 cerebrospinal fluid (CSF) samples, 12 vitreous humor (VH) samples, and 6 urine samples were investigated. Blood concentrations (ng/mL) of morphine ranged from 8 to 1539, of M3G from 111 to 941, of M6G from 32 to 332, and of 6-MAM from 0 to 73. The levels of morphine were correlated with glucuronide values and with 6-MAM. The concentrations of morphine, M3G, and M6G in CSF were, as a rule, lower than in blood and lower in VH than in CSF. The concentrations of morphine and molar ratios of M6G-morphine in blood and CSF were correlated. Low ratios of M3G-morphine and M6G-morphine in blood of heroin-overdose victims indicated short survival time after drug intake.

Topics: Adolescent; Adult; Atmospheric Pressure; Autopsy; Chromatography, Liquid; Female; Heroin; Heroin Dependence; Humans; Male; Mass Spectrometry; Morphine; Morphine Derivatives; Narcotics; Urine; Vitreous Body

A selective assay of morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G), morphine, codeine, codeine-6-glucuronide (C6G) and 6-monoacetylmorphine (6-MAM) based on liquid chromatography atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) is described. The drugs were extracted from serum, autopsy blood, urine, cerebrospinal fluid or vitreous humor using C18 solid-phase extraction cartridges and subjected to LC-APCI-MS analysis. The separation was performed on an ODS column in acetonitrile-50 mM ammonium formate buffer, pH 3.0 (5:95), using a flow-rate gradient from 0.6 to 1.1 ml/min (total analysis time was 17 min). The quantitative analysis was done using deuterated analogues of each compound. Selected-ion monitoring detection was applied: m/z 286 (for morphine, M3G-aglycone and M6G-aglycone), 289 (for morphine-d3, M3G-d3-aglycone and M6G-d3-aglycone), 300 (for codeine and C6G-aglycone), 303 (for C6G-d3-aglycone), 306 (for codeine-d6), 328 (for 6-MAM), 334 (for 6-MAM-d6), 462 (for M3G and M6G), 465 (for M3G-d3 and M6G-d3), 476 (for C6G) and 479 (for C6G-d3). The limits of quantitation were: 1 microg/l for morphine, 2 microg/l for 6-MAM, 5 microg/l for M3G, M6G and codeine and 200 microg/I for C6G. The recovery ranged from 85 to 98% for each analyte. The method appeared very selective and may be used for the routine determination of opiates in body fluids of heroin abusers and patients treated with opiates.

Topics: Analgesics, Opioid; Body Fluids; Chromatography, Liquid; Codeine; Humans; Mass Spectrometry; Morphine; Morphine Derivatives; Reproducibility of Results; Sensitivity and Specificity

Topics: Biological Transport; Chemical Phenomena; Chemistry, Physical; Chloroform; Hydrogen-Ion Concentration; Morphine Derivatives; Narcotics; Octanols; Potentiometry; Solutions; Solvents

A 32-year-old man with chronic intractable right lower extremity pain unresponsive to multiple neurosurgical and pharmacologic treatments, including intrathecal morphine administration, was successfully treated with sciatic nerve block, discontinuance of opioid therapy, and psychologic interventions. Plasma and urine ratios of morphine metabolites morphine-3-glucuronide and morphine-6-glucuronide were analyzed at the beginning of our interventions, and the results indicated that morphine-3-glucuronide levels were significantly higher than morphine-6-glucuronide levels. The possible association between the observed morphine metabolite ratio and the intractable pain in patients resistant to opioids may have potential clinical implications.

Topics: Adult; Analgesics, Opioid; Drug Resistance; Humans; Injections, Spinal; Male; Morphine; Morphine Derivatives; Nerve Block; Pain, Intractable; Treatment Failure

A novel, highly sensitive and specific bioanalytical method has been developed for the simultaneous determination of morphine and its major metabolites, morphine-3-glucuronide and morphine-6-glucuronide, in human plasma, using noroxymorphone as the internal standard. The analytes are isolated from human plasma using a nonpolar/polar C2 solid-phase extraction cartridge and analyzed by high-performance liquid chromatography with serial detection using electrochemical detection for morphine, morphine-6-glucuronide (M6G), and noroxymorphone and fluorescence detection for morphine-3-glucuronide (M3G). The limit of quantitation (sensitivity) using a 0.5-ml sample of plasma is 1 ng/ml, 10 ng/ml, and 5 ng/ml for morphine, M3G, and M6G, respectively. Standard curves were linear (correlation coefficients > 0.999) over the ranges 1-30 ng/ml, 10-500 ng/ml, and 5-100 ng/ml for morphine, M3G, and M6G, respectively. The overall interday accuracy of the method was -1.58% for morphine, 2.27% for M3G, and -5.34% for M6G. The assay is routinely used for the study of morphine, M3G, and M6G pharmacokinetics after oral administration of morphine.

Topics: Chromatography, High Pressure Liquid; Drug Stability; Morphine; Morphine Derivatives; Narcotics

Eight patients undergoing major maxillary surgery were given sustained-release morphine (100 mg MST Continus) rectally, immediately after induction of general anaesthesia. Blood samples for assay were taken just prior to morphine administration, together with a further 11 samples over the following 24 h. Assay of the plasma for morphine, morphine-3-glucuronide and morphine-6-glucuronide was carried out using a validated high-performance liquid chromatography technique. Morphine Tmax ranged from 3 h to 12 h (median 6 h), Cmax 8.0-40.0 ng/ml and AUC0-24 90.1-429.7 ng/h/ml in subjects offering blood samples over the 24-h period. Likewise, morphine-3-glucuronide Tmax ranged from 3 h to 24 h (median 9 h), Cmax 153-370 ng/ml and AUC0-24 2776-4390 ng/h/ml. Morphine-6-glucuronide Tmax ranged from 8 h to 12 h (median 10 h), Cmax 24-59 ng/ml and AUC0-24 137-803 ng/h/ml. Morphine and morphine metabolite AUC0-24 ratios were calculated, but they did not correlate with analgesic needs. The AUC0-24 ratios were similar to those following oral and rectal dosing in other studies involving cancer patients. The wide variation of individual morphine and metabolite plasma levels, and their AUC ratios indicates considerable interpatient variability in the absorption and metabolism of rectal sustained-release morphine. This large interpatient variation may indicate that it is not suitable for acute pain, because analgesic requirements change much more rapidly than in the chronic pain situation where individual patient titration can take place.

Topics: Administration, Rectal; Adolescent; Adult; Analgesics, Opioid; Area Under Curve; Female; Humans; Male; Morphine; Morphine Derivatives

Morphine, morphine-6-glucuronide (M6G) tolerance and cross-tolerance between morphine and M6G have been evaluated in mice. Daily administration of equipotent doses of M6G and morphine induced similar declines in antinociception over 9 days of treatment. However, a higher dose of M6G than morphine is required in tolerant animals to recover the initial response. In studies where daily morphine doses were substituted by M6G administration, on specific days, there was a significant fall in M6G antinociception on those days immediately following morphine administration, relative to the response to continued morphine (a decrease of 53.7% on day 2, P < 0.001 and a decrease of 62.5% on day 11, P < 0.05) and M6G (a decrease of 45.4% on day 2, P < 0.05) exposure. The decrease was independent of treatment duration and dosage. This decrease in the antinociceptive effect of M6G after morphine was avoided after clofibrate treatment, an inhibitor of (-)morphine metabolism. Determination of morphine and its metabolites in plasma revealed that morphine-3-glucuronide (M3G) concentration was significantly lower (P < 0.001) in animals treated with clofibrate (8.3 +/- 8.3 ng/ml) than in controls (422 +/- 80 ng/ml). The dose-response curve for M6G was shifted to the right by prior administration of M3G. These results suggest that during morphine treatment the antinociceptive effect of M6G may be antagonized by the other metabolite, M3G.

Topics: Analgesics, Opioid; Animals; Chromatography, High Pressure Liquid; Clofibrate; Dose-Response Relationship, Drug; Drug Tolerance; Hypolipidemic Agents; Injections, Subcutaneous; Male; Mice; Morphine; Morphine Derivatives; Pain Measurement

Steady-state pharmacokinetics of morphine and morphine-6-glucuronide (M-6-G) after intravenous administration of either morphine or M-6-G were determined in healthy volunteers. With a dosing regimen calculated on the basis of data obtained in a first series of experiments in four subjects (morphine: intravenous loading dose of 0.24 mg/kg for 5 minutes and an intravenous infusion of 0.069 mg.kg-1.hr-1 for 4 hours; M-6-G: loading dose of 0.011 mg/kg for 5 minutes and an infusion of 0.006 mg.kg-1.hr-1 for 4 hours), it was possible to yield plasma concentrations of morphine and M-6-G in another four subjects close to predefined targeted levels (35 and 45.5 ng/ml morphine and M-6-G, respectively). This dosing regimen may be used in further pharmacodynamic studies to compare the analgesic effects of morphine and M-6-G. In addition, metabolite kinetics of M-6-G were calculated as a function of time with use of a linear systems approach to the estimation of rate and fraction of morphine glucuronidation to M-6-G.

Topics: Adult; Analgesics, Opioid; Chromatography, High Pressure Liquid; Drug Administration Schedule; Humans; Infusions, Intravenous; Linear Models; Male; Morphine; Morphine Derivatives; Reference Values

We investigated the nature of interaction of morphine-3-O-beta-D-glucuronide (M3G) and morphine-6-O-beta-D-glucuronide (M6G) with opioid binding sites at the mu-, delta- and kappa-opioid receptors (mu-OR, delta-OR and kappa-OR) in cerebral membranes. Saturation binding experiments revealed a competitive interaction of M6G with all three opioid receptors. Inhibition binding experiments at the mu-OR employing combinations of morphine and M6G resulted in a rightward shift of the IC50 for morphine proportional to the M6G concentration, thus strengthening the finding of competitive interaction of M6G at the mu-opioid binding site. Data in absence and presence of M6G were included in a three-dimensional model. Compared to a model with one binding site a model with two binding sites significantly improved the fits. This might indicate that different mu-OR subtypes are involved. Hydrolysis of M6G to morphine was investigated and did not occur. Therefore the effects of M6G on binding to the mu-OR were due to M6G and not due to morphine. In contrast, M3G at the three opioid receptors was found to inhibit binding being about 300 times weaker than morphine. This effect was well explained by the amount of contaminating morphine (about 0.3%) identified by HPLC. We conclude that M6G binds to mu-, delta- and kappa-OR in a competitive manner. Some of our results on the mu-OR suggest two binding sites for agonists at the mu-OR and that M6G binds to both sites. Our results suggest that the high potency of M6G as an analgesic is mediated through opioid receptors. In contrast, M3G does not interact with the mu-, delta- or kappa-OR. We therefore doubt that any effect of M3G is mediated via opioid receptors.

Topics: Animals; Binding Sites; Brain; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Enkephalins; Female; Guinea Pigs; Male; Morphine; Morphine Derivatives; Receptors, Opioid, delta; Receptors, Opioid, kappa; Receptors, Opioid, mu

It has previously been shown that guinea pig hepatocytes metabolise morphine in a fashion similar to humans. The metabolism of morphine (5 muM) and the formation of metabolites morphine-3-glucuronide, morphine-6-glucuronide and normorphine was studied in the absence and presence of ethanol (5, 10, 25, 60 and 100 mM) in freshly isolated guinea pig hepatocytes. In order to gain more detailed information, a mathematical model was estimated on experimental data and used to analyse the effects of ethanol on the reaction rates of the different morphine metabolites. Ethanol inhibited the rate of morphine elimination in a dose-related manner, at the high ethanol concentrations the elimination rate was 40 per cent of the control rate. The formation of morphine-glucuronides was influenced in a biphasic manner. Five and 10 mM ethanol increased both the morphine-3-glucuronide and morphine-6-glucuronide levels after 60 min incubation compared to the control, whereas at the higher ethanol concentrations (25-100 mM) the levels of morphine-glucuronides were reduced. Data from the mathematical model, however, demonstrated that the reaction rates for morphine-glucuronide formation were decreased at all ethanol concentrations and in a dose-dependent manner, the interpretation of this being that at the lower (5 and 10 mM) ethanol concentrations employed in this study, other metabolic pathways of morphine are more heavily inhibited than the glucuronidations, resulting in a shunting towards morphine-3-glucuronide and morphine-6-glucuronide. The pharmacodynamic consequences of these pharmacokinetic effects are thus somewhat difficult to predict since morphine-6-glucuronide has a higher agonist potency than morphine. At high concentrations ethanol inhibition of morphine metabolism will increase the concentration of morphine and subsequently the euphoric and the toxic effects. The lower quantities of morphine-6-glucuronide formed in the presence of high ethanol concentrations on the other hand most probably imply reduction of such effects and the net pharmacodynamic effect would be uncertain. At low ethanol concentrations, however, morphine-6-glucuronide concentrations increased and morphine metabolism was less inhibited leading to a possible potentiation of the effects of morphine. Thus, a low ethanol concentration might exert a more pronounced ethanol-drug effect interaction than a higher ethanol concentration.

Topics: Animals; Cell Separation; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Drug Interactions; Ethanol; Guinea Pigs; Liver; Male; Models, Theoretical; Morphine; Morphine Derivatives; Narcotics; Regression Analysis; Solvents

Ribonuclease protection assays were performed on the basal hypothalamus (BH), the preoptic area (POA) and the thalamus (THAL) from female guinea pigs that were ovariectomized and implanted with morphine (n = 8) or placebo (n = 8) pellets for 1 week. An antisense [32P]rUTP labeled riboprobe, representing a 280 bp fragment of the guinea pig mu-opioid receptor gene (spanning putative TM II through eight residues of TM IV), protected a single RNA band of 280 bp. In contrast to the rat, the guinea pig THAL expressed less mu-opioid receptor mRNA than both POA and BH. Morphine treatment caused a significant decrease (15.6 +/- 5.8%) in mu-opioid receptor mRNA expression in the BH, while POA and THAL were not different from placebo controls. Therefore, in conjunction with our previous findings of a downregulation of mu-opioid receptors, mu-opioid receptor mRNA is downregulated in the mediobasal hypothalamus of female guinea pigs following chronic morphine treatment.

Topics: Analgesics, Opioid; Animals; Down-Regulation; Drug Tolerance; Female; Gene Expression; Guinea Pigs; Hypothalamus, Middle; Morphine; Morphine Derivatives; Ovariectomy; Receptors, Opioid, mu; RNA, Messenger

A pharmacokinetic study was undertaken to compare the pharmacokinetics of morphine after an intravenous dose with the pharmacokinetics after a sublingual dose administered from an aerosol. Plasma levels of morphine, morphine-3-glucuronide and morphine-6-glucuronide were measured in five normal volunteers after morphine administration by the intravenous route and from a novel sublingual pressurized aerosol formulation. The mean (+/- s.d.) bioavailability of the sublingual aerosol morphine was 19.7 +/- 6.7%. The morphine-3-glucuronide/morphine and the morphine-6-glucuronide/morphine ratios were 5.1 +/- 1.6 and 1.2 +/- 0.4, respectively, for the intravenous route and 28.3 +/- 11.3 and 5.2 +/- 1.4, respectively, for the sublingual route. The combined total areas under the plots of systemic concentration against time (AUC) for the metabolites after the two routes was not significantly different. When compared with published data for oral administration the results demonstrate that the sublingual aerosol morphine might provide an alternative to conventional methods of morphine delivery, and has similar pharmacokinetics to a sublingual morphine tablet. It has no particular pharmacokinetic advantages over oral morphine, except a potential for a faster onset of analgesia. Bioavailability, maximum plasma concentration, Cpmax, and the time at which the maximum plasma concentration is reached, Tmax, are equivalent to those for orally administered morphine.

Topics: Administration, Sublingual; Adult; Aerosols; Analgesics, Opioid; Female; Humans; Male; Morphine; Morphine Derivatives

A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of morphine and two of its metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), in serum is described. The compounds are extracted from serum using Sep-Pak light C18 solid-phase extraction cartridges, separated on an ODS C18 analytical column (100 x 4.6 mm I.D.) and detected by electrospray ionisation mass spectrometry. The separation was achieved by running a linear gradient from 4 to 70% acetonitrile with formic acid added as modifier. The flow-rate in the column was 1.0 ml/min. After the column, the eluate was subjected to a 1:50 split, with 20 microliters/min delivered to the mass spectrometer and 980 microliters/min delivered to waste. The compounds were detected in the mass spectrometer by selected-ion monitoring for m/z 286.2 for morphine and 462.2 for M3G and M6G. The spray voltage was 2.4 kV and the sampling cone was set at 40 V. The compounds have been quantified in serum over a concentration range of 2.9-60 nmol/l (0.84-17 ng/ml) for morphine, 11-1080 nmol/l (5.0-500 ng/ml) for M3G and 4.3-220 nmol/l (2.0-100 ng/ml) for M6G using external standardisation. Intra-assay and inter-assay precision were in the range of 2.4-9.0% for all compounds. The major advantage with the present LC-MS method was the shorter analysis time, 10 min per sample compared to 45 min per sample with our previous LC method with dual detectors. The LC-MS method has proved to have both the selectivity and sensitivity needed for pharmacokinetic studies.

Topics: Calibration; Chromatography, High Pressure Liquid; Humans; Indicators and Reagents; Mass Spectrometry; Morphine; Morphine Derivatives; Reproducibility of Results

The pharmacokinetics of morphine in plasma and the distribution of morphine and its glucuronidated metabolites within the cerebrospinal fluid were investigated in rabbits. After single morphine dosage, the plasma AUC ratio of morphine-3- glucuronide/morphine was 11.1 compared with 0.14 for morphine-6-glucuronide/morphine. The similar elimination half-lives of morphine (107 min), morphine-3-glucuronide (122 min), and morphine-6-glucuronide (105 min) suggested the glucuronidation to be the rate-limiting step, which was substantiated by the observation that morphine-3-glucuronide becomes eliminated four times faster when applied intravenously. Both after single and repeated morphine administration, the ratios of CSF and plasma levels of the parent drug were higher than those of morphine-3-glucuronide or morphine-6-glucuronide. These data demonstrate a poor penetration of the glucuronides across the blood-brain barrier and do not support the previously postulated accumulation of morphine-6-glucuronide in the central nervous system during chronic morphine treatment.

Topics: Animals; Blood-Brain Barrier; Central Nervous System; Chromatography, High Pressure Liquid; Half-Life; Injections, Subcutaneous; Male; Morphine; Morphine Derivatives; Rabbits

Healthy volunteers were given morphine as an i.v. infusion (10 mg), immediate release (IR) tablets (3 x 10 mg), and as a new controlled release (CR) tablet (30 mg) on separate occasions. Venous blood samples were analyzed for morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) using high-performance liquid chromatography (HPLC). Pupil size, salivation, and central nervous system (CNS) effects were evaluated serially. Pharmacokinetic parameters, calculated using a two-compartment model, were in accordance with previous results for i.v. administration of morphine. The absolute bioavailability of morphine in both IR and in CR tablets was, 32%, and the relative bioavailability of the CR tablet versus the IR tablets was 103% (91-115%, 95% confidence interval). Pupil size and unstimulated saliva production were significantly reduced and CNS effects most pronounced following i.v. infusion of morphine, but were only moderately affected after oral administration with IR or CR tablets. Miosis and reduction of salivation were observed at moderate concentrations of morphine and M6G. A pharmacokinetic/pharmacodynamic model based on previous studies of receptor binding and potency of morphine and its metabolites was used to assess the concentration-effect relationships. According to this model, M6G was four and eight times more potent than morphine in producing miosis and reduction of saliva production, respectively. The same model indicated that intrinsic activities of M6G and morphine were similar for both effect parameters, whereas M3G was either inactive or even opposed the effects of morphine and M6G.

Topics: Administration, Oral; Adult; Biological Availability; Brain; Female; Humans; Injections, Intravenous; Male; Miosis; Morphine; Morphine Derivatives; Salivation

A sensitive method for the analysis of unconjugated morphine, codeine, normorphine and total morphine after hydrolysis of glucuronide conjugates is described. The method was applicable to 50-microliters volumes of plasma. The analytes were converted to heptafluorobutyryl (HFB) derivatives before analysis by gas chromatography-negative ion chemical ionization mass spectrometry. Morphine and codeine were quantified against their [2H3]-isotopomers. Linearity, precision and accuracy were quite acceptable (in the 10(-10)-10(-9) g range), and the absolute limits of detection were < 1 pg.

Topics: Child; Codeine; Gas Chromatography-Mass Spectrometry; Humans; Morphine; Morphine Derivatives; Sensitivity and Specificity; Tritium

Opiate alkaloid-selective, opioid peptide-insensitive mu 3 receptors are present in three murine macrophage cell lines (J774.2; RAW 264.7; BAC1.2F5). The receptor binds morphine, its active metabolite morphine 6-glucuronide and certain other alkaloids, but not morphine 3-glucuronide or any of the opioid peptides tested. The cell lines thus provide valuable model systems for investigation of mu 3-opiate receptors, previously demonstrated to mediate inhibitory effects of morphine on activation of human peripheral blood macrophages (monocytes).

Topics: Animals; Binding, Competitive; Cell Line; Cell Membrane; Kinetics; Macrophages; Mice; Morphine; Morphine Derivatives; Receptors, Opioid, mu

A rapid and selective assay of morphine and its 3- and 6-glucuronides in serum, based on high-performance liquid chromatography-electrospray mass spectrometry has been developed. The analytes and the internal standard, codeine or naltrexone, were subjected to solid-phase extraction, using ethyl solid-phase extraction columns, prior to chromatography. A reversed-phase column and a gradient mobile phase consisting of water and methanol were used. The mass spectrometer was operated in the selected-ion monitoring mode. The following ions were used: m/z 286 for morphine, m/z 300 for codeine, m/z 342 for naltrexone, and m/z 462 for morphine 3- and 6-glucuronides. The limit of quantitation observed with this method was 10 ng/ml morphine, 50 ng/ml morphine-6-glucuronide and 100 ng/ml morphine-3-glucuronide. The present method proved useful for the determination of serum levels of the parent drug and its metabolites in pain patients, heroin addicts and in morphine-treated mice.

Topics: Animals; Calibration; Chromatography, High Pressure Liquid; Heroin Dependence; Humans; Male; Mass Spectrometry; Mice; Mice, Inbred C57BL; Morphine; Morphine Derivatives; Neoplasms; Reference Standards

Opioid receptor binding of morphine-6-beta-D-glucuronide (M6G), morphine and [3H][D-Ala2,N-methylPhe4-Glyol5]enkephalin (DAMGO) were determined in neonatal guinea pigs. Pontomedullary membranes specifically bound [3H]DAMGO, which was displaced by M6G and morphine. The KI for M6G and morphine were 15.1 nM and 5.0 nM, respectively, and did not change between day 3 and day 7 after birth. KD for [3H]DAMGO binding was constant (1.1nM), however Bmax increased from 62.2 to 88.3 fmol/mg protein between days 3 and 7 (P < 0.01). This 42% increase in mu receptors may play a role in the increased potency of M6G respiratory effects for guinea pigs during the first week after birth.

Topics: Animals; Animals, Newborn; Brain Stem; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Enkephalins; Guinea Pigs; Morphine; Morphine Derivatives; Receptors, Opioid, mu

Modification of pharmacological effects of morphine by its glucuronides has been recently reported. Morphine-6-glucuronide (M6G) is a more potent opioid agonist than morphine, whereas morphine-3-glucuronide (M3G) has no opioid effects and has been suggested to be an antagonist of morphine's antinociceptive and respiratory depressive effects. This study addressed the metabolic effects of direct central nervous system administration of M3G and its interaction with the hyperglycemic effects of M6G. Hormonal and whole body glucose metabolic effects of M3G, M6G, and M3G + M6G ICV administration were studied in conscious unrestrained chronically catheterized rats. Whole body glucose kinetics were assessed with a primed constant intravenous infusion of 3[3H]glucose in rats injected intracerebroventricularly (ICV) with H2O (5 microliters), M3G (1 microgram), M6G (1 microgram), or M3G (1 microgram) + M6G (1 microgram). A significant rise in plasma glucose level was observed after ICV injection of M6G (28%), and M3G + M6G (41%), but not after M3G as compared to time-matched H2O control. Early increases in the rate of glucose appearance (Ra) and whole body glucose utilization (Rd) were observed (58% and 48%, respectively) 30 min after M3G + M6G administration, whereas the increases after M6G injection were progressive and reached values 47% higher than basal 180 min after injection. M3G administration enhanced the M6G induced increase in plasma glucose level (+21%), Ra (+29%), Rd (+26%), and plasma lactate level (+21%). Though no significant hormonal change was observed in H2O, M3G, and M6G injected animals, the combination of M3G + M6G resulted in a significant increase in circulating catecholamine levels with no alterations in plasma corticosterone, insulin, and glucagon.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Blood Glucose; Glycogen; Hormones; Injections, Intraventricular; Kinetics; Liver Glycogen; Male; Morphine Derivatives; Muscles; Rats; Rats, Sprague-Dawley

In 34 cancer patients treated with chronic slow-release oral morphine, plasma and cerebrospinal fluid (CSF) minimum steady-state concentrations of morphine (M), morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were determined by high-performance liquid chromatography (HPLC). Both plasma and CSF morphine, M3G and M6G, concentrations were linearly related to dose of morphine. At steady state, the mean +/- SEM CSF/plasma morphine concentration ratio was 0.8 +/- 0.1. In plasma and CSF, the mean steady-state concentrations of M3G and M6G substantially exceeded those of morphine where the mean CSF M/M3G/M6G ratio was 1:47:5 (weight basis), 1:34:4 (molar basis) and the mean plasma ratio was M/M3G/M6G 1:150:23 (weight basis), 1:109:17 (molar basis). The mean M3G and M6G concentrations in CSF at steady state were 15-18% of those found in plasma. Pain relief, evaluated by a visual analogue scale (VAS), did not correlate with the CSF M3G concentrations or with the M3G/M ratio. Since CSF M6G concentrations were high, M6G could, however, contribute to pain relief. We conclude that after oral administration of slow-release morphine, there is a significant passage of the morphine glucuronide metabolites to the CSF and that the M3G and M6G metabolites in CSF are in the concentration range where they may have an influence on analgesia.

Topics: Administration, Oral; Analgesics, Opioid; Delayed-Action Preparations; Dose-Response Relationship, Drug; Humans; Lumbosacral Region; Morphine; Morphine Derivatives; Neoplasms; Pain

A high-performance liquid chromatography (HPLC) method has been developed for the determination of morphine and its main metabolites, morphine-6-glucuronide (M-6-G) and morphine-3-glucuronide (M-3-G), in plasma or cerebrospinal fluid. Samples were extracted using on-line solid-phase extraction followed by reversed-phase HPLC with fluorescence detection. Recoveries of 20 ng morphine and morphine glucuronides in plasma were over 95%. The limit of detection using 400 microliters of a biological matrix was 0.85, 3.4 and 1.0 ng/ml of M-3-G, M-6-G and morphine, respectively. Inter- and intra-day assay precision was better than 10%. The main advantages of the present described method are increased recoveries (> 95%) and a high degree of automation allowing a high speed in routine analysis. The time required for the fully automated analysis of one sample was less than 26 min.

Topics: Automation; Chromatography, High Pressure Liquid; Humans; Morphine; Morphine Derivatives; Reproducibility of Results; Sensitivity and Specificity

Topics: Analgesics; Drug Resistance; Humans; Morphine; Morphine Derivatives

The pharmacokinetics of 30 mg nicomorphine after rectal administration with a suppository are described in 8 patients under combined general and epidural anaesthesia. No nicomorphine or 6-mononicotinoylmorphine could be detected in the serum. Morphine appeared almost instantaneously with a lag-time of 8 min and had a final elimination half-life of 1.48 +/- 0.48 h. Morphine was metabolized to morphine-3-glucuronide and morphine-6-glucuronide. These glucuronide conjugates appeared after a lag-time of 12 min and the half-life of these two glucuronide conjugates was similar: about 2.8 h (P > 0.8). The glucuronide conjugate of 6-mononicotinoylmorphine was not detected. In the urine only morphine and its glucuronides were found. The renal clearance value for morphine was 162 ml.min-1 and for the glucuronides 81 ml.min-1. This study shows that administration of a suppository with 30 mg nicomorphine gives an excellent absolute bioavailability of morphine and its metabolites of 88%. The lipid-soluble prodrug nicomorphine is quickly absorbed and immediately hydrolysed to morphine.

Topics: Administration, Rectal; Adult; Biological Availability; Drug Interactions; Female; Half-Life; Humans; Injections, Intravenous; Kidney; Middle Aged; Morphine; Morphine Derivatives; Nicotinic Acids

Morphine (M), morphine 3-glucuronide (M3G) and morphine 6-glucuronide (M6G) were subcutaneously administered at 10 mg/kg in three groups of six awake rats. A transverse microdialysis probe was implanted in the brain cortex and dialysates were collected every 30 minutes for a period of 4 hours. Dialysates were measured by two different opiate radioimmunoassays. Maximum brain opiate concentrations, 41 +/- 10 ng/ml (M), 147 +/- 27 ng/ml (M3G), 177 +/- 43 ng/ml (M6G), were reached at the same Tmax, 0.75 h, and elimination half-lives ranged from 0.99 to 0.81 h for the 3 compounds. Kinetic parameters confirmed that penetration and elimination rates in the extracellular space of the rat brain cortex for the 2 hydrophilic M metabolites were similar to those of M. These results indicate for the first time that, in spite of their structural differences, glucuronide metabolites of M are capable of crossing the blood-brain-barrier (BBB) at the same rate as morphine does, but in higher amount.

Topics: Animals; Blood-Brain Barrier; Cerebral Cortex; Male; Microdialysis; Morphine; Morphine Derivatives; Radioimmunoassay; Rats; Rats, Sprague-Dawley

In premature neonates (25-34 weeks gestation) who were given morphine intravenously during the first 24 h of life, only morphine, and morphine-3-glucuronide (M3G) were detected in plasma obtained after a 2-hour loading infusion, but morphine-6-glucuronide (M6G) could also be quantified following 24 h of continuous infusion. M3G/morphine and M6G/morphine plasma concentration ratios increased significantly with increasing birth weight. However, the M6G/M3G plasma concentration ratio decreased with increasing birth weight (and gestational age), thus providing the first indication in vivo of the differential development of uridinediphosphate glucuronosyltransferases in humans.

Topics: Birth Weight; Female; Gestational Age; Humans; Infant, Newborn; Infant, Premature; Kinetics; Male; Morphine; Morphine Derivatives

Morphine-6-beta-D-glucuronide (M6G) is an active metabolite of morphine. In a previous study, M6G depressed respiration in the neonatal guinea pig, becoming more potent with aging, a finding that is confirmed in the current study. After s.c. injection, M6G is absorbed into plasma, crosses the blood-brain barrier and is present in the central nervous system at the time of maximal M6G-induced ventilatory depression. No hydrolysis of M6G to morphine is detected in either plasma or brain tissue by high-performance liquid chromatography. About 30% more M6G is in plasma in 3-day-old than in 7-day-old pups after drug administration (P < .05). Mean brain concentrations of M6G are 12% higher on day 3 than day 7, but the difference is not statistically significant. Brain-to-plasma ratios of M6G do not differ after 5 or 15 mg/kg of M6G or with age (mean ratio = 0.037). Brain drug concentration is a linear function of plasma drug levels (r2 = 0.84), suggesting M6G crosses the blood brain barrier by diffusion. Differential systemic absorption or central nervous system distribution of M6G cannot explain enhanced respiratory depression with aging. Morphine-3-beta-D-glucuronide (M3G) also crossed the blood-brain barrier, but is less permeable than M6G (mean brain-to-plasma ratio = 0.022). Contrary to reports in the literature, M3G at a dose of 75 mg/kg, does not stimulate respiration in this study. Morphine administration to neonatal guinea pigs produces measurable plasma and brain levels of M6G and M3G.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Animals, Newborn; Brain; Diffusion; Guinea Pigs; Morphine; Morphine Derivatives; Respiration; Solubility

Recent studies have suggested that morphine-3-glucuronide (M3G) may antagonize the analgesic effects of morphine and morphine-6-glucuronide (M6G). To investigate this hypothesis, steady-state concentrations of morphine, M6G and M3G in serum and cerebrospinal fluid (CSF) were measured in 11 patients receiving chronic morphine therapy (9 orally and 2 subcutaneously) for treatment of cancer-related pain. All patients appeared to have morphine-resistant pain and had elected to proceed to intrathecal bupivacaine or percutaneous cordotomy. Morphine, M6G and M3G concentrations were measured by high-performance liquid chromatography. The concentrations (median and range) for morphine, M6G and M3G in serum were 193 (14-1086) nmol/l, 847 (210-4113) nmol/l and 4553 (1324-24035) nmol/l, respectively, while in CSF concentrations of morphine, M6G and M3G were 200 (21-1461) nmol/l, 115 (30-427) nmol/l and 719 (249-3252) nmol/l, respectively. Median molar ratios of M6G/morphine and M3G/morphine in serum were 3.79 and 22.1, respectively, while in CSF the same ratios were 0.42 and 2.39, respectively. Median molar ratios of M3G/M6G in serum and CSF were 5.84 and 6.61, respectively. The median molar ratios for CSF/serum distribution of morphine, M6G and M3G were 1.23, 0.12 and 0.14, respectively. Thus, despite their relatively poor ability to penetrate into the CSF, the high serum concentrations of M6G and M3G resulted in substantial concentrations of these metabolites in the CSF. Nevertheless, M3G/M6G ratios in our morphine-resistant patients were similar to published values in patients with well-controlled pain, suggesting that the hypothesis that M3G plays a major role in morphine-resistance is not correct.

Topics: Adult; Aged; Chromatography, High Pressure Liquid; Drug Resistance; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain

An original, sensitive, and specific high-performance liquid chromatographic (HPLC) assay was developed for the quantitation of morphine and its two major metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), in human plasma and cerebrospinal fluid (CSF) and in rat plasma, using hydromorphone as the internal standard. Solid-phase extraction was used to separate morphine and its glucuronide metabolites from plasma constituents. Extraction efficiencies of morphine, M3G, and M6G from human plasma samples (0.5 ml) were 84, 87, and 88%, respectively. Extraction efficiencies of morphine, M3G, and M6G did not differ significantly (p > 0.05) between human plasma and CSF or rat plasma. Morphine, M3G, M6G, and hydromorphone were separated on a 10 mu C8 Resolve radially compressed cartridge using a mobile phase comprising methanol:acetonitrile:phosphate buffer, (0.0125M pH 7.5; 10:10:80), in which 11 mg/L of cetyltrimethylammonium bromide (cetrimide) was dissolved. Quantitation was achieved using a single electrochemical detector at ambient temperature (23 degrees C). Standard curves were linear over the ranges 0.020-2.190, 0.027-2.709, and 0.027-0.542 microM for morphine, M3G, and M6G, respectively. Lower limits of detection for morphine, M3G, and M6G in human plasma and CSF samples (0.5 ml) were 0.020, 0.027, and 0.027 microM, respectively. Corresponding lower limits of detection in rat plasma (0.1 ml) were 0.102, 0.135, and 0.135 microM, respectively. Intraassay precision for low and high concentrations of morphine, M3G, and M6G were < 23 and < 8% respectively. Similarly, interassay accuracy for low and medium concentrations of morphine, M3G, and M6G were < 17% and were < 9% for high concentrations.

Topics: Animals; Chromatography, High Pressure Liquid; Electrochemistry; Humans; Morphine; Morphine Derivatives; Rats; Reproducibility of Results; Sensitivity and Specificity

In patients with renal failure, morphine may cause prolonged narcosis and respiratory depression. Accumulation of the pharmacologically active metabolite morphine-6-glucuronide (M-6G) may explain this effect of morphine in patients with renal failure. After a single oral dose, morphine and its conjugates were measured in the plasma and the cerebrospinal fluid (CSF) in patients with renal failure.. Eight patients with normal renal function and six patients with renal failure requiring dialysis were studied after operation under spinal anesthesia. Plasma and CSF concentrations of morphine, morphine-3-glucuronide (M-3G), and M-6G were measured by high-pressure liquid chromatography every 4 h for 24 h after an oral dose of 30 mg morphine.. The area under morphine plasma concentration-time curve from 0 to 24 h increased from 38 +/- 4 ng.ml-1 x h in patients with normal renal function to 110 ng.ml-1 x h in those with renal failure (P < 0.01). In patients with renal failure, plasma concentrations of M-3G and M-6G were higher at 4 h and remained at an increased level until the end of the study. The peak CSF concentration of morphine at 8 h was similar in those with renal failure or normal renal function, 1.8 +/- 0.4 and 2.0 +/- 0.6 ng.ml-1 respectively. M-3G and M-6G in CSF reached a maximum at 12 h in patients with normal renal function, whereas in those with renal failure the concentrations gradually increased so that the highest concentrations were observed at 24 h. At 24 h, CSF M-6G concentration was 15 times greater in patients with renal failure than in those with normal renal function.. We conclude that M-3G and M-6G readily cross the blood-brain barrier in patients with normal renal function or with renal failure. In patients with renal failure, the retention of plasma M-6G induces a progressive accumulation of this active metabolite in CSF; this accumulation may explain the increased susceptibility to morphine in patients with renal failure.

Topics: Administration, Oral; Aged; Aged, 80 and over; Blood-Brain Barrier; Body Weight; Humans; Kidney; Middle Aged; Morphine; Morphine Derivatives; Renal Insufficiency

1. By means of continuous cystometry in normal, unanaesthetized rats, the effects on micturition of intrathecally (i.t.) administered morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), the two main metabolites of morphine, were studied and compared with those of i.t. morphine. 2. Both M6G (0.01, 0.1, and 0.5 microgram) and M3G (5 micrograms) were found to have significant effects on micturition. Like morphine (0.1, 0.5, and 10 micrograms), M6G was able to inhibit the micturition reflex, and produce urinary retention and dribbling incontinence in a dose-dependent manner. The potency of M6G for inhibiting micturition was approximately 10 times higher than that of morphine, and the duration of its effect was longer. All effects of M6G could be reversed by naloxone. 3. M3G (5 micrograms) facilitated the micturition reflex, resulting in decreases in bladder capacity and micturition volume, and an increase in spontaneous contractile activity. Pretreatment with naloxone (10 micrograms), which by itself had no effect on micturition, enhanced the facilitatory effects of M3G. In addition, M3G tended to counteract the inhibitory effects of both morphine and M6G on micturition. M3G (5 micrograms) also produced an excitatory behavioural syndrome. 4. It is concluded that in rats, i.t. M3G has excitatory effects on micturition and behaviour, probably not mediated via opioid receptors. I.t M6G has a potent inhibitory effect on micturition mediated by stimulation of opioid receptors. It may have effects on somatosensory afferent input in lower doses than those required for effects on micturition.

Topics: Animals; Behavior, Animal; Dose-Response Relationship, Drug; Female; Injections, Spinal; Morphine; Morphine Derivatives; Naloxone; Rats; Rats, Sprague-Dawley; Urinary Bladder; Urination

Morphine or morphine-6-glucuronide either alone or in combination with morphine-3-glucuronide was administered intrathecally to rats. Antinociceptive effects were evaluated with the tail flick and the hot plate tests. Motor function was tested using the rotarod test. Estimated ED50 from the dose-response curves for morphine and morphine-6-glucuronide showed about a 30 times more potent antinociceptive effect of morphine-6-glucuronide compared with morphine. Morphine-3-glucuronide had no antinociceptive effect. Simultaneous administration of morphine-3-glucuronide 5.0 micrograms did not show any significant effect on antinociception induced by morphine 1.0 microgram or morphine-6-glucuronide 0.05 microgram.

Topics: Analgesics; Animals; Dose-Response Relationship, Drug; Injections, Spinal; Male; Morphine; Morphine Derivatives; Pain Measurement; Postural Balance; Rats; Rats, Wistar; Spinal Cord

An isocratic high-performance liquid chromatographic method has been developed for the determination of morphine, codeine, normorphine, morphine 3-glucuronide and morphine 6-glucuronide in plasma using a diol column and diode-array detection. Samples were extracted using solid-phase extraction with recoveries in excess of 90%. The limit of determination was 1 ng/ml for morphine, codeine and morphine 3-glucuronide, and 10 ng/ml for normorphine and morphine 6-glucuronide. Inter- and intra-day precision were better than 10%.

Topics: Chromatography, High Pressure Liquid; Codeine; Humans; Hydrogen-Ion Concentration; Morphine; Morphine Derivatives; Solvents

Morphine pharmacokinetics were studied in 17 premature neonates (26-34 weeks' gestation) after intravenous infusion during the first 24 hours of life. Infants received either standard dose morphine that comprised of a 100 micrograms/kg/hour loading infusion for 2 hours followed by a maintenance infusion of 12.5 micrograms/kg/hour, or a high dose of 200 micrograms/kg/hour for 2 hours followed by 50 micrograms/kg/hour. Mean plasma concentrations of morphine (SD) after 2 and 24 hours were 99 (12.9) and 96.4 (3.2) ng/ml, and 184.2 (37.7) and 319 (71.2) ng/ml for the standard and high dose regimens, respectively. Morphine-3-glucuronide plasma concentrations achieved about 20% and 80% of morphine values at 2 and 24 hours respectively. Morphine-6-glucuronide could not be detected at 2 hours, but attained 20-25% of morphine plasma concentrations by 24 hours. The population mean morphine clearance was 2.4 ml/min/kg, the elimination half life was 8.75 hours and the volume of distribution was 1.82 1/kg. High plasma concentrations of morphine appeared to be well tolerated. Although mean arterial blood pressure decreased during the first six hours of treatment, this was not statistically significant; two infants experienced transient muscle rigidity, but no evidence of seizures was noted. There appears to be no clinical advantage in using the high dose regimen.

Topics: Blood Pressure; Drug Administration Schedule; Female; Half-Life; Humans; Infant, Newborn; Infant, Premature; Infant, Premature, Diseases; Infusions, Intravenous; Male; Metabolic Clearance Rate; Morphine; Morphine Derivatives; Respiration, Artificial

The pharmacokinetics of morphine and its glucuronide metabolites were investigated in three groups of patients with kidney failure (nondialyzed, receiving dialysis, and transplantation) and compared with a group of normal healthy volunteers. Patients in all three renal groups were undergoing surgical procedures (nondialyzed group undergoing arteriovenous fistula formation, dialysis group undergoing placement of a peritoneal dialysis catheter, and the transplant group undergoing live donor kidney transplant). A sensitive, specific high-performance liquid chromatographic assay was used to quantitate morphine, morphine-3-glucuronide, and morphine-6-glucuronide. Patients with kidney failure had a significantly increased morphine area under the curve (AUC) compared with control subjects. There was also an increase in the metabolites morphine-3-glucuronide and morphine-6-glucuronide that was severalfold greater than the increase in morphine AUC. This metabolite accumulation was reversed by kidney transplantation, providing an elegant confirmation on the role of the kidney in morphine pharmacology.

Topics: Adult; Humans; Kidney Failure, Chronic; Kidney Transplantation; Metabolic Clearance Rate; Middle Aged; Morphine; Morphine Derivatives; Peritoneal Dialysis

Thirty-five cancer patients, treated with chronic epidural morphine, were assayed for plasma and cerebrospinal fluid (CSF) minimum steady-state concentrations (Css min) of morphine (M), morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) by high performance liquid chromatography (HPLC). A linear dose-concentration relationship was found for the 3 substances in plasma and for morphine and M3G in CSF. The mean +/- S.E.M. CSF/plasma morphine ratio was 158 +/- 43. In CSF, the concentrations of morphine exceeded those of the metabolites substantially and, normalized to morphine, the mean CSF M/M3G/M6G ratio was 1:0.05:0.02. In plasma, the metabolite concentrations were higher than the parent drug and the plasma M/M3G/M6G ratio was 1:12:3. The mean M3G and M6G concentrations in CSF were 40-60% of those found in plasma. Indication of cerebral formation of M3G was found in 1 patient. Pain relief, evaluated by a visual analogue scale (VAS), did not correlate with the CSF M3G concentrations or with the M3G/M ratio. CSF M6G concentrations were low and did not contribute to any detectable analgesia. We conclude that after epidural administration of morphine, the M3G and M6G metabolites in CSF are low compared to unchanged morphine and seem to have little influence on analgesia. However, the fact that a significant passage of the glucuronide metabolites occurs to the CSF may indicate a role in morphine analgesia after other routes of administration.

Topics: Analgesia, Epidural; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Humans; Morphine; Morphine Derivatives; Neoplasms; Pain Measurement; Pain, Intractable

The glucuronidation of morphine was investigated in 10 premature neonates (postnatal age < 24 h at initiation of treatment) following 24 h of therapy (2 h loading infusion, followed by a constant rate infusion). Morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were measured in plasma obtained at 24 h in all babies. Plasma concentrations of M3G and M6G correlated significantly with morphine concentration (P < 0.01 in both cases), and with each other (P < 0.001), suggesting that the capacity for morphine glucuronidation in premature neonates is not saturated at the infusion rates used in this study. M3G/morphine and M6G/morphine plasma concentration ratios were independent of morphine infusion rates (P > 0.05) and morphine plasma concentrations (P > 0.05), providing further evidence of linear kinetics. However, M3G/morphine and M6G/morphine plasma concentration ratios increased significantly with increasing birth weight (P < 0.05 in both cases). This probably reflects increase in liver weight with increasing birth weight. Although morphine glucuronidation is deficient in premature neonates, significant concentrations of the respiratory stimulant M3G are achieved rapidly (20% of morphine plasma concentrations at 2 h). At this time, the respiratory depressant M6G could not be detected.

Topics: Birth Weight; Female; Humans; Infant, Newborn; Infant, Premature; Male; Morphine; Morphine Derivatives

Morphine, morphine-6-glucuronide (M6G), morphine-3-glucuronide (M3G) and normorphine were analysed with high performance liquid chromatography in plasma and urine, collected over 72 h after administration of single intravenous 5 mg and oral 20 mg doses of morphine to 7 healthy volunteers. Systemic plasma clearance of morphine was on average 21.1 +/- 3.4 ml/min/kg (1.27 +/- 0.20 L/h/kg), volume of distribution was 2.9 +/- 0.8 L/kg and oral bioavailability was 29.2 +/- 7.2%. Clearance of morphine to form M3G and M6G comprised 57.3% and 10.4%, respectively, and renal clearance comprised 10.9% of total systemic plasma clearance; hence, more than one-fifth of a dose (20.8%) remained as unidentified residual clearance. On the basis of the area under the plasma concentration-time curves determined after oral and intravenous administration, the ratios of M6G:morphine were 3.6 +/- 1.2 and 0.7 +/- 0.3, respectively. The corresponding figures for M3G:morphine were 29.9 +/- 6.8 and 7.7 +/- 1.4. Differences in metabolic ratios between the parenteral and oral routes could be attributed solely to differences in morphine concentrations as evidenced both by plasma concentrations and amounts excreted in urine. An oral:parenteral potency ratio of 1:3 may, thus, be due to differences in circulating amounts of morphine since the proportions of an administered dose found as M6G and M3G after administration by both routes were equal. A major finding was a slowly declining terminal phase of morphine and metabolites that was evident both in plasma and in urinary excretion versus time curves, where the half-lives of morphine, M3G and M6G were 15.1 +/- 6.5 h, 11.2 +/- 2.7 h and 12.9 +/- 4.5 h, respectively. The terminal half-life of normorphine was 23.9 +/- 10.1 h after oral administration. Comparison of oral with intravenous excretion curves showed that a greater part of morphine and metabolites were excreted during the slowly declining phase after the oral dose than the intravenous dose, which is highly suggestive of enterohepatic cycling. The renal clearance of M6G and morphine was seen to exceed creatinine clearance, possibly due to an active secretion process.

Topics: Administration, Oral; Adult; Enterohepatic Circulation; Female; Humans; Injections, Intravenous; Male; Middle Aged; Morphine; Morphine Derivatives

The plasma concentrations and renal clearance values of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were determined in 11 adult cancer patients maintained on a long term oral morphine dosage (10 to 100mg every 4h). Concentrations in plasma and urine were determined by a specific high performance liquid chromatography assay. In this group of patients, whose creatinine clearance values ranged from 52 to 180 ml/min (3.12 to 10.8 L/h), average steady-state plasma concentrations of morphine, M3G and M6G were related (p < 0.01) to the morphine dose per kilogram of bodyweight. The mean total urinary recovery as morphine, M3G and M6G was 74.6 +/- 26.5% of the dose. Renal clearance values for M3G and M6G were closely related (r2 = 0.80; p < 0.0005). It was not possible to detect a relationship between the renal clearance of morphine, M3G and M6G, and that of creatinine. The renal tubular handling of all 3 compounds showed wide interindividual variation, and there was evidence of either net renal tubular secretion or reabsorption. There was no apparent relationship between plasma morphine and M6G concentrations and pain relief.

Topics: Adult; Aged; Aged, 80 and over; Chromatography, High Pressure Liquid; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain, Intractable; Regression Analysis

Intra-articular morphine (5 mg in 25 ml) was administered to patients for post-operative analgesia following arthroscopic knee surgery. At various time intervals, 30 min to 4 h post morphine, venous blood samples were taken in order to determine plasma levels of morphine and its primary metabolites, morphine-3-glucuronide and morphine-6-glucuronide. Measurable amounts of morphine and morphine-3-glucuronide were found in the plasma of 7/10 patients whereas morphine-6-glucuronide was detected in only 2/10 patients. The plasma levels of morphine were lower than that regarded sufficient for post-operative analgesia in all but two patients, indicating a possibility of peripheral analgesia. In addition, synovial biopsy samples were assayed for the presence of opioid binding sites. Tissue samples from 11 different patients were analysed and 6/11 exhibited specific binding of [3H]naloxone, indicating the presence of opioid binding sites/receptors. The receptor type (i.e. mu-, delta- or k-) is at present unknown. Taken together, these data provide evidence that locally administered opiates can act on specific opioid receptors in the synovium to mediate analgesia.

Topics: Adult; Analgesia; Arthroscopy; Female; Humans; Knee; Male; Morphine; Morphine Derivatives; Pain, Postoperative; Radioligand Assay; Receptors, Opioid; Synovitis

Codeine (30 mg phosphate) was metabolized by eight human volunteers to the following six metabolites: codeine-6-glucuronide 81.0 +/- 9.3 per cent, norcodeine 2.16 +/- 1.44 per cent, morphine 0.56 +/- 0.39 per cent, morphine-3-glucuronide 2.10 +/- 1.24 per cent, morphine-6-glucuronide 0.80 +/- 0.63 per cent, and normorphine 2.44 +/- 2.42 per cent. Two out of eight volunteers were unable to O-dealkylate codeine into morphine and lack therefore the cytochrome P450 IID6 isoenzyme. The half-life of codeine was 1.47 +/- 0.32 h, that of codeine-6-glucuronide 2.75 +/- 0.79 h, and that of morphine-3-glucuronide 1.71 +/- 0.51 h. The systemic clearance of codeine was 2280 +/- 840 ml min-1, the renal clearance of codeine was 93.8 +/- 29.8 ml min-1, and that of codeine-6-glucuronide was 122 +/- 39.2 ml min-1. The plasma AUC of codeine-6-glucuronide is approximately 10 times higher than that of codeine. Protein binding of codeine and codeine-6-glucuronide in vivo was 56.1 +/- 2.5 per cent and 34.0 +/- 3.6 per cent, respectively. The in vitro protein binding of norcodeine was 23.5 +/- 2.9 per cent; of morphine, 46.5 +/- 2.4 per cent; of normorphine, 23.5 +/- 3.5 per cent; of morphine-3-glucuronide, 27.0 +/- 0.8 per cent; and of morphine-6-glucuronide, 36.7 +/- 3.8 per cent.

Topics: Adult; Codeine; Female; Half-Life; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Protein Binding

Topics: Codeine; Morphine; Morphine Derivatives; Reproducibility of Results; Spectrophotometry, Ultraviolet

Topics: Chromatography, High Pressure Liquid; Codeine; Humans; Infant; Morphine; Morphine Derivatives; Optics and Photonics

Topics: Analgesics; Animals; Morphine Derivatives; Rats; Respiratory Mechanics

Plasma morphine concentrations were measured in five cancer patients receiving long-term epidural morphine administration. Peak concentrations were observed within 1 h of dosage and concentrations then declined biexponentially. Plasma morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) concentrations were measured in two patients and plasma M3G concentrations were observed to be much higher than plasma M6G and morphine concentrations. Peak plasma M6G concentrations occurred within 1.0 h of dosing and plasma M6G concentrations then remained higher than plasma morphine concentrations.

Topics: Analgesia, Epidural; Chromatography, High Pressure Liquid; Humans; Male; Morphine; Morphine Derivatives; Neoplasms; Pain, Intractable; Spectrometry, Fluorescence

The metabolism of morphine was studied in seven fullterm neonates and five infants receiving a continuous infusion of morphine. All the patients had detectable plasma concentrations of morphine 3-glucuronide (M3G) and 10 had detectable concentrations of morphine 6-glucuronide (M6G). The mean plasma clearance of morphine was 20.1 ml min-1 kg-1 in neonates and 23.4 ml min-1 kg-1 in the group as a whole. The M3G/morphine ratio (7.3) was higher than that previously reported for preterm neonates (5.0) but lower than that reported for children (23.9).

Topics: Chromatography, High Pressure Liquid; Humans; Infant; Infant, Newborn; Infant, Premature; Morphine; Morphine Derivatives; Spectrometry, Fluorescence

In the capacity of an initial study both, the half-lives of morphine and its metabolites morphine-3-glucuronide and morphine-6-glucuronide as well as the ratio of concentrations in the development of time using two different dosages were determined and shown by comparison. A bolus of 10 mg (10 micrograms) tritium-marked morphine was administered intravenously. Subsequently the half-lives of morphine, morphine-3-glucuronide and morphine-6-glucuronide in serum, saliva and urine were determined. To achieve this, morphine and its glucuronides were separated via HPLC and then quantified by measuring the radioactivity. In addition to the short half-lives of morphine and morphine-glucuronides long half-lives were found in the range of 12.6 to 20 hours in serum and urine. There was no positive evidence for glucuronides in saliva. In urine the morphine/glucuronide ratio showed a linear resp. exponential development dependent of dose.

Topics: Adult; Dose-Response Relationship, Drug; Humans; Male; Morphine; Morphine Derivatives; Pilot Projects; Substance Abuse Detection

To examine the manner in which morphine is metabolized in acutely ill premature infants, we measured the levels of morphine, morphine-3- and -6-glucuronides, and codeine in timed urine specimens and paired plasma specimens at 4 hours and 24 hours after a single dose of morphine in 16 preterm infants (less than 32 weeks of gestational age). A large amount of unmetabolized morphine was found in the urine in 13 (81.2%) of the 16 infants at 4 hours; in 12 of them, morphine was excreted even at 24 hours. Urinary morphine levels varied greatly; the coefficient of variation was 130% at 4 hours and 118% at 24 hours. Codeine was not found in any of the infants. In 10 (62.5%) of the 16 infants, at least one metabolite was found in either plasma or urine. Plasma and urinary levels of morphine conjugates also varied greatly among these 10 infants (coefficient of variation: 109% to 317%). All six infants (37.5%) who had no metabolites excreted large amounts of unmetabolized morphine in the urine for up to 24 hours. Birth weight, gestational age, postnatal age, systemic blood pressure, and other clinical or physiologic variables did not differ significantly between the 10 infants who had morphine conjugates and the six who did not. We conclude that (1) nearly two thirds of acutely ill preterm infants born at less than 32 weeks of gestational age conjugate morphine; (2) irrespective of their ability to produce morphine conjugates, preterm infants excrete large amounts of morphine unmetabolized, as late as 24 hours after a single dose; (3) morphine handling patterns are highly variable among premature infants, and no obvious factors account for the variability; and (4) such variability in morphine handling in general, and the production of the highly potent morphine-6-glucuronide in particular, could explain the variance in morphine pharmacokinetic measures and in the clinical responses to morphine during the newborn period.

Topics: Chromatography, High Pressure Liquid; Codeine; Female; Humans; Infant, Newborn; Infant, Premature, Diseases; Male; Morphine; Morphine Derivatives; Respiration, Artificial

The effects of the major morphine metabolites, morphine-3-glucuronide and morphine-6-glucuronide, on nociception were assessed by the tail-flick, hot-plate and writhing tests in the rat. Morphine-3-glucuronide (M3G) 1.1 x 10(-9) mol (0.5 micrograms) or saline was injected intracerebroventricularly (i.c.v.) or intrathecally (i.t.) followed by a second injection of 2.0 x 10(-10) mol (0.1 microgram) or 2.0 x 10(-11) mol (0.01 microgram) morphine-6-glucuronide (M6G) 10 min later. Administration of M3G (i.c.v.) significantly attenuated the antinociceptive effects of M6G in the hot-plate test. After i.t. administration, the antinociceptive effect of M6G in all three tests was significantly reduced in the M3G pretreated group compared to the group receiving saline. The ventilatory effects of 4.0 x 10(-9)-1.0 x 10(-8) mol (2-5 micrograms) M6G and 1.7-2.2 x 10(-8) mol (8-10 micrograms) M3G given i.c.v. were studied by a whole-body plethysmographic technique in halothane anaesthetized rats. Separate groups of rats received M3G followed by M6G injection or vice versa. In animals receiving M3G there was a prevention or attenuation of the M6G induced depression of respiratory frequency, tidal volume and minute ventilation compared to control groups receiving M6G in combination with saline. These results show that M3G may functionally antagonize the central antinociceptive effects as well as the ventilatory depression induced by M6G. Interestingly, M3G was more potent in antagonizing the M6G-induced analgesia after i.t. administration than that after i.c.v. administration, which may suggest that the spinal cord is more sensitive to the non-opioid excitatory effects of M3G than supraspinal structures.

Topics: Analgesics; Animals; Male; Morphine Derivatives; Rats; Rats, Inbred Strains; Respiration

The major metabolites of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), possess significant pharmacological properties. Whilst both metabolites bind to mu-opioid binding sites, M6G is a potent agonist whereas M3G antagonizes some of the effects of morphine and M6G. An inter-species comparison of in vitro hepatic morphine processing was performed. The results showed that not all species were able to produce M6G whereas all those tested did produce M3G. Guinea-pig liver produced the greatest amounts of M6G and was therefore chosen as a model to study morphine glucuronidation in further detail. Inclusion of the detergent Brij 58 (0.33 mg/mg protein) and Mg2+ (15 mM) in the standard assay incubation gave optimal production of both M3G and M6G by guinea-pig liver homogenates. A number of metal ions were investigated for their ability to inhibit glucuronidation of morphine in both the 3- and 6-positions. Some metal ions, namely Cu+, Cu2+ and Cd2+, were able to inhibit the production of M3G without affecting glucuronidation at the 6-position. Taken together, these data provide further evidence for the existence of UDP-glucuronosyltransferase isoenzymes responsible for the metabolism of morphine. In addition these isoenzymes can be differentially modulated and therefore it is possible to alter the ratio of M3G:M6G formed during in vitro metabolic studies.

Topics: Animals; Cadmium; Cadmium Chloride; Chlorides; Copper; Glucuronosyltransferase; Guinea Pigs; Ions; Kinetics; Liver; Metals; Morphine; Morphine Derivatives

1. The relationships between renal creatinine clearance and the renal clearances of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were studied in fifteen intensive-care patients who were receiving morphine sulphate by constant intravenous infusion and who had diverse renal function. 2. An arterial blood sample was collected before and after a 4-5 h urine collection. Plasma and urine concentrations of morphine, M3G and M6G were measured by h.p.l.c. Plasma binding of all three compounds in drug-free plasma from healthy volunteers was determined by ultrafiltration. Measured renal creatinine clearance (CLCr,meas) was calculated from plasma and urinary creatinine concentrations (from h.p.l.c.). Also, creatinine clearance was predicted (CLCr,pred) from routine laboratory determination of plasma creatinine (Jaffe method). 3. There were significant linear relationships (P less than 0.001) between CLCr,meas and the renal clearances of morphine, M3G and M6G. The unbound renal clearance of morphine exceeded CLCr,meas (P less than 0.002) while the unbound renal clearances of M3G and M6G did not differ from CLCr,meas (P greater than 0.5). 4. In ten of the patients who received a constant infusion of morphine for at least 6 h, the dose-normalised plasma concentrations of M3G and M6G increased with decreasing CLCr,pred. Significant (P less than 0.001) relationships were observed between the reciprocal of CLCr,pred and the dose-normalised plasma concentrations of M3G and M6G. 5. The results indicate the importance of renal function in determining the renal clearances and plasma concentrations of M3G and M6G during intravenous infusion with morphine in intensive-care patients.

Topics: Adolescent; Adult; Aged; Creatinine; Female; Humans; Infusions, Intravenous; Intensive Care Units; Kidney; Male; Metabolic Clearance Rate; Middle Aged; Morphine; Morphine Derivatives

Morphine 6-glucuronide, but not morphine 3-glucuronide, is a highly potent opiate receptor agonist. In fact, there is converging evidence that much of the analgesic effect occurring after morphine treatment in humans is due to this metabolite rather than to the parent drug. Yet glucuronides as a rule are considered as highly polar metabolites unable to cross the blood-brain barrier and rapidly excreted by the urinary and/or biliary routes. Here, we report that morphine 6-glucuronide, and to a lesser extent morphine 3-glucuronide, are far more lipophilic than predicted, and in fact not much less lipophilic than morphine itself. Force-field and quantum mechanical calculations indicate that the two glucuronides can exist in conformational equilibrium between extended and folded forms. The extended conformers, because they efficiently expose their polar groups, must be highly hydrophilic forms predominating in polar media such as water; in contrast, the folded conformers mask part of their polar groups, thus being more lipophilic and likely to predominate in media of low polarity such as biological membranes.

Topics: Calorimetry; Computer Graphics; Indicators and Reagents; Models, Molecular; Molecular Conformation; Morphine Derivatives

An isocratic high-performance liquid chromatographic method has been developed for the determination of morphine, morphine-3-glucuronide, morphine-6-glucuronide and codeine in plasma, urine and cerebrospinal fluid. The use of an efficient solid-phase extraction procedure together with a forward optical scanning detector allows a detection limit of 500 pg/ml. The method was evaluated by examination of biological samples taken from newborn infants following the intravenous administration of morphine sulfate.

Topics: Chromatography, High Pressure Liquid; Codeine; Humans; Infant, Newborn; Injections, Intravenous; Morphine; Morphine Derivatives; Reproducibility of Results

After intracerebroventricular administration of morphine in four cancer patients, cerebrospinal fluid (CSF) was analyzed by two morphine radioimmunoassays (RIA), liquid chromatography (LC) and radioreceptor assay (RRA) to evaluate the presence of morphine metabolites. Immunoreactive morphine-like substances were detected by differential RIA's. The maximum concentrations of these compounds were achieved 3 hours after drug administration. These concentrations, according to the specificity of the antiserum, represent a mixture of several metabolites in which only morphine 3-glucuronide(M 3-G) and morphine 6-glucuronide (M 6-G) were identified by LC, and M 6-G by LC-RRA. These results confirm that brain is able to metabolize morphine to inactive (M 3-G) or more potent (M 6-G) derivatives.

Topics: Chromatography, Liquid; Humans; Injections, Intraventricular; Male; Morphine; Morphine Derivatives; Pain, Intractable; Radioimmunoassay; Radioligand Assay

This article describes a high-performance liquid chromatography (HPLC) method for the simultaneous determination of morphine (M) and its principal metabolites morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G), and normorphine (NM) in plasma. All four compounds are extracted from plasma using a C8 solid-phase extraction column, separated by reverse-phase HPLC on a C18 analytical column, and detected by spectrofluorometry at 210 nm excitation wavelength. The method takes advantage of the compounds' native fluorescence, so that derivitization is not required. Samples have been quantified over a concentration range of 25-100 ng/ml M and NM, 50-200 ng/ml M3G, and 100-300 ng/ml M6G, using nalorphine (500 ng/ml) as internal standard. Within-run and between-run errors were less than 10% for morphine and less than 13% for all the metabolites. The lower limit of quantitation for morphine is 10 ng/ml. The accuracy of the method was confirmed by including quality controls fitted to the standard curves of each compound. The assay described in this article represents a simplification of previous versions of the method, which included cumbersome extraction procedures and multiple detectors. For the first time, an internal standard has been employed. The assay is reliable and easy to use and can be performed in any therapeutic drug monitoring laboratory.

Topics: Chromatography, High Pressure Liquid; Fluorometry; Humans; Morphine; Morphine Derivatives

Species difference in glucuronidation of morphine was studied using mice, rats, guinea pigs and rabbits in vivo and in vitro. Morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G) were determined by high-performance liquid chromatography. M-3-G was the major urinary metabolite of morphine in all these animal species. However, a remarkable species difference was observed in the urinary excretion of the M-6-G. Excretion ratios of the M-3-G to M-6-G were approximately 4:1 and 50:1 in guinea pigs and rabbits, respectively. The urinary excretion of M-6-G in mice and rats was too small to be determined. On the other hand, the ratios of uridine diphosphate-glucuronyltransferase (UDPGT) activities toward 3- and 6-hydroxyl groups of morphine in liver microsomes of mice, rats, guinea pigs and rabbits were approximately 300:1, 90:1, 4:1 and 40:1, respectively. Ratios of two morphine UDPGT activities in the liver microsomes of guinea pigs and rabbits, thus, reflected those of urinary excretion of morphine glucuronides.

Topics: Animals; Biotransformation; Biphenyl Compounds; Chromatography, High Pressure Liquid; Glucuronates; Glucuronosyltransferase; Guinea Pigs; In Vitro Techniques; Liver; Male; Mice; Mice, Inbred Strains; Microsomes, Liver; Morphine; Morphine Derivatives; Nitrophenols; Rabbits; Rats; Rats, Inbred Strains; Species Specificity

Morphine and its major metabolites, morphine-3-glucuronide and morphine-6-glucuronide, were given intracerebroventricularly (i.c.v.) to rats. The antinociceptive effects were assessed in the tail-flick and hot-plate tests as well as the writhing test. Ventilatory effects were studied in halothane-anaesthetized rats. Based on calculated ED50 values, morphine-6-glucuronide was approximately 200 times more potent that morphine itself in the tail-flick and hot-plate tests. In the writhing test the difference in ED50 was approximately 9-fold. Morphine and morphine-6-glucuronide administered i.c.v. induced dose-related decreases in minute ventilation in the dose range 2.7 x 10(-9)-1.3 x 10(-7) mol. The dose-response curve for minute ventilation was steeper for morphine-6-glucuronide than for morphine. Morphine-6-glucuronide was approximately 10 times more potent than morphine in depressing minute ventilation. Morphine-6-glucuronide reduced both tidal volume and respiratory frequency, while morphine reduced only the tidal volume. Morphine-3-glucuronide, in contrast, increased both tidal volume and respiratory frequency, causing an increase in minute ventilation. Apnoea was elicited after the highest doses of morphine-6-glucuronide but not of morphine. The potency difference for depression of minute ventilation between morphine-6-glucuronide and morphine corresponded well to the difference in the writhing test but not to the potency difference in the tail-flick or hot-plate tests. The ventilatory depression induced by morphine and morphine-6-glucuronide was readily reversed by naloxone, while the hyperventilation caused by morphine-3-glucuronide was slightly potentiated by the opioid antagonist. Naloxone pretreatment completely blocked the ventilatory depression induced by morphine-6-glucuronide. These results show that the potent ventilatory depression induced by morphine-6-glucuronide is related to its antinociceptive effects in rats. Furthermore, the fact that morphine-3-glucuronide stimulated ventilation and that morphine had a more shallow ventilatory dose-response curve compared to morphine-6-glucuronide may indicate that morphine-3-glucuronide is a functional antagonist of the depressive effects of morphine and morphine-6-glucuronide on ventilation.

Topics: Analgesics; Animals; Dose-Response Relationship, Drug; Injections, Intraventricular; Male; Morphine Derivatives; Naloxone; Rats; Rats, Inbred Strains; Reaction Time; Respiration

A convenient and sensitive analytical method for determination of plasma morphine and its metabolites in cancer patients was established using HPLC with a column-switching technique. Sample plasma which has been deproteinized with trichloroacetic acid is injected onto a precolumn, then the compounds of interest are preferentially introduced into the analytical column for separation and detection after washing out the unnecessary plasma components from the precolumn. Detection was simultaneously performed with coulometry for unchanged morphine and morphine-6-glucuronide and with UV analysis for morphine-3-glucuronide. Analytical recoveries were greater than 99% for these compounds, and the averaged coefficients of within-day or between-day variation did not exceed 5.5%. Detection limits were 0.2 ng/mL for morphine, 0.5 ng/mL for morphine-6-glucuronide, and 10 ng/mL for morphine-3-glucuronide. Correlation between the previously reported solid extraction method and this method was satisfactory in plasma samples after administration of morphine.

Topics: Chromatography, High Pressure Liquid; Humans; Morphine; Morphine Derivatives; Neoplasms; Palliative Care

Morphine was assayed using a simple two step solvent extraction--acid back extraction sample preparation method, coupled with normal phase high-performance liquid chromatography (HPLC) and dual electrode coulometric detection. HPLC is performed with a 1.0 M Tris-methanol (5:95) mobile phase with subtle pH adjustments to separate morphine and internal standard from any interfering compounds. The use of normal phase HPLC (silica column) substantially reduces problems from interfering lipophilic substances sometimes encountered with reverse phase HPLC following solvent extraction and which would otherwise require more time-consuming sample preparation. Dual electrode detection further improves the selectivity for morphine and gives excellent sensitivity (0.5 ng mL-1), reproducibility and stability for automated sample injection. This method has proven suitable for pharmacokinetic studies of morphine.

Topics: Animals; Body Fluids; Chromatography, High Pressure Liquid; Colorimetry; Hydromorphone; Infusions, Intravenous; Kidney; Liver; Morphine; Morphine Derivatives; Sheep

1. Metabolites of codeine were determined by use of h.p.l.c. in urine of male mice, rats, guinea pigs and rabbits injected with 10 mg codeine/kg subcutaneously. 2. In 24 h urines of these species, unchanged codeine, codeine glucuronide, free morphine, and morphine-3-glucuronide were as follows: mice, 6.8, 1.6, 0.8 and 7.6% dose; rats, 1.6, 0.2, 4.3 and 23.9% dose; guinea pigs, 1.6, 39.8, 0.2 and 1.6% dose; rabbits, 2.2, 24.5, 1.3 and 17.9% dose. Urinary excretion of morphine-6-glucuronide was 0.7% dose in guinea pigs, 1.9% in rabbits, and not detectable in mice and rats. Norcodeine was found only in the urine of mice. 3. These results indicate that codeine is metabolized in all four species by glucuronidation and by oxidative N- and O-demethylation, but the quantitative excretions of metabolites were quite different in different species.

Topics: Animals; Chromatography, High Pressure Liquid; Codeine; Guinea Pigs; Male; Mice; Morphine; Morphine Derivatives; Rabbits; Rats; Rats, Inbred Strains; Species Specificity

1. A 43-year-old male developed acute kidney failure due to ethylene glycol poisoning. He was treated with bicarbonate to combat metabolic acidosis, ethanol as an antimetabolite and haemodialysis to remove the glycol and its toxic metabolites. He was kept on a respirator and sedated with morphine. Peritoneal dialysis was given for 36 d. Following sedation with morphine for 11 d, the patient was given naloxone and then extubated. The antidote had to be continued for 14 d to prevent respiratory depression, until kidney function improved. 2. Only morphine-6-glucuronide (M-6-G) was found in the plasma and CSF at concentrations which might explain the opioid effects observed in the patient during the days after the cessation of morphine treatment. The ratio of the area under the concentration-time curve (AUC) of morphine-3-glucuronide (M-3-G) to M-6-G was 2:1. The elimination half-lives of M-3-G and M-6-G were 55 and 82 h, respectively. The clearance data indicate that most of the glucuronides were eliminated by peritoneal dialysis during renal failure. 3. The data suggest that M-6-G exerts opioid effects and is retained in acute kidney failure. Morphine should therefore not be used preferentially as a sedative/analgesic in pronounced kidney failure.

Topics: Acute Kidney Injury; Adult; Ethylene Glycol; Ethylene Glycols; Humans; Male; Morphine; Morphine Derivatives

The pharmacokinetic parameters of morphine, morphine-6-glucuronide, and morphine-3-glucuronide were studied after single-dose morphine administration by five different routes. The quantitative significance of the active metabolite morphine-6-glucuronide was assessed, and the effects of novel dosing forms on morphine metabolism and distribution were examined. After administration of intravenous morphine the morphine-6-glucuronide plasma AUC exceeded that of morphine. After administration of oral morphine very low morphine levels were observed--the morphine-6-glucuronide plasma AUC exceeded that of morphine by a factor of 9:1. Sublingual, buccal, and sustained-release buccal morphine tablet administration resulted in delayed absorption, with attenuation and delay of peak morphine and metabolite levels. Morphine bioavailability and morphine glucuronide production were not altered.

Topics: Administration, Oral; Adult; Delayed-Action Preparations; Half-Life; Humans; Injections, Intravenous; Metabolic Clearance Rate; Morphine; Morphine Derivatives; Tablets

1. The oral and intravenous kinetics of morphine were investigated in seven cirrhotic patients with a history of encephalopathy. The plasma concentrations of morphine and its metabolites morphine-3 (M3G) and morphine-6 (M6G) were measured by h.p.l.c. 2. The mean terminal elimination half-life of morphine was 4.2 h (95% CI 3.6-4.8) the mean volume of distribution was 4.1 l kg-1 (95% CI 2.9-5.4) and the mean plasma clearance was 11.4 ml min-1 kg-1 (95% CI 8.1-14.7). The mean oral bioavailability was 101% (95% CI 56-147). 3. The plasma clearance of morphine was significantly lower, its terminal elimination half-life longer and its oral bioavailability greater in the cirrhotic patients compared with patients with normal liver function. The metabolic ratio M3G/morphine was significantly lower in the cirrhotic patients than in control subjects after oral dosing, but did not differ after intravenous dosing. 4. The average urinary recoveries of morphine plus M3G and M6G were 49.9% after i.v. and 57.7% after oral administration. There were no statistically significant differences in the urinary recovery between the two routes of administration or between the cirrhotic patients and controls. 5. Specific changes in the EEG pattern could not be detected after intravenous dosage. 6. The metabolism of morphine is impaired significantly in patients with severe cirrhosis. Clinically important findings were a high oral bioavailability and a long elimination half-life. These findings call for cautious dosing of oral and intravenous morphine in patients with severe end stage liver disease.

Topics: Administration, Oral; Aged; Biological Availability; Electroencephalography; Female; Half-Life; Humans; Injections, Intravenous; Liver Cirrhosis; Male; Middle Aged; Morphine; Morphine Derivatives

A method for the fast analysis of morphine (M), normorphine (NM), morphine-3- and -6-glucuronides (M3G and M6G) and codeine (C) is described which has the advantages of sensitivity, speed and specificity. Dihydrocodeine and heroin can also be assayed. The method is based on extraction of the opiates from serum, plasma and cerebrospinal fluid using reversed-phase solid-phase extraction columns, followed by reversed-phase high-performance liquid chromatography with native fluorescence detection. The extraction step provides greater than 95% recovery, and the response of the detection system is linear from 0.5 to beyond 750 ng. The method allows analysis of M, NM, M3G, M6G and C. No other drugs have been found to interfere with the assay. The assay offers a quick, cheap and reliable method of specifically determining morphine and its metabolites, including the potent M6G, from a small sample volume; this will be of advantage to both clinician and basic scientist.

Topics: Chromatography, High Pressure Liquid; Codeine; Fluorescence; Humans; Microchemistry; Morphine; Morphine Derivatives; Quality Control

There is growing evidence that renally-impaired patients receiving morphine therapy are at greater risk of developing opiate toxicity, due to the accumulation of an active metabolite, morphine-6-glucuronide (M6G), which is usually excreted by the kidneys. This study examined the relationships between morphine dosage, renal function, and trough plasma concentrations of morphine and its glucuronide metabolites in 21 patients (aged mean: 68.5 years: 11 males) receiving either oral or subcutaneous morphine for terminal cancer pain. The median daily morphine dosages (mg.kg-1) were: orally 1.87 (range 0.37-6.82) and subcutaneously 1.64 (range 0.22-3.60). The median plasma concentrations of morphine, morphine-3-glucuronide (M3G), and M6G (ng.ml-1) were: 36.0, 1035.2, and 142.3, respectively. The plasma concentrations of morphine, M3G and M6G were each significantly related to the daily morphine dosage (n = 21, Spearman r = 0.79, 0.91, and 0.88 respectively). Accumulation of the morphine glucuronides was dependent on renal function. The plasma concentrations of M3G and M6G, when divided by the morphine concentration, were significantly related to the calculated creatinine clearance of the patient. Patients receiving oral morphine had higher plasma concentration ratios of glucuronide/morphine than those receiving subcutaneous therapy, presumably due to first-pass glucuronidation. The results of this study confirm that accumulation of the pharmacologically active M6G is related to renal function, which probably explains the observation that morphine dosage requirements are generally reduced in patients with renal impairment.

Topics: Aged; Aged, 80 and over; Creatinine; Female; Humans; Kidney; Kidney Function Tests; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain, Intractable

The kinetics of morphine, morphine-6-glucuronide (M6G), and morphine-3-glucuronide (M3G) were studied in a 56-year-old female with lung cancer. Long-term treatment with morphine intrathecally 28 mg every 6 h was used for pain control. Cerebrospinal fluid (CSF) concentrations of morphine were high with an elimination half-life of 2.1 h. The plasma/CSF ratios for M6G and M3G were 1:0.8 and 4:1, respectively, suggesting that M6G penetrates the blood-brain barrier more easily than M3G. The low CSF concentrations indicate that M6G played hardly any major analgetic role in the patient studied.

Topics: Female; Humans; Injections, Spinal; Middle Aged; Morphine; Morphine Derivatives; Osmolar Concentration; Time Factors

One hundred fifty-one patients with chronic cancer pain were studied during chronic treatment with oral morphine. Plasma concentrations of morphine and metabolites (M3G and M6G) were measured. The ratio of plasma morphine to metabolites was not affected by dose. Generalized linear interactive modeling analysis using morphine dose, age, sex, renal and hepatic dysfunction, and concomitant medication as explanatory variables accounted for 70% of the variance in plasma concentrations of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G). Increasing morphine dose was a significant factor for increased plasma concentrations of morphine, M3G, and M6G. Other significant factors were: age greater than 70 years (increased M3G and M6G plasma concentrations), plasma creatinine greater than 150 mumol/L (increased M3G and M6G plasma concentrations), male sex (decreased morphine and M6G plasma concentrations), raised creatinine plus coadministration of tricyclic antidepressants (increased M3G plasma concentrations), ranitidine (increased morphine plasma concentrations), and raised creatinine plus coadministration of ranitidine (increased M6G plasma concentrations).

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain; Sex Factors

In this study, morphine-3-glucuronide (M3G), the major plasma and urinary metabolite of morphine, was shown to be a potent antagonist of morphine analgesia when administered to rats by the intra-cerebroventricular (i.c.v.) route. The antagonism of morphine analgesia was observed irrespective of whether i.c.v. M3G (2.5 or 3.0 micrograms) was administered 15 mins prior to or 15 mins after i.c.v. morphine (20 micrograms). When M3G (10mg) was administered intraperitoneally (i.p.) to rats 30-40 mins prior to morphine (1.5mg i.p.), the analgesic response was significantly reduced compared to administration of morphine (1.5mg i.p.) alone. It was further demonstrated that i.c.v. M3G (2.0 micrograms) antagonized the analgesic effects of subsequently administered i.c.v. morphine-6-glucuronide (0.25 micrograms).

Topics: Analgesia; Animals; Drug Administration Routes; Male; Morphine; Morphine Derivatives; Pain Measurement; Rats; Rats, Inbred Strains

The formation of morphine glucuronides is enantio- and regioselective in rats and humans. In rat liver microsomes, natural (-)-morphine formed only the 3-O-glucuronide, whereas the unnatural (+)-morphine formed glucuronides at both the 3-OH and 6-OH positions, with the 6-O-glucuronide being the principal product. In human liver microsomes, both the 3-OH-and 6-OH positions were glucuronidated with each of the enantiomers, with the 3-O-glucuronide being the major product with (-)-morphine, and the 6-OH position preferred with the (+)-enantiomer. By using a series of biochemical and biological situations such as induction by xenobiotics, ontogeny, selective inhibition and genetic deficiencies, which are considered to be diagnostic of UDP-glucuronosyltransferase heterogeneity, we determined that two UDP-glucuronosyltransferase isoenzymes were responsible for the glucuronidation of morphine in rat liver. One isoenzyme (the so-called "morphine UDP-glucuronosyltransferase") was responsible for the glucoronidation at the (-)-3-OH and (+)-6-OH positions of morphine, whereas the other formed only the (+)-morphine-3-glucuronide. Evidence from enzyme induction and the genetically deficient deficient Gunn rat suggested that bilirubin UDPGT may be responsible for the (+)-morphine-3-UDP-glucuronosyltransferase activity. In human kidney, glucuronidation of both (-)- and (+)-enantiomers at the 6-OH position was deficient, whereas the activity at the 3-OH positions was still present, which indicated the involvement of two UDP-glucuronosyltransferases in the glucuronidation of morphine in man, as well as rats.

Topics: Age Factors; Animals; Clofibrate; Enzyme Induction; Glucuronosyltransferase; Humans; In Vitro Techniques; Isoenzymes; Liver; Male; Morphine; Morphine Derivatives; Naphthaleneacetic Acids; Rats; Rats, Gunn; Rats, Inbred Strains; Stereoisomerism

The ventilatory effects of morphine-6-glucuronide (M-6-G) and morphine-3-glucuronide (M-3-G) were evaluated in awake dogs (n = 10). A fourth ventricle to cisterna magna perfusion (VCP) system was used for drug administration. This permitted a direct comparison of the dose/ventilatory response characteristics of these morphine metabolites to each other and to morphine and obviated the need to consider the blood-brain barrier delay that would complicate analysis of systemic dose versus ventilatory response relationships among these drugs. The dose/response pattern for morphine was taken from an earlier study in unanesthetized dogs where the identical mode of drug delivery as in the present report was employed. Morphine-3-glucuronide caused, if anything, a ventilatory stimulation (decreased PaCO2 and increased CO2 responsiveness) at the highest infusate concentration studied (50 micrograms/ml) and no significant ventilatory effects at infusate concentrations at or below 10 micrograms/ml. On the other hand, M-6-G produced a profound dose-dependent ventilatory depression. Significant increases in PaCO2 and diminution of CO2 responsiveness were observed even at the lowest infusate concentration evaluated (0.1 microgram/ml). When compared to morphine, M-6-G was found to be about five to ten times more potent as a ventilatory depressant drug. These results imply that M-6-G may play a significant role in the ventilatory depression accompanying systemic morphine administration.

Topics: Animals; Blood Pressure; Depression, Chemical; Dogs; Dose-Response Relationship, Drug; Injections, Intraventricular; Male; Morphine Derivatives; Pulmonary Gas Exchange; Respiration; Stimulation, Chemical

1. The metabolism of morphine was studied in 12 children and nine premature neonates on a continuous infusion of morphine (10-360 micrograms kg-1 h-1). 2. The mean plasma clearance of morphine was significantly higher in children than neonates (25.7 and 4.7 ml min-1 kg-1, respectively) (P less than 0.01). 3. All the neonates and children had detectable concentrations of morphine-3-glucuronide (M3G) in plasma. All the children and five neonates had detectable concentrations of morphine-6-glucuronide (M6G) in plasma or urine. 4. The M3G/morphine ratios in plasma and urine, and M6G/morphine ratios in urine were significantly higher in children than neonates (P less than 0.01), suggesting that morphine glucuronidation capacity is enhanced after the neonatal period. 5. There was no difference in the M3G/M6G ratio in children and neonates, indicating a parallel development of both glucuronidation pathways.

Topics: Adolescent; Child; Child, Preschool; Humans; Infant, Newborn; Infusions, Intravenous; Morphine; Morphine Derivatives

Topics: Biotransformation; Humans; Lung; Morphine; Morphine Derivatives

The effects of aging on the disposition of morphine and its metabolites have been investigated in 10 middle-aged patients (36 to 55 years of age) undergoing lower abdominal or body surface surgery, and compared with 10 elderly patients (65 to 83 years of age) undergoing similar surgery. All patients received 10 mg morphine sulphate pentahydrate IV over 30 seconds as part of a balanced anesthetic technique. Peripheral venous blood samples were collected to 180 min, and plasma concentrations of morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) were assayed by differential radioimmunoassay. There were no differences between the two groups for morphine elimination half-life (middle-aged patients, 129 min; elderly patients, 162 min), mean residence time (154 and 207 min), and apparent volume of distribution at steady state (116 and 107 l). However, clearance was significantly greater in the younger patients (853 vs. 559 ml/min; p less than 0.02). The area under the curve (AUC0-180) for M3G and M6G were similar in the two patient groups, as were the peak metabolite concentrations and times to peak concentrations. M6G has been shown in both animals and humans to exert analgesic properties. Despite the reduced clearance of the parent drug, there was an unaltered AUC for M6G, presumed due to the greater decrease in glomerular filtration rate seen during anesthesia in the elderly patient. This phenomenon may result in enhanced analgesic efficacy from a given dose of morphine in the elderly patient.

Topics: Adult; Aged; Aged, 80 and over; Aging; Anesthesia, Intravenous; Dose-Response Relationship, Drug; Female; Humans; Liver Circulation; Male; Middle Aged; Morphine; Morphine Derivatives; Renal Circulation; Surgical Procedures, Operative

The influence of renal failure on the disposition of morphine and its metabolites was studied in nine patients with end-stage renal failure undergoing transplantation, and compared with five healthy anaesthetized patients. All patients received morphine sulphate pentahydrate 10 mg i.v. over 30 s, as part of a balanced anaesthetic technique. Venous blood samples were collected for up to 24 h, and plasma concentrations of morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) assayed by a differential radioimmunoassay method. There were no differences between the two groups for morphine elimination half-life (renal failure: 290 min; anaesthetized controls: 286 min), or clearance (renal failure: 533 ml min-1; controls 741 ml min-1). However, the volume of distribution at steady state was greater in the control group (241 litre v. 141 litre; P = 0.002). The peak concentrations of M3G and M6G were greater in the renal transplant patients (P = 0.001 and P = 0.01, respectively), as were the AUC (0-24 h) (P = 0.002 and P = 0.002). M6G has been shown to possess analgesic properties in both man and experimental animals, and therefore the increased AUC for M6G may contribute to the prolonged effect seen with morphine when given to patients with impaired renal function.

Topics: Adult; Anesthesia, General; Half-Life; Humans; Kidney Failure, Chronic; Kidney Transplantation; Metabolic Clearance Rate; Middle Aged; Morphine; Morphine Derivatives

We report a case of long lasting respiratory depression after intravenous administration of morphine to a 7 year old girl with haemolytic uraemic syndrome. The plasma concentrations of the active metabolite M6G were more than 10 times those normally seen and the half-lives of M6G and morphine were prolonged.

Topics: Child; Depression, Chemical; Female; Hemolytic-Uremic Syndrome; Humans; Morphine Derivatives; Pain, Postoperative; Respiration Disorders

The effect of six different methods of blood sample preparation on concentrations of morphine (M), morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) have been investigated using a specific high performance liquid chromatography assay. No difference between glass or plastic tubes was seen in concentrations of M, M3G, or M6G; and no difference between plasma and serum in M and M6G concentrations. M3G concentrations, however, were significantly lower in plasma compared with serum. Heparin had no effect on M, M6G or M3G, whereas citrate in a glass tube produced consistently lower concentrations of M, M3G and M6G. Standardization of sample collection using plasma samples in plastic heparin tubes is recommended for future studies.

Topics: Chromatography, High Pressure Liquid; Humans; Morphine; Morphine Derivatives; Specimen Handling

Plasma and urine concentrations of morphine, morphine-3-glucuronide and morphine-6-glucuronide were measured in seven patients after orthotopic liver transplantation. After a single i.v. bolus of morphine sulphate 10 mg a biexponential decay was observed. Although the distribution and elimination half-lives for morphine were similar to those described in previous studies, a greater total apparent volume of distribution was observed. This was reflected in a greater plasma clearance of morphine than has been reported previously. The concentration of morphine glucuronides remained increased 24 h after administration of morphine; the clinical significance of this remains to be established. The metabolism of morphine was virtually complete, with 4.5% unchanged morphine recovered in urine 24 h after drug administration.

Topics: Adult; Female; Humans; Liver Circulation; Liver Transplantation; Male; Middle Aged; Morphine; Morphine Derivatives

The primary site for the metabolism of morphine has been the subject of controversy for some time. We studied morphine metabolism during the anhepatic phase of orthotopic liver transplantation in seven adult patients. After injection of morphine 10 mg at the beginning of this phase, the plasma and urinary concentrations of unchanged morphine, morphine-3-glucuronide, morphine-6-glucuronide and normorphine were measured by high pressure liquid chromatography. Small but measurable concentrations of morphine metabolites were found in the plasma and urine whilst there was no functional liver tissue in the body. Morphine metabolism increased markedly when the new donor liver was reperfused. This suggests that, in these patients, the liver is the primary site for metabolism of morphine.

Topics: Adult; Female; Humans; Intraoperative Period; Liver; Liver Transplantation; Male; Middle Aged; Morphine; Morphine Derivatives

The kinetics of morphine were studied during balanced anaesthesia in 10 patients undergoing lower abdominal or body surface surgery, and compared with those obtained in nine awake patients receiving morphine i.v. for the relief of chronic non-cancer pain. All patients received morphine sulfphate pentahydrate 10 mg i.v. over 30 s. Venous blood samples were collected for up to 180 min, and plasma concentrations of morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) assayed by a differential radioimmunoassay technique. There were no differences between groups with respect to the elimination half-life (awake group: 207 min; anaesthetized group: 153 min), volume of distribution at steady state (awake: 147 litre; anaesthetized: 128 litre), or clearance (awake: 587 ml min-1; anaesthetized: 766 ml min-1). Peak concentrations of M3G were similar in the two groups, but the peak concentration of M6G was greater in the anaesthetized patients. The AUC for M3G and M6G (0-180 min) also were greater in the anaesthetized patients, presumably as a result of decreases in renal blood flow and glomerular filtration rate during halothane anaesthesia.

Topics: Adult; Anesthesia, General; Half-Life; Humans; Metabolic Clearance Rate; Middle Aged; Morphine; Morphine Derivatives

The bioavailability of oral controlled release morphine tablets (MST, Napp Laboratories) and oral morphine sulphate in aqueous solution (MSS) was compared in 10 patients with advanced cancer. Serum samples were analysed for morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) using a specific HPLC assay. The relative bioavailability of morphine with MST was significantly less than that with MSS (mean 80%, range 50-110%) although there was no difference between the formulations in the relative availability of M3G and M6G. There was no significant difference between the formulations in the serum concentration of morphine at 12 h. The mean ratios morphine: M6G:M3G (comparing areas under the serum concentration-time curves) were 1:9:56. There was a highly significant linear relationship between the dose administered and AUC for morphine, M3G and M6G after MSS; and for morphine after MST. Median tmax for morphine was 0.5 h with MSS and 2.5 h with MST; for M3G 1.5 h with MSS and 3.0 h with MST; and for M6G 1.5 h with MSS and 3.25 h with MST. A secondary peak of unconjugated morphine, which may represent enterohepatic circulation, was seen in several patients 2-4 h after administration of elixir and 4-6 h after administration of MST.

Topics: Adult; Aged; Biological Availability; Delayed-Action Preparations; Female; Humans; Male; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain, Intractable

The 3- and the 6-glucuronides of morphine have been examined in binding studies and in vivo. The 3-glucuronide had poor affinity in all binding studies whereas the 6-glucuronide potently labeled mu, but not delta or kappa receptors with affinities similar to morphine. Microinjections of the 3-glucuronide directly into the periaqueductal gray were without effect. The 6-glucuronide, on the other hand, was up to 20-fold more potent than morphine following microinjections in the same region. High doses of the 6-glucuronide produced profound seizure activity. All 6-glucuronide actions were sensitive to the opiate antagonist naloxone.

Topics: Animals; Biotransformation; Male; Microinjections; Morphine; Morphine Derivatives; Rats; Rats, Inbred Strains; Receptors, Opioid; Receptors, Opioid, delta; Receptors, Opioid, mu

Topics: Analgesia; Humans; Morphine; Morphine Derivatives

The analysis of morphine, morphine-3-glucuronide (M-3-G) morphine-6-glucuronide (M-6-G) by differential radioimmunoassay using iodinated label and three different antisera is described. These methods were used to measure concentrations of morphine and its conjugated metabolites in human plasma, over a 3-h period, following a single 10 mg intravenous dose. In 13 patients peak concentrations of M-3-G (739 nmol/L +/- 73.7 SEM) were approximately 10 times greater than those of M-6-G (71.3 nmol/L +/- 8.6 SEM). Times to reach these peaks were similar for both metabolites. Decay of morphine from plasma followed a biexponential pattern with a mean terminal half-life of 59.3 min (+/- 8.1 SEM, n = 11). Accurate determination of the half-lives of the glucuronides was not possible due to the short sampling period, but M-6-G seemed to have a similar half-life to morphine, while M-3-G was eliminated more slowly.

Topics: Aged; Female; Half-Life; Humans; Kinetics; Male; Middle Aged; Morphine; Morphine Derivatives; Quality Control; Radioimmunoassay; Spectrophotometry

Plasma morphine, morphine-3-glucuronide and morphine-6-glucuronide concentrations were measured (HPLC) in two children immediately before orthotopic liver transplantation and in the postoperative period. Both of the patients had end-stage hepatic failure, but one also had impaired renal function before operation and was oliguric during and after surgery. Both patients metabolized morphine rapidly, but in the patient with renal failure, the metabolites appeared to accumulate. Morphine has active metabolic products and the accumulation of these in patients with impaired renal function may lead to a clinically observable prolongation of its effect.

Topics: Child, Preschool; Diuresis; Female; Humans; Kidney; Kinetics; Liver Diseases; Liver Transplantation; Male; Morphine; Morphine Derivatives; Postoperative Period

Topics: Humans; Kidney Failure, Chronic; Kinetics; Morphine; Morphine Derivatives

The kinetics of morphine and formation of the main metabolite, morphine-3-glucuronide (M3G) after single and intravenous doses of morphine were studied in six cancer patients and compared with the formation rate of M3G in vitro in microsomes isolated from liver biopsies obtained from the same patients at palliative laparotomy. The results showed that high formation rates of M3G in vitro in microsomes isolated from liver biopsies were associated both with high apparent oral clearance values and high M3G/morphine AUC (area under the concentration vs time curve) ratios as measured in vivo in the same patients. In accordance with previous results marked interindividual differences were seen in the kinetics of morphine; the oral bioavailability varied between 30 and 69% and the systemic plasma clearance between 18.6 and 34.0 ml min-1 kg-1. This variation correlated with the variation in morphine metabolism as assessed in vitro. In vivo, a high M3G/morphine AUC ratio predicted a high oral clearance. Hepatic UDP-glucuronyl transferase activity is thus an important determinant of the in vivo kinetics of orally administered morphine.

Topics: Administration, Oral; Aged; Glucuronates; Half-Life; Humans; In Vitro Techniques; Injections, Intravenous; Kinetics; Liver; Male; Microsomes, Liver; Middle Aged; Morphine; Morphine Derivatives; Neoplasms; Pain

The kinetics of morphine in the rhesus monkey after i.v. or oral administration including the hepatic extraction ratio determined directly in the portal and hepatic veins were compared with the glucuronidation of morphine in liver microsomes from the same animals. The plasma half-lives varied between 102 and 202 min and the apparent volume of distribution was 2.68 to 3.15 l X kg b.wt.-1. The systemic blood clearance (9.2-21.3 ml X min-1 X kg b.wt.-1) was in the same range as the estimated hepatic blood clearance (9.7-23.9 ml X min-1 X kg b.wt.-1). After i.v. administration, the blood concentrations of morphine-3-glucuronide ( M3G ) were 8 to 11 times higher than those of morphine. The molar blood concentration ratio between morphine-6-glucuronide and M3G was 0.04 or less. The ratio between the metabolite levels in blood was similar to the relative formation rates for M3G and morphine-6-glucuronide in liver microsomal preparations (less than .039). The intrinsic hepatic metabolic clearance of morphine as estimated from the apparent enzyme kinetic constants Vmax and Km for the formation of the major M3G metabolite was used to predict the hepatic extraction ratio. The predicted values of the hepatic extraction ratio (0.09-0.14) were, however, underestimates of the experimentally determined hepatic extraction ratio, which varied between 0.61 and 0.74. This indicates that unknown factors in the liver microsomal glucuronidation preclude the use of enzyme kinetics parameters obtained in vitro for the prediction of the hepatic extraction ratio of morphine. For some drugs that are oxidized it has been shown previously that such prediction from in vitro data is possible.

Topics: Animals; Female; In Vitro Techniques; Kinetics; Macaca mulatta; Microsomes, Liver; Morphine; Morphine Derivatives

Topics: Chromatography, High Pressure Liquid; Humans; Morphine; Morphine Derivatives; Neoplasms; Reference Values