rifampin and pitavastatin

Rosuvastatin and pitavastatin have been proposed as probe substrates for the organic anion-transporting polypeptide (OATP) 1B, but clinical data on their relative sensitivity and selectivity to OATP1B inhibitors are lacking. A clinical study was therefore conducted to determine their relative suitability as OATP1B probes using single oral (PO) and intravenous (IV) doses of the OATP1B inhibitor rifampicin, accompanied by a comprehensive in vitro assessment of rifampicin inhibitory potential on statin transporters.. The clinical study comprised of two separate panels of eight healthy subjects. In each panel, subjects were randomized to receive a single oral dose of rosuvastatin (5 mg) or pitavastatin (1 mg) administered alone, concomitantly with rifampicin (600 mg) PO or IV. The in vitro transporter studies were performed using hepatocytes and recombinant expression systems.. Rifampicin markedly increased exposures of both statins, with greater differential increases after PO vs. IV rifampicin only for rosuvastatin. The magnitudes of the increases in area under the plasma concentration-time curve were 5.7- and 7.6-fold for pitavastatin and 4.4- and 3.3-fold for rosuvastatin, after PO and IV rifampicin, respectively. In vitro studies showed that rifampicin was an inhibitor of OATP1B1 and OATP1B3, breast cancer resistance protein and multidrug resistance protein 2, but not of organic anion transporter 3.. The results indicate that pitavastatin is a more sensitive and selective and thus preferred clinical OATP1B probe substrate than rosuvastatin, and that a single IV dose of rifampicin is a more selective OATP1B inhibitor than a PO dose.

Topics: Administration, Intravenous; Administration, Oral; Adult; Area Under Curve; Cross-Over Studies; Drug Interactions; Female; Fluorobenzenes; Hepatocytes; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Liver-Specific Organic Anion Transporter 1; Male; Middle Aged; Organic Anion Transporters; Organic Anion Transporters, Sodium-Independent; Pyrimidines; Quinolines; Rifampin; Rosuvastatin Calcium; Solute Carrier Organic Anion Transporter Family Member 1B3; Sulfonamides; Young Adult

As an inhibitor of HMG-CoA reductase that catalyses the first step of cholesterol synthesis, pitavastatin undergoes little hepatic metabolism; however, it is a substrate of uptake and efflux transporters. Since pitavastatin is potentially co-administered with agents that affect transporter activities, the pharmacokinetics of pitavastatin was investigated on the effects of a single-dose rifampin in healthy volunteers.. Twelve Chinese healthy male volunteers took 4 mg pitavastatin orally with 150 ml water or with a single dose of 600 mg rifampin on separate occasions and the plasma concentrations of pitavastatin were measured over 48 h by HPLC-MS/MS.. A single dose of rifampin significantly increased the mean area under the plasma concentration-time curve(AUC)(0-48 h) and Cmax of pitavastatin by 573.5 %(95%CI, 373.3-773.7 %, p < 0.001) and 819.2 %(95 % CI, 515.4-1123.0 %, p < 0.001) respectively, while significantly decreased the t1/2 and CL/F of pitavastatin by 38.8 % (95 % CI, 18.2-59.4 %, p < 0.001) and 81.4 % (95 % CI, 75.0-87.7 %, p < 0.001) respectively.. Co-administration of pitavastatin with a single dose of rifampin resulted in a significant increase in plasma levels of pitavastatin in Chinese healthy subjects.

Topics: Adult; Cross-Over Studies; Drug Interactions; Healthy Volunteers; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Liver-Specific Organic Anion Transporter 1; Male; Organic Anion Transporters; Quinolines; Rifampin; Young Adult

Topics: Biological Transport; Humans; Liver; Membrane Transport Proteins; Quinolines; Rifampin

We developed a practical synthetic method for fluorine-18 (

Topics: Animals; ATP Binding Cassette Transporter, Subfamily G, Member 2; Blotting, Western; Chromatography, Thin Layer; Fluorine Radioisotopes; Liver; Male; Molecular Structure; Neoplasm Proteins; Organic Anion Transporters; Positron-Emission Tomography; Quinolines; Rats; Rats, Sprague-Dawley; Rifampin

Induction potentials of the pregnane X receptor (PXR) activator rifampin (RIF) on transporter genes [e.g., organic anion-transporting polypeptides (OATPs)] are still in its infancy or remain controversial in the field. The present investigations characterized changes in transporter gene expression by RIF in sandwich-cultured hepatocytes from multiple donors of human and cynomolgus monkey using real-time quantitative reverse transcription polymerase chain reaction method. Three-day treatment of RIF significantly induced CYP3A4 (∼60-fold induction), but not CYP1A2 and CYP2D6 genes. SLC51B was the most highly induced uptake transporter gene (>10-fold) in both human and monkey hepatocytes. A greater induction of CYP2C9 was observed in monkey hepatocytes than that in humans. ATP-binding cassette (ABC)B1 and ABCC2 were induced slightly above 2-fold in human and monkey hepatocytes and appeared to be dose-dependent. The induction of OATP and other transporter genes was generally less than 2-fold and considered not clinically relevant. SLCO2B1 was not detectable in monkey hepatocytes. To investigate in vivo OATP induction, RIF (18 mg/kg per day) was orally dosed to cynomolgus monkeys for 7 days. Pitavastatin and antipyrine were intravenously dosed before and after RIF treatment as exogenous probes of OATP and CYP activities, respectively. Plasma coproporphyrin-I (CP-I) and coproporphyrin-III (CP-III) were measured as OATP endogenous biomarkers. Although a significant increase of antipyrine clearance (CL) was observed after RIF treatment, the plasma exposures of pitavastatin, CP-I, and CP-III remained unchanged, suggesting that OATP function was not significantly altered. The results suggested that OATP transporters were not significantly induced by PXR ligand RIF. The data are consistent with current regulatory guidances that the in vitro characterization of transporter induction during drug development is not required. SIGNIFICANCE STATEMENT: Organic anion-transporting polypeptide (OATP) genes were not induced by rifampin in sandwich-cultured human and monkey hepatocytes OATP functions measured by OATP probe pitavastatin and endogenous marker coproporphyrins were not altered in monkeys in vivo by 7-day rifampin treatment. The data suggested that OATP transporters are unlikely induced by the pregnane X receptor ligand rifampin, which are consistent with current regulatory guidances that the in vitro characterization of OATP1B induction during drug development is n

Topics: Animals; Antipyrine; Area Under Curve; Cells, Cultured; Gene Expression; Hepatocytes; Humans; Macaca fascicularis; Male; Multidrug Resistance-Associated Protein 2; Organic Anion Transporters; Pregnane X Receptor; Quinolines; Rifampin; Species Specificity

Quantification of the fraction transported (f

Topics: Adult; Biological Transport; Cell Line; Cyclosporine; Drug Interactions; Female; HEK293 Cells; Hepatocytes; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Liver; Liver-Specific Organic Anion Transporter 1; Male; Membrane Transport Proteins; Middle Aged; Organic Anion Transporters, Sodium-Dependent; Quinolines; Rifampin; Solute Carrier Organic Anion Transporter Family Member 1B3; Symporters

This study aimed to construct a widely applicable method for quantitative analyses of drug-drug interactions (DDIs) caused by the inhibition of hepatic organic anion transporting polypeptides (OATPs) using physiologically based pharmacokinetic (PBPK) modeling. Models were constructed for pitavastatin, fluvastatin, and pravastatin as substrates and cyclosporin A (CsA) and rifampicin (RIF) as inhibitors, where enterohepatic circulations (EHC) of statins were incorporated. By fitting to clinical data, parameters that described absorption, hepatic elimination, and EHC processes were optimized, and the extent of these DDIs was explained satisfactorily. Similar in vivo inhibition constant (K

Topics: Antibiotics, Antitubercular; Computer Simulation; Cyclosporine; Drug Interactions; Enzyme Inhibitors; Fatty Acids, Monounsaturated; Fluvastatin; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Indoles; Liver; Models, Biological; Organic Anion Transporters; Pravastatin; Quinolines; Rifampin

Clopidogrel is reported to be associated with cerivastatin-induced rhabdomyolysis, and clopidogrel and its metabolites are capable of inhibiting CYP2C8 and OATP 1B1 in vitro. The objective of the present study was to identify the mechanism of clopidogrel-mediated drug-drug interactions (DDIs) on the pharmacokinetics of OATP1B1 and/or CYP2C8 substrates in vivo. A clinical cassette small-dose study using OATPs, CYP2C8, and OATP1B1/CYP2C8 probe drugs (pitavastatin, pioglitazone, and repaglinide, respectively) with or without the coadministration of either 600 mg rifampicin (an inhibitor for OATPs), 200 mg trimethoprim (an inhibitor for CYP2C8), or 300 mg clopidogrel was performed, and the area under the concentration-time curve (AUC) ratios (AUCRs) for probe substrates were predicted using a static model. Clopidogrel increased the AUC of pioglitazone (2.0-fold) and repaglinide (3.1-fold) but did not significantly change the AUC of pitavastatin (1.1-fold). In addition, the AUC of pioglitazone M4, a CYP2C8-mediated metabolite of pioglitazone, was reduced to 70% of the control by coadministration of clopidogrel. The predicted AUCRs using the mechanism-based inhibition of CYP2C8 by clopidogrel acyl-β-glucuronide were similar to the observed AUCRs, and the predicted AUCR (1.1) of repaglinide using only the inhibition of OATP1B1 did not reach the observed AUCR (3.1). In conclusion, a single 300 mg of clopidogrel mainly inhibits CYP2C8-mediated metabolism by clopidogrel acyl-β-glucuronide, but its effect on the pharmacokinetics of OATP1B1 substrates is negligible. Clopidogrel is expected to have an effect not only on CYP2C8 substrates, but also dual CYP2C8/OATP1B1 substrates as seen in the case of repaglinide.

Topics: Area Under Curve; Clopidogrel; Cytochrome P-450 CYP2C8; Dose-Response Relationship, Drug; Drug Interactions; Humans; In Vitro Techniques; Male; Platelet Aggregation Inhibitors; Quinolines; Rifampin; Ticlopidine; Trimethoprim