Correction to: Comparative Study of the Dose-Dependence of OATP1B Inhibition by Rifampicin Using Probe Drugs and Endogenous Substrates in Healthy Volunteers.

There was a miscalculation of coproporphyrin I AUC0-24h in the published article (Volume 35, Number 7). After the correction of AUC0-24h, AUC ratio and R-square were re-calculated. Then, following corrections were made in the abstract, the body, Fig. 3, Fig. 4 and Table 2 in this article.

Comparative Study of the Dose-Dependence of OATP1B Inhibition by Rifampicin Using Probe Drugs and Endogenous Substrates in Healthy Volunteers.

PURPOSE: To evaluate association of the dose-dependent effect of rifampicin, an OATP1B inhibitor, on the plasma concentration-time profiles among OATP1B substrates drugs and endogenous substrates. METHODS: Eight healthy volunteers received atorvastatin (1 mg), pitavastatin (0.2 mg), rosuvastatin (0.5 mg), and fluvastatin (2 mg) alone or with rifampicin (300 or 600 mg) in a crossover fashion. The plasma concentrations of these OATP1B probe drugs, total and direct bilirubin, glycochenodeoxycholate-3-sulfate (GCDCA-S), and coproporphyrin I, were determined. RESULTS: The most striking effect of 600 mg rifampicin was on atorvastatin (6.0-times increase) and GCDCA-S (10-times increase). The AUC0-24h of atorvastatin was reasonably correlated with that of pitavastatin (r2 = 0.73) and with the AUC0-4h of fluvastatin (r2 = 0.62) and sufficiently with the AUC0-24h of rosuvastatin (r2 = 0.32). The AUC0-24h of GCDCA-S was reasonably correlated with those of direct bilirubin (r2 = 0.74) and coproporphyrin I (r2 = 0.78), and sufficiently with that of total bilirubin (r2 = 0.30). The AUC0-24h of GCDCA-S, direct bilirubin, and coproporphyrin I were reasonably correlated with that of atorvastatin (r2 = 0.48-0.70) [corrected]. CONCLUSION: These results suggest that direct bilirubin, GCDCA-S, and coproporphyrin I are promising surrogate probes for the quantitative assessment of potential OATP1B-mediated DDI.

Quantitative Analyses of the Influence of Parameters Governing Rate-Determining Process of Hepatic Elimination of Drugs on the Magnitudes of Drug-Drug Interactions via Hepatic OATPs and CYP3A Using Physiologically Based Pharmacokinetic Models.

Physiologically based pharmacokinetic models were constructed for hepatic organic anion-transporting polypeptides (OATPs) and cytochrome P450 3A (CYP3A) substrates (bosentan, repaglinide, clarithromycin, and simeprevir), a CYP3A probe substrate (midazolam), and selective inhibitors for OATPs (rifampicin) and CYP3A (itraconazole), although the role of OATPs in the hepatic uptake of clarithromycin is unclear. The pharmacokinetic data were obtained from our previous clinical drug-drug interaction (DDI) study. Parameters optimized from clinical PK data were confirmed to reproduce their blood concentrations in control phase. DDIs with rifampicin and itraconazole were simulated using in vivo Rdif (ratio of diffusional uptake to active uptake) and ß (the fraction of the sum of intrinsic clearances for metabolism and biliary excretion in all possible itineraries of intracellular drugs including basolateral efflux) estimated by static analyses based on the extended clearance concept, in vivo inhibition constant (Ki) for hepatic OATPs reported previously, and in vivo Ki for CYP3A determined from DDI data with midazolam and itraconazole. Sensitivity analyses showed the magnitudes of DDIs largely depended on Rdif and ß. In conclusion, our approach using physiologically based pharmacokinetic modeling showed that the rational estimation of parameters governing rate-determining process of hepatic elimination is critical to accurately predict DDI magnitudes involving OATPs/CYP3A inhibition.

A Clinical Cassette Dosing Study for Evaluating the Contribution of Hepatic OATPs and CYP3A to Drug-Drug Interactions.

PURPOSE: To demonstrate the relative importance of organic anion-transporting polypeptides (OATPs) and cytochrome P450 3A (CYP3A) in the hepatic elimination of substrate drugs. METHODS: A cocktail of subtherapeutic doses of bosentan, repaglinide, clarithromycin, darunavir, simeprevir, and midazolam (CYP3A probe) was administered orally to eight healthy volunteers. Rifampicin (OATP inhibitor; 600 mg, p.o.) and itraconazole (CYP3A inhibitor; 200 mg, i.v.) were coadministered with the cocktail in the second and third phases, respectively. Based on the extended clearance concept, in vivo ß values (fraction of metabolism plus biliary excretion among all the intracellular fates of drugs including basolateral efflux) and Rdif values (ratio of diffusional uptake to active uptake) were estimated. RESULTS: Rifampicin increased plasma AUCs of bosentan (×3.2), repaglinide (×1.9), clarithromycin (×1.9) and simeprevir (×7.2). Itraconazole increased those of clarithromycin (×2.3), simeprevir (×2.2) and midazolam (×3.7), which had relatively small ß values. The plasma AUC of bosentan (with relatively large ß and small Rdif) was dominated by OATP-mediated uptake. The AUC of simeprevir was also dominated by OATP-mediated uptake because of its small Rdif value. CONCLUSIONS: The DDI study clarified the rate-determining processes of OATP/CYP3A substrates. Our analyses provide valuable information for predicting complex drug-drug interactions involving multiple processes.