Abstract
A serious pharmacokinetic interaction between cerivastatin (CER) and gemfibrozil (GEM) has been reported. In the present study, we examined the inhibitory effects of GEM and its metabolites, M3 and gemfibrozil 1-O-β-glucuronide (GEM-1-O-glu), on the uptake of CER by human organic anion transporting polypeptide 2 (OATP2)-expressing cells and its metabolism in cytochrome P450 expression systems. Uptake studies showed that GEM and GEM-1-O-glu significantly inhibited the OATP2-mediated uptake of CER with IC50 values of 72 and 24 μM, respectively. They also inhibited the CYP2C8-mediated metabolism of CER with IC50 values of 28 and 4 μM, respectively, whereas M3 had no effects. GEM and GEM-1-O-glu minimally inhibited the CYP3A4-mediated metabolism of CER. The IC50 values of GEM and GEM-1-O-glu for the uptake and the metabolism of CER obtained in the present study were lower than their total, and not unbound, plasma concentrations. However, considering the possibly concentrated high unbound concentrations of GEM-1-O-glu in the liver and its relatively larger plasma unbound fraction compared with GEM itself, the glucuronide inhibition of the CYP2C8-mediated metabolism of CER appears to be the main mechanism for the clinically relevant drug-drug interaction. Previously reported clinical drug interaction studies showing that coadministration of GEM with pravastatin or pitavastatin, both of which are known to be cleared from the plasma by the uptake transporters in the liver, only minimally (less than 2-fold) increased the area under the plasma concentration-time curve of these statins, also supported our present conclusion.
Footnotes
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This study was supported in part by a grant-in-aid for Young Scientists (B) provided by the Ministry of Education, Culture, Sports, Science and Technology, Japan (Y.Sh.), a grant-in-aid for the Advanced and Innovational Research Program in Life Sciences from the Ministry of Education, Culture, Sports, Science and Technology, Japan (Y.Su.), and a Health and Labor Sciences Research grant from the Ministry of Health, Labor and Welfare, Japan, for the Research on Advanced Medical Technology (Y.Su.).
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doi:10.1124/jpet.104.068536.
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ABBREVIATIONS: GEM, gemfibrozil; CER, cerivastatin; DDI, drug-drug interaction; AUC, area under the plasma concentration-time curve; P450, cytochrome P450; UGT, uridine diphosphate glucuronosyltransferase; Ki, inhibition constant; GEM-1-O-glu, gemfibrozil 1-O-β-glucuronide; HPLC, high-performance liquid chromatography; IC50, concentration of inhibitor to produce a 50% reduction in the metabolism or transport; HLM, human liver microsome; Ab, antibody; TLC, thin-layer chromatography; CLuptake, uptake clearance.
- Received March 16, 2004.
- Accepted June 10, 2004.
- The American Society for Pharmacology and Experimental Therapeutics
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