Prediction of the Overall Renal Tubular Secretion and Hepatic Clearance of Anionic Drugs and a Renal Drug-Drug Interaction Involving Organic Anion Transporter 3 in Humans by In Vitro Uptake Experiments □ S Takao Watanabe, Hiroyuki Kusuhara, Tomoko Watanabe, Yasuyuki Debori, Kazuya Maeda, Tsunenori Kondo, Hideki Nakayama, Shigeru Horita, Brian W. Ogilvie, Andrew Parkinson, Zhuohan Hu, and Yuichi Sugiyama Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, the University of Tokyo, Tokyo, Japan (Ta.W., H.K., To.W., Y.D., K.M., Y.S.); Department of Urology, Kidney Center, Tokyo Women’s Medical University, Tokyo, Japan (T.K., H.N., S.H.); XenoTech, LLC, Lenexa, Kansas (B.W.O., A.P.); and Research Institute for Liver Diseases (Shanghai) Co. Ltd., Shanghai, China (Z.H.) Received August 28, 2010; accepted February 23, 2011 ABSTRACT: The present study investigated prediction of the overall renal tu- bular secretion and hepatic clearances of anionic drugs based on in vitro transport studies. The saturable uptake of eight drugs, most of which were OAT3 substrates (rosuvastatin, pravastatin, pitavastatin, valsartan, olmesartan, trichlormethiazide, p-amino- hippurate, and benzylpenicillin) by freshly prepared human kidney slices underestimated the overall intrinsic clearance of the tubular secretion; therefore, a scaling factor of 10 was required for in vitro-in vivo extrapolation. We examined the effect of gemfibrozil and its metabolites, gemfibrozil glucuronide and the carboxylic metabolite, gemfibrozil M3, on pravastatin uptake by human kidney slices. The inhibition study using human kidney slices suggests that OAT3 plays a predominant role in the renal uptake of prava- statin. Comparison of unbound concentrations and K i values (1.5, 9.1, and 4.0 M, for gemfibrozil, gemfibrozil glucuronide, and gem- fibrozil M3, respectively) suggests that the mechanism of the in- teraction is due mainly to inhibition by gemfibrozil and gemfibrozil glucuronide. Furthermore, extrapolation of saturable uptake by cryopreserved human hepatocytes predicts clearance comparable with the observed hepatic clearance although fluvastatin and ro- suvastatin required a scaling factor of 11 and 6.9, respectively. This study suggests that in vitro uptake assays using human kidney slices and hepatocytes provide a good prediction of the overall tubular secretion and hepatic clearances of anionic drugs and renal drug-drug interactions. It is also recommended that in vitro-in vivo extrapolation be performed in animals to obtain more reliable prediction. Introduction Prediction of the pharmacokinetic properties of drugs in humans in the preclinical stages of drug development is very important to avoid failure in the subsequent clinical stages because of poor pharmacoki- netic properties. The liver and kidney are the major systemic clearance organs for drugs in the body. Drug-metabolizing enzymes and trans- porters play significant roles in the renal and hepatic elimination of drugs from the systemic circulation, and, therefore, these activities are a critical factor determining systemic drug exposure. It is well ac- cepted that, because of large species differences in drug metabolism, the metabolic clearance determined in animal studies cannot always be directly extrapolated to humans. In vitro systems, such as liver microsomes and hepatocytes, have been developed to replace animal studies and provide reliable predictions of the hepatic metabolic clearance of drugs (Obach, 1999; Stringer et al., 2008; Chiba et al., 2009; Kilford et al., 2009). Animal scale-up has been widely used to predict the renal clearance of drugs in humans (Adolph, 1949; Boxenbaum, 1982). Renal elim- ination occurs in the glomeruli and proximal tubules where filtration and secretion occur, respectively. Animal scale-up is undoubtedly useful for drugs that are eliminated in the urine by glomerular filtra- tion because the glomerular filtration rate depends on the molecular size and conforms to allometric scaling across species. However, Mahmood (1998) reported outliers for this prediction. These may occur because of species difference in the tubular secretion of drugs mediated by renal transporters. We reported a species difference in the This study was supported in part by a Grant-in-Aid for Scientific Research (A) [Grant 20249008] (to Y.S.); and Mandom International Research Grants for Alter- natives to Animal Experiments (to H.K.). Article, publication date, and citation information can be found at http://dmd.aspetjournals.org. doi:10.1124/dmd.110.036129. □ S The online version of this article (available at http://dmd.aspetjournals.org) contains supplemental material. ABBREVIATIONS: OAT, organic anion transporter; DDI, drug-drug interaction; PAH, p-aminohippurate; LC, liquid chromatography; MS, mass spectrometry; IVIVE, in vitro-in vivo extrapolation. 0090-9556/11/3906-1031–1038$25.00 DRUG METABOLISM AND DISPOSITION Vol. 39, No. 6 Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics 36129/3688348 DMD 39:1031–1038, 2011 Printed in U.S.A. 1031 http://dmd.aspetjournals.org/content/suppl/2011/03/07/dmd.110.036129.DC1 Supplemental material to this article can be found at: at ASPET Journals on August 17, 2017 dmd.aspetjournals.org Downloaded from