PURPOSE: The in vivo hepatic extraction ratio of cynomolgus monkeys was correlated with the corresponding in vitro extraction ratios that were determined in monkey microsomal incubations. METHOD: For compounds that are eliminated mainly through liver phase I metabolism, the extraction ratio calculated from liver microsomal stability studies should correlate with their in vivo hepatic extraction ratios and also with their oral bioavailability in monkey. We used both well-stirred and parallel tube models of intrinsic clearance for the correlation. We also calculated extraction ratios for compounds within a given therapeutic area from fraction absorbed values that were estimated from the Caco-2 absorption model. RESULT: The present data show that in vitro extraction ratios in monkey microsomes are predictive of the in vivo hepatic extraction ratios in monkeys. All compounds with high extraction ratio (>70%) in vivo were successfully classified as high-extraction-ratio compounds based on the in vitro monkey microsomal stability data. From the results of this study, it appears that the parallel tube model provided a slightly better classification than the well-stirred model. CONCULUSIONS: The present method appears to be a valuable tool to rapidly screen and prioritize compounds with respect to liver first-pass metabolism in monkeys at an early phase of drug discovery.
PURPOSE: The in vivo hepatic extraction ratio of cynomolgus monkeys was correlated with the corresponding in vitro extraction ratios that were determined in monkey microsomal incubations. METHOD: For compounds that are eliminated mainly through liver phase I metabolism, the extraction ratio calculated from liver microsomal stability studies should correlate with their in vivo hepatic extraction ratios and also with their oral bioavailability in monkey. We used both well-stirred and parallel tube models of intrinsic clearance for the correlation. We also calculated extraction ratios for compounds within a given therapeutic area from fraction absorbed values that were estimated from the Caco-2 absorption model. RESULT: The present data show that in vitro extraction ratios in monkey microsomes are predictive of the in vivo hepatic extraction ratios in monkeys. All compounds with high extraction ratio (>70%) in vivo were successfully classified as high-extraction-ratio compounds based on the in vitro monkey microsomal stability data. From the results of this study, it appears that the parallel tube model provided a slightly better classification than the well-stirred model. CONCULUSIONS: The present method appears to be a valuable tool to rapidly screen and prioritize compounds with respect to liver first-pass metabolism in monkeys at an early phase of drug discovery.
Authors: R S Obach; J G Baxter; T E Liston; B M Silber; B C Jones; F MacIntyre; D J Rance; P Wastall Journal: J Pharmacol Exp Ther Date: 1997-10 Impact factor: 4.030
Authors: Joseph Cherian; Inhee Choi; Amit Nayyar; Ujjini H Manjunatha; Tathagata Mukherjee; Yong Sok Lee; Helena I Boshoff; Ramandeep Singh; Young Hwan Ha; Michael Goodwin; Suresh B Lakshminarayana; Pornwaratt Niyomrattanakit; Jan Jiricek; Sindhu Ravindran; Thomas Dick; Thomas H Keller; Veronique Dartois; Clifton E Barry Journal: J Med Chem Date: 2011-07-26 Impact factor: 7.446