TY - JOUR T1 - Prediction of the Intestinal First-Pass Metabolism of CYP3A Substrates in Humans Using Cynomolgus Monkeys JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 1967 LP - 1975 DO - 10.1124/dmd.110.034561 VL - 38 IS - 11 AU - Haruka Nishimuta AU - Kimihiko Sato AU - Yasuyuki Mizuki AU - Masashi Yabuki AU - Setsuko Komuro Y1 - 2010/11/01 UR - http://dmd.aspetjournals.org/content/38/11/1967.abstract N2 - To select high bioavailability compounds, it is necessary to predict the first-pass metabolism in the intestine. However, in vitro-in vivo predictions of the intestinal metabolism have proven both challenging and less definitive. The purpose of this study was to investigate prediction of intestinal first-pass metabolism in humans using cynomolgus monkeys. First, we investigated intrinsic metabolic activities in intestinal microsomes of monkeys (MIM) and humans (HIM) (CLint, MIM and CLint, HIM, respectively) of 18 CYP3A substrates. The CLint, MIM values were found to be relatively high and showed excellent correlation with the CLint, HIM values. Subsequently, we determined the plasma concentrations of 9 CYP3A substrates (buspirone, carbamazepine, diazepam, felodipine, midazolam, nicardipine, nifedipine, saquinavir, and verapamil) in monkeys after an oral dose of 2 mg/kg with or without an oral dose of 5 mg/kg ketoconazole and calculated AUC(+vehicle)/AUC(+ketoconazole), defined as Fg, monkey(observed); we confirmed that the dose of ketoconazole inhibited only intestinal CYP3A metabolism by preliminary in vitro and in vivo experiments using ketoconazole. The Fg, monkey(observed) was lower than the Fg, human(observed) for most compounds, but moderate correlation was observed. Furthermore, using these data, we established a new methodology to estimate Fg, human(predicted) more precisely on the basis of the assumption that intestinal physiological conditions other than intrinsic metabolic activity would be the same between monkeys and humans. In conclusion, the in vivo model using cynomolgus monkeys in this study is useful for prediction of intestinal first-pass metabolism by CYP3A in humans because it was able to predict Fg, human of all nine compounds investigated. ER -