title: Prediction of the intestinal first-pass metabolism of CYP3A substrates in humans using cynomolgus monkeys.
abstract: 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) (CL(int, MIM) and CL(int, HIM), respectively) of 18 CYP3A substrates. The CL(int, MIM) values were found to be relatively high and showed excellent correlation with the CL(int, 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 F(g, 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 F(g, monkey(observed)) was lower than the F(g, human(observed)) for most compounds, but moderate correlation was observed. Furthermore, using these data, we established a new methodology to estimate F(g, 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 F(g, human) of all nine compounds investigated.
authors: Pharmacokinetics Research Laboratory, Dainippon Sumitomo Pharma Co, Ltd, Enoki 33-94, Suita, Osaka 564-0053, Japan. haruka-nishimuta@ds-pharma.co.jp
authors: Haruka
authors: H
authors: Nishimuta
authors: Kimihiko
authors: K
authors: Sato
authors: Yasuyuki
authors: Y
authors: Mizuki
authors: Masashi
authors: M
authors: Yabuki
authors: Setsuko
authors: S
authors: Komuro
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002853:Chromatography, Liquid; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism*; D065692:Cytochrome P-450 CYP3A Inhibitors; D006801:Humans; D007422:Intestines / Q000201:enzymology*; D007654:Ketoconazole / Q000494:pharmacology; D008099:Liver / Q000201:enzymology; D008252:Macaca fascicularis; D008297:Male; D008861:Microsomes / Q000201:enzymology*; D008862:Microsomes, Liver / Q000201:enzymology; D004364:Pharmaceutical Preparations / Q000008:administration & dosage / Q000097:blood*; D011237:Predictive Value of Tests; D013045:Species Specificity; D013379:Substrate Specificity; D053719:Tandem Mass Spectrometry
chemical_list: D065692:Cytochrome P-450 CYP3A Inhibitors; D004364:Pharmaceutical Preparations; D051544:Cytochrome P-450 CYP3A; D007654:Ketoconazole