PT - JOURNAL ARTICLE AU - Benjamin M. Johnson AU - Amrita V. Kamath AU - John E. Leet AU - Xiaohong Liu AU - Rajeev S. Bhide AU - Ravindra W. Tejwani AU - Yueping Zhang AU - Ligang Qian AU - Donna D. Wei AU - Louis J. Lombardo AU - Yue-Zhong Shu TI - Metabolism of 5-Isopropyl-6-(5-methyl-1,3,4-oxadiazol-2-yl)-<em>N</em>-(2-methyl-1<em>H</em>-pyrrolo[2,3-<em>b</em>]pyridin-5-yl)pyrrolo[2,1-<em>f</em>][1,2,4]triazin-4-amine (BMS-645737): Identification of an Unusual <em>N</em>-Acetylglucosamine Conjugate in the Cynomolgus Monkey AID - 10.1124/dmd.108.022624 DP - 2008 Dec 01 TA - Drug Metabolism and Disposition PG - 2475--2483 VI - 36 IP - 12 4099 - http://dmd.aspetjournals.org/content/36/12/2475.short 4100 - http://dmd.aspetjournals.org/content/36/12/2475.full SO - Drug Metab Dispos2008 Dec 01; 36 AB - 5-Isopropyl-6-(5-methyl-1,3,4-oxadiazol-2-yl)-N-(2-methyl-1H-pyrrolo[2,3-b]pyridin-5-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amine (BMS-645737) is a potent and selective vascular endothelial growth factor receptor-2 antagonist. In this study, liquid chromatography/tandem mass spectrometry and NMR were used to investigate the biotransformation of BMS-645737 in vitro and in the cynomolgus monkey, dog, mouse, and rat. Metabolic pathways for BMS-645737 included multistep processes involving both oxidation and conjugation reactions. For example, the 2-methyl-1H-pyrrolo moiety underwent cytochrome P450-catalyzed hydroxylation followed by oxidation to a carboxylic acid and then conjugation with taurine. Alternatively, the 5-methyl-1,3,4-oxadiazol-2-yl moiety was metabolized by hydroxylation and then conjugation with sulfate. The pyridin-5-yl group underwent direct glucuronidation in hepatocytes (dog, monkey, human) and conjugation with N-acetylglucosamine in the monkey. Conjugation with glutathione and processing along the mercapturic acid pathway was a minor metabolic pathway in vivo, although BMS-645737 did not form conjugates in the presence of glutathione-supplemented liver microsomes. Other minor biotransformation pathways included oxidative dehydrogenation, dihydroxylation, and hydrolytic opening of the oxadiazole ring followed by either deacetylation or hydrolysis of the resulting diacyl hydrazide. Whereas previous studies have shown the formation of N-acetylglucosamine conjugates of alcohols, arylamines, and other small molecules, this report describes the biotransformation of a heterocyclic aromatic amine via direct conjugation with N-acetylglucosamine. The American Society for Pharmacology and Experimental Therapeutics