RT Journal Article
SR Electronic
T1 In Vitro Metabolism of Rivoglitazone, a Novel Peroxisome Proliferator-Activated Receptor γ Agonist, in Rat, Monkey, and Human Liver Microsomes and Freshly Isolated Hepatocytes
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 1311
OP 1319
DO 10.1124/dmd.111.038729
VO 39
IS 7
A1 Minoru Uchiyama
A1 Hiroko Koda
A1 Thomas Fischer
A1 Juergen Mueller
A1 Naotoshi Yamamura
A1 Minoru Oguchi
A1 Haruo Iwabuchi
A1 Osamu Okazaki
A1 Takashi Izumi
YR 2011
UL http://dmd.aspetjournals.org/content/39/7/1311.abstract
AB The in vitro metabolism of rivoglitazone, (RS)-5-{4-[(6-methoxy-1-methyl-1H-benzimidazol-2-yl)methoxy]benzyl}-1,3-thiazolidine-2,4-dione monohydrochloride, a novel thiazolidinedione (TZD) peroxisome proliferator-activated receptor γ selective agonist, was studied in liver microsomes and freshly isolated hepatocytes of rat, monkey, and human as well as cDNA-expressed human cytochrome P450 (P450) and UDP-glucuronosyltransferase (UGT) enzymes. Fourteen metabolites were detected, and these structures were elucidated by liquid chromatography-tandem mass spectrometry. Five initial metabolic pathways of rivoglitazone consisting of four oxidation pathways and one N-glucuronidation pathway were predicted in correspondence with those proposed for in vivo studies using rats and monkeys. In metabolization using liver microsomes, the TZD ring-opened mercapto amide (M22) and TZD ring-opened mercapto carboxylic acid (M23) were identified as the primary metabolite of the TZD ring-opening pathway and its sequential metabolite, which have not been detected previously from in vivo studies. Combination with S-adenosyl-l-methionine was useful to obtain the sequential S-methylated metabolites from the oxidative metabolites. N-Glucuronide and sequential TZD ring-opened metabolites were also found in liver microsomes in the presence of UDP-glucuronic acid. The O-demethyl-O-sulfate (M11), which is the major in vivo metabolite in rats and monkeys, was detected in all species of hepatocytes. In addition, a TZD ring-opened S-cysteine conjugate (M15) was detected in human hepatocytes. From these results, the in vivo metabolic pathways in humans were predicted to be the four oxidation and one N-glucuronidation pathways. The four oxidative metabolites were formed by multiple human P450 enzymes, and N-glucuronide was formed by UGT1A3 and UGT2B7.