PT  - JOURNAL ARTICLE
AU  - Iain J. Martin
AU  - Richard J. Lewis
AU  - Michael A. Bernstein
AU  - Iain G. Beattie
AU  - Craig A. Martin
AU  - Robert J. Riley
AU  - Brian Springthorpe
TI  - Which Hydroxy? Evidence for Species Differences in the Regioselectivity of Glucuronidation in Rat, Dog, and Human in Vitro Systems and Dog in Vivo
AID  - 10.1124/dmd.106.009282
DP  - 2006 Sep 01
TA  - Drug Metabolism and Disposition
PG  - 1502--1507
VI  - 34
IP  - 9
4099  - http://dmd.aspetjournals.org/content/34/9/1502.short
4100  - http://dmd.aspetjournals.org/content/34/9/1502.full
SO  - Drug Metab Dispos2006 Sep 01; 34
AB  - The glucuronidation of (1S,2R,3R,5R)-3-(hydroxymethyl)-5-[7-{[(1R,2S)-2-phenylcyclopropyl]amino}-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]cyclopentane-1,2-diol (AZ11939714) was studied in UDP-glucuronic acid (UDPGA)-supplemented hepatic microsomes from rat, dog, and human liver. The major biliary metabolite of this compound after intraduodenal administration to a beagle dog was also studied. The techniques of HPLC, HPLC-MS and HPLC-NMR were used to characterize the glucuronides. An analysis of the proton NMR chemical shift differences between parent and metabolites was sufficient to deduce the sites of glucuronidation, although these were confirmed by 2D ROESY experiments. In dog microsomes, AZ11939714 was O-glucuronidated exclusively at the 1-position of the cyclopentanediol. This glucuronide was also the major metabolite in dog bile. In human microsomes, AZ11939714 was O-glucuronidated almost exclusively at the 3-hydroxymethyl position. Rat microsomes produced a mixture of glucuronides at the 2-position of the cyclopentanediol (major) and at the 3-hydroxymethyl position (minor). A clear qualitative species difference in the glucuronidation of AZ11939714 has been demonstrated in vitro. This may have implications for the choice of laboratory species to study the pharmacokinetics and safety of this compound. The American Society for Pharmacology and Experimental Therapeutics