Which hydroxy? Evidence for species differences in the regioselectivity of glucuronidation in rat, dog, and human in vitro systems and dog in vivo.
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.
Martin
Iain J
IJ
Department of Physical and Metabolic Science, AstraZeneca R&D Charnwood, Bakewell Road, Loughborough, LE11 5RH, UK.
Lewis
Richard J
RJ
Bernstein
Michael A
MA
Beattie
Iain G
IG
Martin
Craig A
CA
Riley
Robert J
RJ
Springthorpe
Brian
B
D000818:Animals; D001646:Bile / Q000378:metabolism; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D003198:Computer Simulation; D004285:Dogs; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005343:Fibrinolytic Agents / Q000737:chemistry / Q000493:pharmacokinetics*; D020719:Glucuronides / Q000737:chemistry / Q000378:metabolism*; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry; D008862:Microsomes, Liver; D008954:Models, Biological; D015394:Molecular Structure; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D013045:Species Specificity
D005343:Fibrinolytic Agents; D020719:Glucuronides