Metabolism of a novel CCK-B antagonist in rat, dog and human liver microsomes.

1. The in vitro metabolism of a novel CCK-B antagonist ((+)-N-[1-adamantane-1-methyl)-2,4-dioxo-5-phenyl-2,3,4,5-tetrahydro-1H- 1, 5-benzodiazepin-3-yl]N'-phenyl-urea; GV150013X) was investigated using rat, dog and human liver microsomes. 2. Four monohydroxy and four dihydroxy metabolites of GV150013X in rat and man were identified by comparison with authentic standards using HPLC and mass spectrometry. 3. The dihydroxy metabolite M1 was not detected in dog liver microsomes mixtures. 4. The formation of dihydroxylated metabolites proceeds via monohydroxylated metabolites M5 and M8 and not directly from GV150013X. 5. A monohydroxy metabolite M5 was the major metabolite in rat and dog, with M5 and dihydroxy metabolites M2 and M3 major metabolites in man.