Structure-Metabolism Relationships in the Glucuronidation of d-Amino Acid Oxidase Inhibitors

Representative d-amino acid oxidase (DAAO) inhibitors were subjected to in vitro liver microsomal stability tests in the absence or presence of uridine diphosphate glucuronic acid (UDPGA). While carboxylate-based DAAO inhibitors displayed little glucuronidation, most DAAO inhibitors containing α-hydroxycarbonyl moiety exhibited nearly complete glucuronidation within 30 min. The one exception was 6-[2-(3,5-difluorophenyl)ethyl]-4-hydroxypyridazin-3(2H)-one 10, which exhibited some degree of resistance to glucuronidation by liver microsomes from mice, rats, and humans.