IN-VITRO STUDIES OF THE OXIDATIVE-METABOLISM OF L-737,415, A C5-CYCLOALKYLAMINE-1,4-BENZODIAZEPIN-2-ONE CCKB RECEPTOR ANTAGONIST

In an effort to investigate and characterise the metabolism of the C5- cycloalkylamine-1,4-benzodiazepin-2-one CCKB receptor antagonist L-737 ,415 a study was undertaken using rat liver microsomes. A procedure is described in which the metabolism of the unlabelled compound is first ly investigated analytically under a controlled set of conditions, the n scaled up to allow further metabolite elucidation. We also report th e use of HPLC with diode array detection, and thermospray LC-MS and LC -MS-MS, to detect and characterise the observed metabolites. From the UV spectra obtained with diode array detection and fragmentation analy sis fi om LC-MS-MS it is demonstrated that, contrary to other known be nzodiazepinones such as diazepam or the CCKB antagonist L-365,260, met abolism seems to occur predominantly at the C5 substituent. Further wo rk in which urine from rats dosed with L-737,415 was analysed indicate d that the in vitro microsomal assay provides a good model for in vivo metabolism for this class of compounds.