AIM: To identify the
metabolite of 3H 1,2 dihydro 2 (4 methyl phenylamino) methyl 1 pyrrolizinone(SFZ 47), a novel
anti inflammatory and analgesic agent in rabbits. METHODS: Urine samples from 0 to 12 h were collected after single oral dose of 100 mg SFZ 47 to each of four rabbits. The urine samples with or without hydrolysis by β glucuronidase/sulphatase were purified by SPE column (Sep Pak C 18 ) and analyzed with
LC/MS n for potential metabolites. RESULTS: Hydroxylated
metabolite of SFZ 47 and its conjugates of glucuronide and sulfate were first identified either by directly comparing the observed mass spectra and the chromatographic retention time with authentic substance or by the diagnostic ions in full scan MS n ( n =2,3) mode. CONCLUSION: According to the experimental results in this study, the major metabolic pathway of SFZ 47 in rabbits should be that the methyl group of SFZ 47 was oxidized to hydroxymethyl and then to carboxyl group, followed by conjugation with β glucuronic acid or sulfuric acid.