The metabolism of muzolimine

The metabolism of muzolimine, 3-amino-1-(3,4-dichloro-alpha-methyl-benzyl)-2-pyrazoline-5-one has been studied both in vivo and in vitro in various animal species. Using unlabelled muzolimine the major urinary metabolite in all species studied has been shown by chromatography and mass-spectrometry to have properties identical to synthetic N'-(1-aminoethylidene)-3,4-dichloro-acetophenone hydrazone. In addition, 3,4-dichloroacetophenone, 3,4-dichloromandelic and 3,4-dichlorobenzoic acids have been detected and quantified using GLC techniques. In vitro experiments using hepatic microsomal preparations from various species show that cleavage across the C-N1 bond occurs yielding 3,4-dichloroacetophenone and 3-amino-2-pyrazoline-5-one. The hydrazone was the major metabolite produced by these systems. Moreover, this compound also appears as the major metabolite in faecal extracts. Reverse-Phase High-Performance Liquid Chromatographic techniques have been employed for analysis of in vitro metabolism of muzolimine and confirmed the formation of the above metabolites.