Identification of basic metabolites of 4-[4-(p-chlo- robenzoyl)piperidino]-4'-fluorobutyrophenone, an experimental neuroleptic agent.

Two metabolites of 4-[4-(p-(chlorobenzoyl)piperidino]-4'-fluorobutyrophenone (RMI 9901) as well as unchanged drug, have been identified in the urine of rats following oral administration of the drug. Analysis of basic urine extracts by combined gas chromatography-mass spectrometry was employed for metabolite identification. N-dealkylation appears to be a major metabolic pathway and results in formation of 4-(p-chlorobenzoyl)piperidine (I). Subsequent oxidation of this metabolite results in the formation of 4-(p-chlorobenzoyl)-2-piperidone (II), and represents rather unusual metabolic pathway for compounds of this chemical class.