Isolation and identification of the N-oxide metabolite of picobenzide in human urine.

The possible presence of metabolites was investigated in the urine of 14 patients treated with N-(4-picolyl) 3,5 dimethyl benzamide (picobenzide) after an i.v. dose of 10 mg/Kg. The metabolites formed were isolated by liquid-liquid extraction processes and chromatographic techniques. The main metabolite of this neuroleptic agent is the N-oxide derivative, which appears in urine together with the unaltered drug. Identification of the metabolite was made by I.R. spectroscopy, nuclear magnetic resonance (NMR) and mass spectroscopy. Its structure was confirmed by comparison with the metabolite obtained by synthesis.