[Biotransformation of zipeprol (Mirsol) in humans. Gas chromatographic/mass spectrometric studies, using ammonia as a selective reactant gas (author's transl)].

After oral application of Zipeprol (Mirsol) the unchanged drug and nine degradation products were detected in human urine; six of them could be identified. All identified metabolites were detected in the alkaline urine fraction; after acid hydrolysis N-(2-hydroxyethyl)-piperazine was found as an artifact. With respect to the presented results, biotransformation of Zipeprol in man mainly follows three degradation routes: 1. alpha-cleavage leading to metabolite M4; 2. cleavage of the exocyclic N-C-bond of the piperazine ring leading to metabolites M3, M5, M6; 3. benzylic cleavage leading to benzylalcohol (M1); oxidation leading to 2-hydroxy-2-phenylacetic acid (mandelic acid, M2).