[Triperiden (Norakin): biotransformation in vivo and in vitro]

After oral application of triperiden (1; Norakin) to male Wistar rats besides the unchanged isomers of 1 (1a and 1b, respectively [3]) six hydroxy metabolites and an artifact were isolated from urine and also identified in faeces. All metabolites are hydroxy derivatives of the piperidine and the tricyclic moieties of the molecule 1a. No hydroxylation of the phenyl ring was observed. 10-20% of the metabolites were sulfate and/or glucuronide conjugates. Main metabolites were 2 and 3 (greater than 50% of the total excretion products). About 70% of 1a, 1b and metabolites were excreted with the urine. The in vivo metabolites also could be identified in the 9000 g supernatant of rat and human liver homogenates.