Studies on the demethylation,hydroxylation and N-oxidation of imipramine in rat liver

Metabolic pathways responsible for the demethylation, N -oxidation and 2-hydroxylation of imipramine were studied in rat liver in vitro . Isotope-trapping experiments have revealed that imipramine- N -oxide is not involved as an intermediate in the formation of desmethylimipramine from imipramine. The enzyme systems for demethylation and 2-hydroxylation are induced by phenobarbital, but that for N -oxidation is not induced. All available evidence indicates that the demethylation, N -oxidation and 2-hydroxylation reactions may be independent of one another.