Abstract Cocaine N-demethylation by microsomal cytochrome P450s is the principal pathway in cocaine bioactivation and hepatotoxicity. P450 isozymes involved in N- demethylation of cocaine have not been elucidated yet and they differ from species to species. In humans and mice, P4503A contributes to cocaine N-demethylase activity, whereas in rats, both P4503A and P4502B participate. In the present study, contribution of ...