Methods for in Vitro Skin Metabolism Studies

It now has been widely established that the skin is capable of a variety of biotrans-formational processes (Pannatier et al., 1978; Bickers, 1980; Kappus, 1989). Although the activities of many enzymatic processes, particularly oxidative ones, are much lower in the skin than in the liver (Bronaugh et al., 1989), reductive processes and N-acetyltransferase have been reported to be relatively active in skin (Kawakubo et al., 1988; Fuchs et al., 1989). The importance of metabolism during percutaneous absorption depends on the structure and biological activity of the penetrating compounds and metabolite(s). For benzo[a]pyrene, metabolism in the skin is necessary for its activation to a proximate skin carcinogen.