Effects of two barrier creams on the diffusion of benzo[a]pyrene across human skin

Barrier hand creams, often containing antiseptic agents, may provide a form of protection not only for health care professionals, but also for workers in the chemical and pharmaceutical industries. To evaluate the efficacy of two such barrier creams available on the South African market, the in vitro diffusion of a model compound, benzo[a]pyrene, through human skin at 20 degrees and 37 degrees C was studied. Treated (10 min) and untreated human skin disks (4 mm in diameter) were mounted in flow cells of a continuous flow-through diffusion apparatus. Buffer/tritiated benzo[a]pyrene was collected from the acceptor chambers at 2-hour intervals for a total of 24 hours and counted in a liquid scintillation counter. At 20 degrees C no significant differences could be detected between the flux rates of benzo[a]pyrene across barrier cream treated and untreated skin. However, at 37 degrees C Skinguard significantly increased flux rates of this carcinogen. Skin barrier creams therefore need to be carefully scrutinised with respect to their protective effects because the latter may vary for molecules with different chemical properties.