Penetration of industrial chemicals across the skin: a predictive model.

The recently reported dermal absorption and toxicity potential of industrial chemicals is reconsidered using an alternative physicochemically based model of skin penetration. In this model, the outermost, and least permeable, component of the skin [namely, the stratum corneum (SC)] is considered to provide only a lipoidal transport pathway into the body for chemicals that come into contact with the skin. The predictive algorithm of the model is biophysically compatible with known SC properties, and is based on experimental determinations of permeability coefficients through human skin in vitro for nearly 100 compounds of widely divergent physicochemical properties. This simpler prediction results in significantly lower estimates of maximum percutaneous penetration fluxes.