Skin absorption and human risk assessment.

A common practice is to assume that percutaneous absorption does not significantly contribute to total bioavailability and therefore, absorption through other routes is more important to human risk assessment. The skin can represent a significant barrier to absorption, but some substances are absorbed to a significant extent. Since there is a potential for percutaneous penetration that is not consistent between species or substances, the assessment of the potential contribution of total body burden from dermal exposures should be considered. This review briefly discusses some theories, practices, and factors that affect percutaneous absorption with an emphasis on how percutaneous absorption evaluations apply to human risk assessment.