ABSTRACT
The area of percutaneous absorption has been established as a significant part
of dermatotoxicology. Human health risk assessment includes an estimate for
percutaneous absorption where dermal exposure is involved. Some estimate of
percent dose absorbed or steady-state absorption (flux) is included. Behind these
generated numbers lies the question of validation. Human exposure is a risk
endpoint, and if a model is used, that model should be validated for humans in
vivo. Second, there is the question of relevance of the particular risk assessment
situation to the provided percutaneous absorption data. For example, is an
absorption estimate derived over a long period of exposure applicable to a short
exposure period? (There are some examples where this is not the case.) Also,
multiple exposures (daily or weekly) can exceed single exposure estimates in
some situations. Third, some limitations (lag time, lipophilicity) to the in vitro
diffusion model are shown. Finally, the data showing skin delivery and
percutaneous absorption of chemicals from clothing fabric are discussed. The
overall interest is relevant and validates percutaneous absorption data and
proper data interpretation.
