ABSTRACT

There are numerous methods which have been employed to assess the

percutaneous absorption of toxic chemicals using both in vitro and in vivo animal

models. There is little debate that in vivo human studies are optimal for predicting

the absorption of topically applied chemicals in man. However, for highly toxic

or carcinogenic chemicals, ethics preclude conducting such studies when a risk

analysis is to be conducted. Similar considerations apply to the humane use of

animal surrogates. For chemicals which pose little direct adverse risk to man or

animals, experimental design and sampling limitations often apply to any

in vivo study. An important limitation is the inability to noninvasively sample

the venous drainage of a topical application site to determine the true cutaneous

flux for use as an input into systemic risk assessment models. Similarly, extensive

biopsies may not be taken to quantitate subtle, pre-clinical morphological or

biochemical manifestations of dermatotoxicity.