Absorption of 4,4'-methylenebis [2-chloroaniline] by human skin.

A system was developed to measure percutaneous absorption of water-insoluble environmental agents into human skin. Percutaneous absorption of 4,4'-[14C]methylenebis [2-chloroaniline] (MBOCA) was measured during dry contact exposure of MBOCA with organ cultures of neonatal foreskin. Time-dependent exposures, autoradiographs, and thin-layer chromatography indicated that MBOCA was rapidly and progressively absorbed and passed through the skin without being metabolized. The transepithelial penetration of MBOCA was temperature dependent. Under certain conditions, the stratum corneum contained more MBOCA than other layers in the skin, which suggested that the stratum corneum may not be the main barrier for percutaneous absorption of MBOCA. An assessment of risk confirmed that skin exposure is a cause for concern.