Enhancement of percutaneous penetration of aniline and o-toluidine in vitro using skin barrier creams.

Aniline (ANI) and the human carcinogen o-toluidine (OT) are released at the workplace during the production and processing of rubber. Recently, we showed in rubber industry workers that a frequent use of skin barrier creams (SBC) increased the internal exposure of ANI and OT. In the present study, diffusion cells were used to investigate the effects of two SBC and one skin care cream (SCC) on percutaneous penetration of neat ANI and OT as well as of OT from a mixture with a workplace specific lubricant. The experiments were carried out with untreated and with skin creams treated human skin. A considerable percutaneous penetration enhancement of test compounds was observed for treated skin compared with untreated skin; the highest enhancement (mean factors 6.2-12.3) was found for SBC (based on oil in water emulsion) treated skin. The lowest penetration enhancement showed SCC treated skin (mean factors 4.2-9.7). The in vitro data support our findings in workers that the percutaneous absorption of aromatic amines significantly increases in presence of skin creams. The efficacy of skin creams to protect the percutaneous penetration of aromatic amines is not confirmed by our own experiments.