ABSTRACT
The percutaneous absorption of chemicals is most often studied using single chemicals applied to the surface of skin, often in a vehicle when solubilization is necessary. Exposure in most environmental and occupational scenarios occurs to combinations of chemicals. Similarly, most dermatological drugs are dosed in formulations composed of multiple additives. The difference is that in the pharmaceutical sector, components of a formulation are usually added for a specifi c purpose and their effects on drug absorption have been studied, or at least acknowledged. In environmental and occupational scenarios, the chemicals to which an individual is exposed are a function of their occurrence in the environment. The effect of one chemical, modulating absorption of a second mixture component, is not known. Risk assessments on topical exposure to chemical mixtures are presently an area of intense interest, but few quantitative approaches have been proposed.
