ABSTRACT

In its role as a barrier the skin participates in homeostasis by limiting (a) water loss (1,2) and (b) percutaneous absorption of environmental agents (3,4).

The stratum corneum’s role as a double barrier is intimately linked by its degree of hydration (5,6), transport mechanisms being diffusional (3,7). In humans (8,9) and in animals (10), an increase in water permeability of the skin corresponds to an increase in permeability to topically applied compounds. However, most of the studies dealing with this topic are only quantitative observations, and the relationship linking these two factors is unknown.