Permeation of hairless mouse skin II: membrane sectioning techniques and influence on alkanol permeabilities

The barrier properties of hairless mouse skin were examined by separating the skin into its component epidermal and dermal strata, using both mechanical and thermal techniques, and then assessing the permeability of each stratum to the homologous alkanols. The permeability data, when compared to those obtained previously for full-thickness hairless mouse skin and to new data for the permeability of the alcohols through a perfect lipid membrane, allow assignment of diffusional resistances to the respective, anatomically distinguishable membrane strata. It was found that the principal barrier for the lower alkanols is the epidermis, which contains the stratum corneum. The effective aqueous tissue resistances of the cellular and aqueous strata of full skin, the epidermis, and the dermis were estimated using sectioned skins. This resistance was much greater than that of an equivalent thickness of water. These data and methods represent a novel approach in the permeation analysis of a biological tissue and offer a means of estimating the effects of skin damage on percutaneous absorption.