Skin permeability to aromatic carboxylic acids: an in vitro comparison in pig ear, white mouse and brown mouse

Synopsis A comparative study in vitro was undertaken for pig ear, white mouse, and brown mouse in which the percutaneous absorption of the following compounds, labelled with (14)C-carboxyl, were studied: benzoic acid, 2-methylbenzoic acid, and 4-methylbenzoic acid. The effects of temperature on the penetration through various skin membranes have been evaluated. The possible influences of chemical structure on transport across the skin were discussed. The results indicated that brown mouse skin was the most permeable membrane to all acids. Introduction of the methyl group to the aromatic ring, in the ortho and in the para positions, increased the diffusion coefficients for the benzoic acid.