Absorption through the skin: theory, in vitro techniques and their applications.
Human exposure to chemicals often occurs by skin contact and estimations of percutaneous absorption play an important part in the assessment of the risks involved. It is well established that the rate determinant step in absorption through skin is diffusion across the outermost layer, the stratum corneum, a process that is known to be passive in character. This latter property, combined with the stability of the stratum corneum, makes possible meaningful in vitro measurements of skin permeability in diffusion cells. The use of diffusion cells has permitted the development of a thorough understanding of the physical chemistry of the absorption process. Various parameters can be established in vitro that allow assessments of absorption to be calculated for a range of exposure situations. Another major advantage is that human skin samples may be used in vitro and, since no animal model has been found to be adequate for all penetrant chemicals, this has proved to be the most relevant tissue for assessing absorption in practical circumstances.
D004058:Diffusion; D004817:Epidermis / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D010539:Permeability; D012869:Skin Absorption