MOLECULAR STRUCTURE AND DIFFUSIONAL PROCESSES ACROSS INTACT EPIDERMIS
Abstract
The penetration rate for small molecular weight alcohols is approximately given by the expression: Js = Kp Km dCs, where Kp = 0.001-3 cm/ hr. is essentially the permeability constant for water in the membrane, Km is the membrane-water partition coefficient for the alcohol and dCs is the concentration difference across the membrane. The activation energy for the penetration water and the polar alcohols, through hydrated stratum corneum is approximately 15 Kcal/mole. Extensive immersion in water effects the 'barrier' function of stratum corneum only slightly; principally by opening 'pores' which contribute to the diffusion a parallel flux which is relatively small above room temperature. Penetration through the stratum corneum is not primarily intercellular or appendageal. The hydrated stratum corneum seems to be best described as a dense, effectively homogeneous phase into which small molecular weight polar non-electrolytes dissolve with strong chemical interaction and through which diffusion occurs remarkably slowly.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1965
- Accession Number
- AD0621078
Entities
People
- Robert J. Scheuplein
Organizations
- Harvard Medical School