PASSIVE TRANSPORT OF SMALL IONS THROUGH HUMAN STRATUM-CORNEUM

Some previous streaming potential and EMF measurements on human stratu m corneum in vitro (J. Control. Release 32 (1994) 249) are explained i n terms of a simple physical model based on the intercellular pathway for passive transport of small inorganic ions. These are assumed to di ffuse across the hydrophilic region of the lipid lamellae. The polar r egion is assumed to have a finite thickness and to be partly penetrabl e by ions from solution. The hypothesis that the Lipid ionized groups give rise to a point charge distribution together with a permanent dip ole distribution helps to explain the observed, apparent change in ski n selectivity with concentration.