title: Two-layer membrane model for iontophoretic drug transport through excised rat skin.
abstract: Iontophoretic and passive transport of an ionized drug (sulfisoxazole) across excised rat skin was studied using a two-chamber cell with four electrodes under successive experimental conditions: without electrical current (stage-I) and with electrical current (stage-II). Two iontophoretic/diffusion models, i.e. a one-layer membrane model and a two-layer membrane model, in which a difference in the electrical potential gradient was taken into account between the stratum corneum and epidermis/dermis layer, were constructed to describe the non-steady-state drug permeation process during ionotrophoresis. The observed iontophoretic lag-time was two times greater than the calculated value based on the one-layer membrane model. According to the two-layer membrane model, the calculated ionotophoretic lag-time agreed with the observed value. It was revealed by model adaptation to the observed data that the stratum corneum fraction of the electro-chemical potential difference across the whole skin caused by the iontophoresis was around 90%. This result was consistent with the observation that the direct current resistance of whole skin was seven times greater than that of stripped skin.
authors.affiliation: Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Inada
authors.forename: K
authors.initials: K
authors.lastname: Mizuguchi
authors.forename: K
authors.initials: K
authors.lastname: Katayama
authors.forename: M
authors.initials: M
authors.lastname: Kakemi
authors.forename: T
authors.initials: T
authors.lastname: Koizumi
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004058:Diffusion; D066298:In Vitro Techniques; D007478:Iontophoresis; D008297:Male; D008567:Membranes, Artificial; D008954:Models, Biological; D051381:Rats; D017208:Rats, Wistar; D012869:Skin Absorption; D013444:Sulfisoxazole / Q000008:administration & dosage / Q000493:pharmacokinetics
chemical_list: D008567:Membranes, Artificial; D013444:Sulfisoxazole