Two-layer membrane model for iontophoretic drug transport through excised rat skin.
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.
Inada
H
H
Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Mizuguchi
K
K
Katayama
K
K
Kakemi
M
M
Koizumi
T
T
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
D008567:Membranes, Artificial; D013444:Sulfisoxazole