Effect of gramicidin on percutaneous permeation of a model drug

Abstract

This study investigated the enhancement effect of gramicidin, a cationic ionophore, on percutaneous absorption of a model drug, benzoic acid (BA), through rat abdominal skin. The mechanisms by which gramicidin increased skin permeability to BA were also investigated. Degree of hydration measured by the Karl Fisher method, the concentration gradient measured by cryostat analysis, and lipid concentration measured by the Fiske-Subbarow method were evaluated and compared. The results showed that BA permeation profiles through rat abdominal skin followed dose-and volume-dependent patterns. The pretreatment of gramicidin increased the permeation rate of BA through rat abdominal skin compared with the untreated control (18.89 vs. 10.86 µ g/cm 2 /hour). Change in skin permeation rate of BA after gramicidin pretreatment was closely correlated with the remaining skin water content. There were no significant differences in the amounts of phospholipid phosphorous between gramicidin pretreated and untreated skin. The enhancing effect of gramicidin on percutaneous absorption of a model drug is mainly attributed to increasing the diffusivity in the hydration domain of the skin and rearranging the lipid bilayer in the stratum corneum.

Topical emulsions containing ceramides: Effects on the skin barrier function and anti‐inflammatory properties

“…The skin permeability to exogenous compounds is affected by various factors, such as the degree of hydration and conformational changes in the biological membrane [25]. The enhancing effect of ceramides and cholesterol in percutaneous absorption of a model drug is mainly associated to an increase of the diffusivity in the hydration domain of the skin and a rearrangement of the lipid bilayer in the SC [26].…”