Skin permeation model of phenyl alcohols: comparison of experimental conditions

Abstract

This study was conducted primarily to establish the significance of the experimental conditions in the determination of permeability coefficients. In order to do this, standard in vitro skin permeation methods were used to determine the permeability coefficient ( k p) of a homologous series of phenyl alcohols, with a wide range of lipophilicity, by two different experimental conditions through rat skin; first, using solutions (at 75% saturation concentration) of the penetrants in the donor compartment and second using saturated solutions added with an excess of the penetrant. The k p values obtained by these techniques were compared. Solubility of the phenyl alcohols in the donor phase and partition coefficients in n-octanol/water systems were also assessed, and the correlations between the permeability coefficients and these parameters were established. A bilinear relationship between the permeability coefficients of the penetrants and the corresponding lipophilicity index was found. The skin penetration model of phenyl alcohols was compared with another homologous series ( p-alkylanilines) and the optimal lipophilicity value in terms of log P ( n-octanol) was found to be 3.1 in both cases.