[The relationship between percutaneous rate of drug and its HPLC retention behavior]

A series of 13 p-aminobenzoate esters were selected as model drugs to study correlations between HPLC retention parameters and percutaneous rate. The octanol/water partition coefficient and solubility of these compounds were determined and their permeation through rat skin was measured using a Franz diffusion cell. Capacity factor and retention index were used as HPLC retention parameters and calculated from their retention times. The results indicate that for the p-aminobenzoate esters studied, the capacity factors and retention indices obtained in our experimental conditions are indicators of relative lipophilicity of drugs and can be used to predict their steady-state fluxes and permeation coefficients by using the Hansch equation. They are easy to obtain and reproducible enough to substitute for the more laborious and inaccurate partition coefficient values.