Stereoselective Permeation of Tretinoin and Isotretinoin through Enhancer-Treated Rat Skin. I. Effect of Ethanol and Sodium Dodecyl Sulfate

Many properties of chemicals depend on their streochemistry. Among these, the effects of streoisomerism on percutaneous absorption of drugs, which is subject of the present investigation, is not well studied yet. In this study, tretinoin (TT) and isotretinoin (ITT) (geometric isomers) were chosen and their permeations (alone or in the presence of each other) through enhancer-treated excised rat skin were studied. These studies employed static diffusion cells, saturated solution of drugs in water:propylene glycol system as the donor phase and aqueous solution of Tween20 as the receptor phase. Aqueous solutions of sodium dodecyl sulfate (SDS) (2, 4, 6 and 8%, w/v) and ethanol (EtOH) (25, 50, 75 and 96%, v/v) were used as enhancers. Results showed that TT permeates SDS-treated skin by about 1.6-1.8 times faster than ITT (P