VITAMIN-E AS A HUMAN SKIN PENETRATION ENHANCER

Vitamin E (alpha-tocopherol) has demonstrated effectiveness as a human skin penetration enhancer by increasing the permeability coefficient of radiolabeled hydrocortisone approximately two-fold in excised cadav er skin. Skin permeability experiments were carried out in Franz (vert ical) diffusion cells in infinite dose experiments. In all five of the se experiments, positive enhancement of permeability versus untreated controls was observed (p = 0.014 showing enhancement factor greater th an 1). Furthermore, a reduction in lag time was observed with Vitamin E treated skin. It is postulated that Vitamin E acts as a penetration enhancer by intercalating within the lipid bilayer region of the strat um corneum, thus altering the characteristics of the membrane affectin g permeability, presumably by disordering gel phase lipids. Unlike oth er well known enhancers, Vitamin E is generally thought to be non-irri tating, and additionally, possesses antioxidant and emollient properti es.