Dermal penetration and systemic distribution of 14C-labeled vitamin E in human skin grafted athymic nude mice

In vivo percutaneous penetration and tissue distribution of 14C-labeled vitamin E applied to human skin grafted onto athymic nude mice were determined. At 1 hr, mouse skin contained the highest level of radioactivity, followed by the muscle, blood, liver, lung, adipose tissue, spleen, kidney, brain, heart, and eyes. A linear increase with time in tissue radioactivity was observed throughout the 24 hr experimental period. At 4 and 24 hrs skin grafts were highly radioactive. At 4 hrs the epidermis and the upper portion of the dermis contained more radioactivity than the remaining portion of the dermis. In contrast, at 24 hrs the highest level of radioactivity was detected in the lower dermis. No radioactivity was detected in expired air while 0.2% of the dose was found in the urine. The data show that vitamin E does penetrate skin and that the dermis acts as a barrier or reservoir for this highly lipophilic compound.