Levels of retinyl palmitate and retinol in the skin of SKH-1 mice topically treated with retinyl palmitate and concomitant exposure to simulated solar light for thirteen weeks

Retinyl esters account for more than 70% of the endogenous vitamin A found in human skin, and retinyl palmitate is one of the retinyl esters in this pool. Human skin is also exposed to retinyl palmitate exogenously through the topical application of cosmetic and skin care products that contain retinyl palmitate. To date, there is limited information on the penetration and distribution of retinyl palmitate and vitamin A within in the skin. In this study, the accumulation of retinyl palmitate and generation of retinol in the skin of male and female SKH-1 mice that received repeated topical applications of creams containing 0.0%, 0.1%, 0.5%, 1.0%, 5.0%, 10%, or 13% of retinyl palmitate 5 days a week for a period of 13 weeks were studied. Because products containing retinyl palmitate are frequently applied to sun-exposed skin, and because it is well established that exposure to sunlight and UV light can alter cutaneous levels of retinoids, mice in this study were additionally exposed 5 days a week to simulate...