Abstract:

The widespread use of sunscreen has caused great concern about its safety. Using sunscreen products can protect the skin from UV radiation, meanwhile, it may cause damage to the human body if it intervenes the circulatory system through the skin. In this study, the transdermal absorption of six sun-screening agents in full-thickness porcine ear skin was examined. The effects of skin condition, application dose, composition of receptor fluid, and retention of sun-screening agents at different skin depths were investigated. The results show that skin condition can affect the transdermal absorption of sun-screening agents, and the sun-screening agents can penetrate through frozen skin more easily. The penetration coefficient of each sun-screening agent was from 0.47 to 0.88. When the dosages were 0.5 mg and 2 mg, the transdermal absorption values of the sun-screening agents were different and increased with the increase of dosage, but the relationship was not linear. Adding different nonionic additives into the receptor fluid had little effect on the transdermal absorption of the sun-screening agents. The retention of the sun-screening agents in each layer of skin was related to their physical and chemical properties, such as molecular weight, water-oil balance coefficient, etc. Twenty-four hours after application, the transdermal absorption rate of BP-3 was 36.66%, higher than other sun-screening agents, and the margin of safety was 96.15. In general, the amounts of the sun-screening agents absorbed through the skin are relatively small and the health risks are low when the legally permitted dosages are used.

Key words: sun-screening agent, transdermal absorption, Franz diffusion cell, skin layer