The requirements of an effective sunscreen include high solubility of organic filters in the vehicles, efficient dispersion of physical filters, absence of crystallization afte rapplication onto the skin surface and lack of aggregation phenomena of micronized powders in the product. Moreover, an effective sunscreen requires an appropriate load of inorganic filters as well as their optimum wetting and the formulation of the transparent limit layer (i.e. the residual layer on the skin that cannot be further thinned by massage) over the skin surface.
Excerpt Only This is a shortened version or summary of the article that appeared in the Feb. 01, 2002 issue of Cosmetics & Toiletries magazine. The full content is not currently available online.