Possibilities and limitations of determining the water resistance of sunscreen products
Water resistance is another important test parameter for sunscreen products in addition to the sun protection factor and UV-A protection. Since the in vivo test method according to the Cosmetics Europe Standard appears to be too costly, especially in the early stages of development, a water resistance screening method without UV radiation is being presented and compared with other screening methods.
As a result of the practical investigations, a two-stage process for the screening of water resistance is recommended for sunscreen products. The results have been summarized in a publication which recently appeared in the International Journal of Cosmetic Science under the title “Chances and limits of an improved method to assess water resistance of cosmetic sunscreen products in vitro on polymethylmethacrylate plates”.