Study of the efficacy of 18 sun filters authorized in European Union tested in vitro.

In this work, the authors study the influence of filter concentration on the SPF in a topical product measured in vitro. Firstly, the method was adapted by determining that a mass of 15 mg of product must be applied on the PMMA (polymethylmethacrylate) plate in order to have the best correlation with results obtained in vivo. By using the highest concentration allowed by European legislation, the following ranking was drawn up in ascending order of efficacy: 3-Benzylidene camphor (1.66) < oxybenzone (3.01) < octylsalicylate (3.12) < PABA (3.36) < polysilicone 15 (3.64) < methylene bis-benzotriazolyl tetramethylbutylphenol (3.68) < PEG25 PABA (3.81) < benzophenone-4 (3.85) < 4-methylbenzylidene camphor (4.22) < homosalate (4.33) < octyltriazone (7.80) < phenylbenzimidazole sulfonic acid (8.31) < octyldimethyl PABA (8.71) < octocrylene (10.41) < octylmethoxycinnamate (10.42) < diethylhexylbutamidotriazone (12.58) <isoamylparamethoxycinnamate (15.14) < anisotriazine (20.0).