Sunscreens' photochemical behaviour: in vivo evaluation by the stripping method

• Published in: International journal of cosmetic science Vol. 19; no. 2; pp. 87 - 101
• Main Authors: MARGINEAN LAZAR, G., FRUCTUS, A.E., BAILLET, A., BOCQUET, J.L., THOMAS, P., MARTY, J.P.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Chapman and Hall 01.04.1997
• Subjects: emulsion type; photochemical behaviour; stripping method UV filters
• ISSN: 0142-5463; 1468-2494
• DOI: 10.1111/j.1467-2494.1997.tb00171.x

This study shows the influence of a water‐in‐oil emulsion and an oil‐in‐water emulsion on the photochemical behaviour of four sunscreen preparations containing various amounts of three UV filters: octyl methoxycinnamate, butyl methoxydibenzoylmethane, and 4‐methylbenzylidene camphor. With the stripping method in vivo, skin‐product interactions were evaluated after topical application and ultra‐violet exposure. Evaluations were also made under the same operating conditions as in determining sun protection factor in vivo. Results showed that each sunscreen preparation has a particular photochemical behaviour related to filter mixture and emulsion type. When developing a sunscreen preparation the choice of the emulsion type and filters is relevant for achieving optimum efficacy and spectral stability. Resume. L'objectif de cette etude a ete de montrer l'influence du type d'emulsion (eau dans huile ou huile dans eau a base de cristaux liquides) sur le comportement photochimique de quatre preparations solaires contenant differents taux de trois filtres: octyl methoxycinnamate, butyl methoxydibenzoylmethane et 4‐methylbenzyli‐dene camphor. Le methode du stripping, in vivo, permet d'evaluer les interactions peau‐produit apres application topique et irradiation. De plus, l'evaluation est faite dans des conditions operatoires identiques a celles preconisees pour la determination des indices de protection solaire. Les resultats qui ont ete obtenus montrent que chaque preparation solaire a son propre comportement photochimique directement lie au type d'emulsion et au melange des filtres. Au cours du developpement d'un produit solaire les choix du type d'emulsion et du melange des filtres ont une influence significative sur son efficacite et sa stabilite spectrale.