Study of sunless tanning formulas using molted snake skin as an alternative membrane model.

Sunless tanning formulas have become increasingly popular in recent years for their ability to give people convincing tans without the dangers of skin cancer. Most sunless tanners currently on the market contain dihydroxyacetone (DHA), a keto sugar with three carbons. The temporary pigment provided by these formulas is designed to resemble a UV-induced tan. This study evaluated the effectiveness of carbomer gels and cold process self emulsifying bases on skin pigmentation, using different concentrations of a chemical system composed of DHA and N-acetyl tyrosine, which are found in moulted snake skins and their effectiveness was tested by Mexameter(®) MX 18. Eight different sunless tanning formulas were developed, four of which were gels and four of which were emulsions (base, base plus 4.0%, 5.0% and 6.0% (w/w) of a system of DHA and N-acetyl tyrosine). Tests to determine the extent of artificial tanning were done by applying 30 mg cm(-2) of each formula onto standard sizes of moulted snake skin (2.0 cm × 3.0 cm). A Mexameter(®) MX 18 was used to evaluate the extent of coloration in the moulted snake skin at T(0) (before the application) and after 24, 48, 72, 168, 192 and 216 h. The moulted snake skins can be used as an alternative membrane model for in vitro sunless tanning efficacy tests due to their similarity to the human stratum corneum. The DHA concentration was found to influence the initiation of the pigmentation in both sunless tanning systems (emulsion and gel) as well as the time required to increases by a given amount on the tanning index. In the emulsion system, the DHA concentration also influenced the final value on the tanning index. The type of system (emulsion or gel) has no influence on the final value in the tanning index after 216 h for samples with the same DHA concentration.

Novas metodologias analíticas para avaliação da eficácia fotoprotetora (in vitro) - revisão / New analytical methods for photoprotection effectiveness testing (in vitro) - a review

Atualmente, são utilizadas técnicas in vitro e in vivo para a avaliação do Fator de Proteção Solar (FPS) e do Fator de Proteção de UVA (FPA). O presente trabalho propõe a revisão das técnicas para as avaliações desses fatores in vitro preconizadas por FDA (Food and Drug Administration Agency) e COLIPA (European Cosmetic, Toiletry and Perfumery Association). O enfoque maior foi direcionado à análise espectrofotométrica de soluções diluídas e à espectrofotometria de reflectância com esfera integrada.

Currently, both in vitro and in vivo techniques are used to measure Sun Protection Factor (SPF) and UVA Protection Factor (APF). This paper reviews the in vitro techniques to test these factors, recommended by the FDA (USA Food and Drug Administration) and COLIPA (European Cosmetic, Toiletry and Perfumery Association). The main focus is on the spectrophotometric analysis of dilute solutions and the use of reflectance spectrophotometry with an integrating sphere.