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

• Published in: International journal of cosmetic science 2011-08, Vol.33 (4), p.359-365
• Main Authors: Balogh, T. S., Pedriali, C. A., Gama, R. M., de Oliveira Pinto, C. A. S., Bedin, V., Villa, R. T., Kaneko, T. M., Consiglieri, V. O., Velasco, M. V. R., Baby, A. R.
• Format: Article
• Language: English
• Subjects: Animal models; Animals; Applied sciences; artificial tanning; Carbon; Chemical industry and chemicals; Coloration; Cosmetics; Cosmetics, toiletries; Dihydroxyacetone; Exact sciences and technology; Gels; melanin; Membranes, Artificial; Mexameter® MX 18; Models, Theoretical; moulted snake skin; Pigmentation; Pigments; Self; Skin cancer; Snakes; Stratum corneum; Sugar; Sunbathing; Tanning; Tyrosine; U.V. radiation; Washing products. Cosmetics and toiletries. Perfumes
• ISSN: 0142-5463; 1468-2494
• DOI: 10.1111/j.1468-2494.2011.00638.x

Synopsis 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 formulasis 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 T0 (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. Résumé Des formules de produits autobronzant sont devenues ces dernières années de plus en plus populaires par leur capacitéà permettre de donner aux personnes un bronzage certain sans les risques d’un cancer cutané. La plupart des autobronzants actuellement sur le marché contiennent de la dihydroxyacetone (DHA), un sucre cétonique avec trois carbones. La pigmentation provisoire obtenue avec ces formules est conçue pour ressembler à un bronzage UV‐induit. Cette étude a évalué par mesure au Mexameter®MX 18, l’efficacité de gels de carbomer et de bases émulsionnées à froid s sur la pigmentation cutanée, en utilisant différentes concentrations d’un système composé d