RESUMO
Abstract The effectiveness of sun protection depends directly on the photo-protective product employed, the way it is used and the amount applied. Many studies report that sunscreens are often applied incorrectly, at amounts much lower than those recommended for the sun protection factor (SPF) specified on the label. When not used properly, the effectiveness of the product against sun exposure damage is reduced. Currently, sunscreens are available in a variety of different formulations and types, such as stick (bar), aerosol, cream, lotion, oil, tanning formulations and makeup. However, developing an effective stable photo-protective formula that can be correctly applied regardless of type poses a challenge, as effectiveness is dependent on several factors. Factors influencing effectiveness include sun exposure conditions (direct or indirect), level of protection (SPF), amount of product applied, maximum exposure period before reapplication, product type (spray, lotion, etc.), layer thickness required, coverage, and ability to spread and permeate into the skin. Studies comparing the effectiveness of different forms of sunscreens, the amount of product applied by consumers and SPF and UVA protection determined by validated methodologies, are lacking. Therefore, the objective of this study was to review the available literature on the topic and discuss the effectiveness of sunscreen formulations and factors influencing sun protection. This review was carried out on the scientific databases MEDLINE, PubMed and Scielo. Of the many publications retrieved, thirty-nine articles most relevant for this review were selected.
RESUMO
Objective To investigate the use situation of sunscreen agent in the sunblock cosmetics.Methods Statistic analysis was performed in the kinds,frequencies,dosages of sunsereen agents and the mark dosage coincidence in 414 cosmetics from Sep.2004 to Aug.2007.Results Fourteen kinds of sunscreen agents including phenylbenzimidazole sulphonic acid and its potassium,sodium and triethanolamine salts,benzophenone-4,benzophenone-5,benzophenone-3,isopentyl p-methoxycirmamate, 4-methylbenzylidene camphor,ethylhexyl dimethyl PABA,butyl methoxydibenzoylmethane,octocrylene,ethylhexyl methoxycinnamate,ethylhexyl salicylate,ethylhexyl triazone,methylene bis-benzotriazolyl tetramethylbutylphenol,bis- ethylhexyloxyphenol methoxyphenyl triazine were detected in 414 cosmetics.The use frequency of ethylhexyl methoxycinnamate was above 90%,butyl methoxydibenzoylmethane was 30%,benzophenone-3 and ethylhexyl salicylate were 15% and 11% respectively,and others were less than 10%.The rate of exceed standard limit of ethylhexyl methoxycinnamate,octocrylene, ethylhexyl salicylate,4-methylbenzylidene camphor ethylhexyl dimethyl PABA were 0.24%,0.97%,1.21%,0.48% and 0.24% respectively.The mark dosage coincidence rate of 14 kinds of sunscreen agents were from 42.9% to 89.5%.Conclusion The many kinds of sunscreen agents were used in the sunblock cosmetics,so the special attention should be paid to the cosmetics safety.