title: Photostability evaluation of five UV-filters, trans-resveratrol and beta-carotene in sunscreens.
abstract: Trans-resveratrol (RES) is used in cosmetic formulations and beta-carotene (BTC) is a classical sunscreen antioxidant, but their photostability in sunscreens, a property directly correlated to performance and safety has not been addressed in the literature. This paper reports the assessment of RES and/or BTC influence on the photostability of five UV-filters (octyl methoxycinnamate - OMC, avobenzone -AVO, octocrylene - OCT, bemotrizinole - BMZ, octyltriazone - OTZ) in three different combinations after UVA exposure followed by the identification of degradation products and the assessment of photoreactivity. The evaluation of sunscreen photostability was performed by HPLC and spectrophotometric analysis, and degradation products were identified by GC-MS analysis. Components RES, BTC, OMC and AVO were significantly degraded after UV exposure (reduction of around 16% in recovery). According to HPLC analysis, all formulations presented similar photostability profiles. Eleven degradation products were identified in GC-MS analysis, among them products of RES, BTC, OMC and AVO photodegradation. All evaluated formulations were considered photoreactive, as well as the isolated compounds RES and AVO. Considering HPLC, spectrophotometric and GC-MS results, it is suggested that formulations containing BMZ were considered the most photostable. The combination RES+BTC in a sunscreen improved the photostability of AVO. The benefits of using a combination of antioxidants in sunscreens was demonstrated by showing that using RES+BTC+studied UV-filters led to more photostable formulations, which in turn implies in better safety and efficacy.
authors.affiliation: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Av. do Café s/n, Bairro Monte Alegre, Ribeirão Preto, SP, Brazil.
authors.forename: Juliana Vescovi
authors.initials: JV
authors.lastname: Freitas
authors.affiliation: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Av. do Café s/n, Bairro Monte Alegre, Ribeirão Preto, SP, Brazil.
authors.forename: Norberto Peporine
authors.initials: NP
authors.lastname: Lopes
authors.affiliation: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Av. do Café s/n, Bairro Monte Alegre, Ribeirão Preto, SP, Brazil. Electronic address: lorena@fcfrp.usp.br.
authors.forename: Lorena Rigo
authors.initials: LR
authors.lastname: Gaspar
mesh_terms: D000179:Acrylates / Q000528:radiation effects; D001565:Benzoates / Q000528:radiation effects; D002851:Chromatography, High Pressure Liquid; D002934:Cinnamates / Q000528:radiation effects; D004355:Drug Stability; D008401:Gas Chromatography-Mass Spectrometry; D010636:Phenols / Q000528:radiation effects; D010782:Photolysis; D011427:Propiophenones / Q000528:radiation effects; D000077185:Resveratrol; D026082:Singlet Oxygen / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013267:Stilbenes / Q000528:radiation effects*; D013473:Sunscreening Agents / Q000528:radiation effects*; D013481:Superoxides / Q000737:chemistry; D014227:Triazines / Q000528:radiation effects; D014466:Ultraviolet Rays; D019207:beta Carotene / Q000528:radiation effects*
chemical_list: D000179:Acrylates; D001565:Benzoates; D002934:Cinnamates; D010636:Phenols; D011427:Propiophenones; D013267:Stilbenes; D013473:Sunscreening Agents; D014227:Triazines; D019207:beta Carotene; D013481:Superoxides; D026082:Singlet Oxygen; C118580:octylmethoxycinnamate; C088673:octocrylene; C466618:octyl triazone; C049935:avobenzone; C439083:bis-ethylhexyloxyphenol methoxyphenyl triazine; D000077185:Resveratrol
keywords: Beta-carotene; Photodegradation; Photostability; Suncreens; Trans-resveratrol