RESUMO
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.
Assuntos
Estilbenos/efeitos da radiação , Protetores Solares/efeitos da radiação , Raios Ultravioleta , beta Caroteno/efeitos da radiação , Acrilatos/efeitos da radiação , Benzoatos/efeitos da radiação , Cromatografia Líquida de Alta Pressão , Cinamatos/efeitos da radiação , Estabilidade de Medicamentos , Cromatografia Gasosa-Espectrometria de Massas , Fenóis/efeitos da radiação , Fotólise , Propiofenonas/efeitos da radiação , Resveratrol , Oxigênio Singlete/química , Espectrofotometria Ultravioleta , Superóxidos/química , Triazinas/efeitos da radiaçãoRESUMO
This study aimed to assess the phototoxic potential of combined UV-filters and retinyl palmitate (RP) in the presence or not of bemotrizinol (BMTZ), employing photostability and in vitro and in vivo phototoxicity assays. The formulations tested contained octocrylene (OCT), octyl methoxycinnamate (OMC), benzophenone-3 (BZP-3) and RP (photostable) or octocrylene (OCT), octyl methoxycinnamate (OMC), avobenzone (AVO) and RP (less photostable). Both formulations were supplemented with bemotrizinol. Photostability was evaluated by exposing, or not, formulations spread on a glass plate to UVA/UVB irradiation. The resulting products were quantified by HPLC analysis. In vitro phototoxicity of UV-filters and combinations were evaluated using 3T3 viable monolayer fibroblast cultures submitted, or not, to irradiation according to OECD TG 432. In vivo photoallergy and photoxicity were assessed by clinical studies (photopatch test). Photostability assays showed that UV-filter bemotrizinol was a better photostabilizer for RP/benzophenone-3 than for RP/avobenzone. The in vitro phototoxicity of the combination RP/avobenzone was reduced by bemotrizinol. Clinical studies did not indicate phototoxic or photoallergenic potentials in all formulations tested. It is concluded that the 3T3 NRU phototoxicity test may be considered a supplementary assay in formulation developments, since it can detect chemically unstable and potentially phototoxic combinations. However, extrapolation of in vitro positive results to human photopatch tests may be performed only to a limited extent.
Assuntos
Dermatite Fotoalérgica/etiologia , Dermatite Fototóxica/etiologia , Fenóis/efeitos adversos , Protetores Solares/efeitos adversos , Triazinas/efeitos adversos , Vitamina A/análogos & derivados , Células 3T3 , Acrilatos/efeitos adversos , Acrilatos/farmacologia , Acrilatos/efeitos da radiação , Adolescente , Adulto , Idoso , Animais , Benzofenonas/efeitos adversos , Benzofenonas/farmacologia , Benzofenonas/efeitos da radiação , Cinamatos/efeitos adversos , Cinamatos/farmacologia , Cinamatos/efeitos da radiação , Diterpenos , Método Duplo-Cego , Interações Medicamentosas , Estabilidade de Medicamentos , Humanos , Camundongos , Pessoa de Meia-Idade , Vermelho Neutro/metabolismo , Fenóis/farmacologia , Fenóis/efeitos da radiação , Ésteres de Retinil , Medição de Risco , Protetores Solares/farmacologia , Protetores Solares/efeitos da radiação , Triazinas/farmacologia , Triazinas/efeitos da radiação , Raios Ultravioleta , Vitamina A/efeitos adversos , Vitamina A/farmacologia , Vitamina A/efeitos da radiação , Adulto JovemRESUMO
STATEMENT OF PROBLEM: The color alteration of resin-based materials is one of the most common reasons to replace esthetic dental restorations. PURPOSE: This study assessed the influence of surface sealant (Biscover) on the color stability of nanofilled (Supreme XT) and microhybrid (Vit-l-escence and Opallis) composite resins after artificial aging. MATERIAL AND METHODS: One hundred disc-shaped (6 × 1.5 mm) specimens were made for each composite resin. After 24 hours, all specimens were polished and sealant was applied to 50 specimens of each material. Baseline color was measured according to the CIE L*a*b* system using a reflection spectrophotometer. Ten specimens of each group were aged for 252 h in an ultraviolet (UV)-accelerated aging chamber or immersed for 4 weeks in cola soft drink, orange juice, red wine staining solutions or distilled water as control. Color difference (ΔE) after aging was calculated based on the color coordinates before (baseline) and after aging/staining treatment. Data were analyzed with 2-way ANOVA and Fisher's test (α=.05). RESULTS: The results showed significant changes in color after artificial aging in all the groups (P<.05). Independent of the material studied, red wine resulted in the highest level of discoloration. Intermediate values were found for orange juice, UV accelerated aging, and the cola soft drink. The lowest values of ΔE were found for specimens stored in distilled water. CONCLUSIONS: All composite resins showed some color alteration after the aging methods. The surface sealant did not alter the color stability of the tested materials.
Assuntos
Acrilatos/efeitos da radiação , Resinas Compostas/efeitos da radiação , Restauração Dentária Permanente , Pigmentação em Prótese , Cimentos de Resina/efeitos da radiação , Descoloração de Dente/prevenção & controle , Análise de Variância , Teste de Materiais , Espectrofotometria , Raios Ultravioleta/efeitos adversosRESUMO
Development of photostable sunscreens is extremely important to preserve the UV protective capacity and to prevent the reactive intermediates of photounstable filter substances behaving as photo-oxidants when coming into direct contact with the skin. Thus, the objective of this study was to evaluate the photostability of four different UV filter combinations in a sunscreen by using HPLC analysis and spectrophotometry. The formulations that were investigated included four different UV filter combinations often used in SPF 15 sunscreens. The UV filter combinations were: octyl methoxycinnamate (OMC), benzophenone-3 (BP-3) and octyl salicylate (OS) (formulation 1); OMC, avobenzone (AVB) and 4-methylbenzilidene camphor (MBC) (formulation 2); OMC, BP-3 and octocrylene (OC) (formulation 3); OMC, AVB and OC (formulation 4). In the photostability studies, 40 mg of each formulation were spread onto a glass plate and left to dry before exposure to different UVA/UVB irradiation. Exposed samples were then immersed in isopropanol and the dried film dissolved ultrasonically. The filter components in the resulting solution were quantified by HPLC analysis with detection at 325 nm and by spectrophotometry. In this study, the four UV filter combinations showed different photostability profiles and the best one was formulation 3 (OMC, BP-3 and OC), followed by formulations 4, 1 and 2. In addition, OC improved the photostability of OMC, AVB and BP-3.