ABSTRACT
ABSTRACT Layered double hydroxides have received more attention from researchers due to their range of applications, ease of synthesis and low cost of production. With broader knowledge about solar radiation effects on the body, the use of sunscreens has become even more important. The ability of some nanostructures, such as layered double hydroxides, to act as matrices has made it possible to obtain improvements in photoprotective formulations, with solutions to problems caused by radiation and sunscreens. This review article brings together the most recent advances of these clays, the layered double hydroxides, applied to photoprotection.
RESUMO Os hidróxidos duplos lamelares vêm ganhando maior atenção de pesquisadores, em decorrência da gama de aplicações, da facilidade de síntese e do baixo custo de produção. Com o crescente conhecimento sobre diversos efeitos da radiação solar sobre o organismo, a utilização de fotoprotetores tem se tornado indispensável. A capacidade de nanoestruturas, como os hidróxidos duplos lamelares, atuarem como matrizes possibilitou melhorias nas formulações fotoprotetoras, tendo em vista os problemas provocados pela radiação, bem como por alguns filtros solares. Este artigo de revisão reúne os avanços mais recentes destas argilas, os hidróxidos duplos lamelares, aplicados à fotoproteção.
Subject(s)
Humans , Radiation Protection/methods , Sunburn/prevention & control , Sunscreening Agents/chemistry , Ultraviolet Rays , Nanostructures/chemistry , Hydroxides/chemistryABSTRACT
In the present study, we investigated sun protection factor and antioxidant properties of Parastrephia lepidophyla Cabr., Fabiana squamata Phil., Ephedra chilensis K.Presl., Lampaya medicinalis Phil., Baccharis tola Phil., and Azorella compacta Phil. The ethanol extracts were tested regarding their in vitro free radical scavenger ability and sun protection factor (SPF). Due to its antioxidant and photoprotective properties, B. tola is a promising candidate for use in cosmetic formulations. To evaluate the regenerative capacity of the B. tola extract, the planarian regeneration assay (Dugesia tigrina) was performed. Identification of phenolic compounds in B. tola, was performed by HPLC-ESI-MS/MS. Based on freeze-dried extracts of B. tola, a facial cream and a biphasic lotion with repairing tip action were formulated. These two formulations were evaluated by additional assays including organoleptic tests, measurement of pH, centrifugation and patch test to check a potential hypersensitivity (skin irritation) which can be induced by the products as well as a sensory survey. Stability studies, carried out over 12 months, prove that formulations were stable over time. It can be concluded that both products are innovative and shown solar protection, antioxidant and regenerative properties.
En el presente estudio, hemos investigado el factor de protección solar y propiedades antioxidantes de Parastrephia lepidophyla Cabr., Fabiana squamata Phil., Ephedra chilensis K.Presl., Lampaya medicinalis Phil., Baccharis tola Phil., y Azorella compacta Phil. Los extractos etanolicos fueron sometidos a ensayos como: evaluación in vitro de la actividad atrapadora de radicales libres y factor de protección solar (FPS). Debido a las propiedades antioxidantes y fotoprotectoras, B. tola es un candidato ideal para ser usado en formulaciones cosméticas. Se evaluó la capacidad regenerativa de B. tola en ensayos de planaria (Dugesia tigrina). Se identificó polifenoles por HPLC-ESI-MS/MS en B. tola. Se formularon una crema facial y una loción bifásica reparadora de puntas del cabello, en base a extractos liofilizados de Ñaca, a los cuales se le realizaron controles organolépticos, evaluación de pH, centrifugación, test de parche para evaluar la posible reacción de sensibilidad que pueden ocasionar los productos, comprobando que estos no producen irritación dérmica y posterior encuesta sensorial. Posteriormente, se realizaron estudios de estabilidad a lo largo de 12 meses, demostrando ser estable en el tiempo. Se puede concluir que ambos productos son innovadores y que muestran factor de protección solar, propiedades antioxidantes y regeneradoras.
Subject(s)
Antioxidants/chemistry , Plant Extracts/chemistry , Sunscreening Agents/chemistry , Chile , Chromatography, High Pressure LiquidABSTRACT
Brazil is a country of continental dimensions with a large heterogeneity of climates and massive mixing of the population. Almost the entire national territory is located between the Equator and the Tropic of Capricorn, and the Earth axial tilt to the south certainly makes Brazil one of the countries of the world with greater extent of land in proximity to the sun. The Brazilian coastline, where most of its population lives, is more than 8,500 km long. Due to geographic characteristics and cultural trends, Brazilians are among the peoples with the highest annual exposure to the sun. Epidemiological data show a continuing increase in the incidence of non-melanoma and melanoma skin cancers. Photoprotection can be understood as a set of measures aimed at reducing sun exposure and at preventing the development of acute and chronic actinic damage. Due to the peculiarities of Brazilian territory and culture, it would not be advisable to replicate the concepts of photoprotection from other developed countries, places with completely different climates and populations. Thus the Brazilian Society of Dermatology has developed the Brazilian Consensus on Photoprotection, the first official document on photoprotection developed in Brazil for Brazilians, with recommendations on matters involving photoprotection.
Subject(s)
Humans , Radiation Protection/methods , Sunburn/prevention & control , Sunscreening Agents/administration & dosage , Skin Diseases/prevention & control , Skin Neoplasms/prevention & control , Skin Neoplasms/epidemiology , Solar Energy/statistics & numerical data , Sunburn/epidemiology , Sunscreening Agents/chemistry , Ultraviolet Rays/adverse effects , Vitamin D/metabolism , Brazil/epidemiology , Clothing , Environmental Exposure , Electromagnetic Radiation , Health Promotion/methods , Meteorological ConceptsABSTRACT
In Latin America, people have largely abandoned the practice of wearing hats and traditional clothing that provided skin protection. Sunscreen application has therefore become essential to protect against the increased sun exposure. The physician-prescribed medical-grade sunscreens provide sufficient sun protection but the requirement for regular use puts a financial burden on the patient that is often not sustainable. An appropriate sunscreen should provide a high and broad ultraviolet (UV) protection against UVB and UVA. Several over-the-counter (OTC) sunscreens have been developed for sale at affordable prices and are available for purchase in convenient locations, such as local grocery stores. The aim of this study was to assess the in vitro UV protection of 34 popular OTC sunscreens found in the Latin American market. UV absorbance/transmittance was quantified by diffusion transmission spectroscopy using coarse silica plaques. Photostability was tested by irradiating them with simulated solar light and calculating the sun protection factor (SPF), critical length of absorption (C λ ), UVA/UVB ratio, and the spectral uniformity index (SUI). The results indicated that the in vitro SPFs were significantly lower than the value declared on the labels, particularly for those claiming high SPF values; however, the majority of these sunscreens offered high levels of UV protection. Considering the advantages of low cost and ample accessibility, we concluded that this sample of OTC sunscreens can be beneficial to the general public by providing some level of skin protection from solar radiation, and may be promoted to improve compliance with recommended photoprotection behavior.
En Latinoamérica, la población ha abandonado la costumbre de usar sombrero y ropa tradicional para protegerse del sol. En consecuencia, es básico el uso de protectores solares si se realizan actividades bajo sol. Los protectores solares que se usan en la práctica médica son adecuados, pero su uso frecuente condiciona una carga económica que muchos pacientes no pueden solventar debido a sus costos considerables. Un protector apropiado contiene una amplia y elevada protección ultravioleta (UV) A y B. En las tiendas de conveniencia, existen numerosos protectores solares a precios más accesibles. El objetivo del estudio fue determinar la protección UV in vitro de 34 protectores solares con amplia presencia comercial (de venta sin prescripción médica) en el mercado latinoamericano. La absorbancia/transmitancia de la radiación UV se cuantificó mediante espectroscopía de transmisión difusa. Placas de sílice esmerilado fueron recubiertas con el producto y expuestas a radiación solar simulada para conocer su fotoestabilidad. Se calcularon índices como el factor de protección solar (SPF), longitud crítica de absorción (C λ), relación UVA/UVB y el índice de uniformidad espectral (SUI). Se encontró que el SPF in vitro fue inferior al establecido en las etiquetas, especialmente en aquellos con valores altos. No obstante, la mayoría de los protectores incluidos ofrecen niveles de protección UV elevados. Considerando su amplia accesibilidad y menor costo, concluimos que esta muestra comercial de protectores solares podría utilizarse en el entorno clínico para favorecer su apego junto a las otras medidas de fotoprotección sugeridas.
Subject(s)
Sun Protection Factor , Sunscreening Agents/chemistry , Ultraviolet Rays , Absorption , Advertising , Drug Evaluation, Preclinical/instrumentation , Drug Evaluation, Preclinical/methods , In Vitro Techniques , Latin America , Photochemistry , Quartz , Spectrophotometry , Surface Properties , Sunscreening Agents/radiation effectsABSTRACT
O Fator de Proteção Solar (FPS) é o principal dado para quantificação da eficácia fotoprotetora de um filtro solar, sendo universalmente aceito. Seu método é baseado na determinação da Dose Eritematosa Mínima (DEM), definida como sendo a menor quantidade de energia necessária para o desencadeamento de eritema, em áreas de pele protegidas e não protegidas pelo produto em estudo. O valor do FPS é, então, calculado como a razão numérica entre a DEM da pele protegida e a da pele não protegida. A primeira publicação demonstrando um método para determinação do valor do FPS foi apresentada em 1978 pela agência norte-americana FDA, seguida por outras publicações do próprio FDA e de outras agências regulatórias internacionais. Apesar de ser considerado o método referência para quantificação da eficácia fotoprotetora de produtos tópicos, existem controvérsias na literatura acerca do método para determinação do FPS e sobre as implicações das reais condições de uso na proteção atingida na prática pelos usuários.
The Sun Protection Factor (SPF) is the most important data to quantify the effectiveness of a sunscreen, being universally accepted. The method is based on determining the minimum erythematous dose (MED), defined as the smallest amount of energy required for triggering the erythema, in areas of protected and unprotected skin. The SPF value is then calculated as the ratio between the MED of protected and unprotected skin. The first publication of a method for determining the SPF was presented in 1978 by the U.S. FDA agency, followed by other publications of FDA and other international regulatory agencies. Although considered the reference method for quantification of sunscreen efficacy of topical products, there are controversies in literature about the method for determining the SPF and the implications of the real conditions of use in the protection achieved in practice by users.
Subject(s)
Humans , Erythema/prevention & control , Sun Protection Factor , Sunlight/adverse effects , Sunscreening Agents/chemistry , Ultraviolet Rays/adverse effects , Sunscreening Agents/administration & dosageABSTRACT
As radiaçöes solares alcançam a Terra em forma de ondas. De maior interesse säo as ondas ultravioletas situadas no espectro de 200 a 400 nanômetros, por seu potencial carcinogênico sobre a pele, assim como pela produçäo de fotoenvelhecimento cutâneo e imunodepressäo. Os efeitos dessas radiaçöes sobre a pele dependem da interaçäo de fatores ambientais com fatores de sensibilidade individuais, como fototipo e fotossuscetibilidade. Os fotoprotetores säo agentes com açäo física ou química, que atenuam o efeito da radiaçäo UV por mecanismos de absorçäo, reflexäo ou dispersäo da radiaçäo. A qualidade de um fotoprotetor depende de seu fator de proteçäo solar (FPS) e de suas propriedades físico-químicas (formaçäo de uma película ideal sobre a pele, estabilidade, baixa hidrossolubilidade e hipoalergenicidade). Novos princípios ativos estäo sendo pesquisados, visando a minorar os efeitos adversos desses produtos, como a melanina sintética, o óxido de ferro e as vitaminas antioxidantes. Paralelas à importância da qualidade de um fotoprotetor estäo a reeducaçäo de hábitos e a orientaçäo de seu uso adequado