Investigation on the Validity of in vitro Sun Protection Factor and Ultraviolet-A Protection Factor Evaluation Method for Sunscreen Samples.

Factors affecting the in vitro Sun Protection Factor (SPF) and Ultraviolet-A Protection Factor (UVA-PF) of sunscreens were analyzed for verifying the validity and reliability of the ISO24443 evaluation method. UV absorbance measurements by different spectrophotometers did not lead to the large difference in in vitro SPF/UVA-PF, although the UV absorbance determined by each spectrophotometer exhibited relatively large difference when it was larger than 2. On the other hand, relatively large difference was found in in vitro SPF/UVA-PF by utilizing European Cosmetic and Perfumery Association (Colipa) 1994 or UV-solar simulated radiation (UV-SSR) for the spectral irradiance. Appropriateness of employing the coefficient of adjustment for the determination of in vitro UVA-PF was also found to be reexamined.

Development and characterization of photoprotective nanoemulsions containing Babassu (Orbignya phalerata Mart. ) lipophilic extract

Abstract Oil-in-water photoprotective nanoemulsions (NEs) were developed using Babassu (BBS) lipophilic extract, nonionic surfactants, and low concentrations of organic sunscreens by ultrasonic processing. BBS extract was chosen due to its suitable physicochemical properties (acidity index, peroxide index, refraction index, and relative density) and predominance of saturated fatty acids, identified by gas chromatography-mass spectrometry (GC-MS), which promote biological activities and high oxidative stability. NEs were characterized by mean droplet size, morphology, polydispersity index (PdI), pH, and organoleptic properties, and the physical stability of the NEs was evaluated for 120 days at room temperature. The sun protection factor (SPF) was determined, and the photostability and in vitro cytotoxicity assays were performed for NEs. All NEs remained stable for 120 days, with a droplet size <150 nm and a monomodal distribution profile. The pH values were compatible with the skin's pH. NE3 showed a spherical morphology, with a mean droplet size of 125.15 ± 0.16 nm and PdI of 0.145 ± 0.032. NE3 containing BBS extract and sunscreens presented an SPF of 35.5 ± 3.0, was photostable after 6 h of radiation and was non-cytotoxic to fibroblast cells. Thus, NE3 could be considered a promising formulation for developing synergic plant-extract sunscreen photoprotective products for the market

New in vitro SPF Evaluation Method for Hydrophilic Sunscreen Samples.

A new method was developed for the in vitro sun protection factor (SPF) evaluation of sunscreen samples. A new type of substrate, a hydroxyalkyl cellulose-coated plate, was also prepared specifically for hydrophilic samples. This new substrate was required because hydrophilic samples would be unlikely to wet the surface of the standard cosmetic PMMA UV evaluation plate. A super-hydrophilic quartz plate was prepared by corona-discharge treatment before an aqueous solution of hydroxyalkyl cellulose was spread on it. A flat and uniform hydroxyalkyl cellulose film was subsequently formed through the evaporation of water. Special care was taken to inhibit the generation of spatial non-uniformity. Six hydrophilic sunscreen samples with in vivo SPF values of 56, 55, 52, 25, 15, and 4, were then applied to the prepared hydroxyalkyl cellulose-coated plate, as well as a super-hydrophilic quartz plate and a flat hydrophobic PMMA plate. The thicknesses of the applied layers were determined using a wheel-shaped wet film thickness gauge immediately after the application, and UV transmission was measured using an SPF analyzer. The value of in vitro SPF was calculated from the UV absorbance and the thickness of the layer. For two out of the six samples, PMMA plate could not be available, as the samples were unable to wet the PMMA surface. Relatively small differences were observed between the in vitro SPF values when the super-hydrophilic and hydroxyalkyl cellulose-coated plates were used. Samples exhibiting higher in vivo SPF were also associated with higher in vitro SPF values, although a linear relationship was not observed. In contrast to the super-hydrophilic plate whose half-life of the super-hydrophilicity is only approximately five days, the hydrophilicity of the hydroxyalkyl cellulose-coated plate scarcely varied during six months of storage. Finally, a simplified evaluation method was also proposed. The validity of the method was verified through a ring test where three researchers employed this method in different laboratories at three independent organizations.

Avaliação de protetores solares contendo filtros encapsulados/incorporados em matriz de sílica mesoporosa ordenada do tipo SBA-15 / Evaluation of sunscreens containing encapsulated/entrapped UV filters in ordered mesoporous silica type SBA-15

Filtros orgânicos são amplamente utilizados em formulações fotoprotetoras, com habilidade de absorver radiações ultravioleta (UV). Contudo, parte destes compostos possuem limitações, como: fotoinstabilidade, permeação cutânea e fotossensibilização e entre outros. Este trabalho envolveu a síntese de matriz mesoporosa do tipo SBA-15, encapsulação/incorporação de ρ-metoxicinamato de octila (MCO), benzofenona-3 (BZF-3) e avobenzona (AVO) na SBA-15 para aplicação em formulações fotoprotetoras. Fez-se a determinação da eficácia in vitro dos filtros encapsulados/incorporados combinados a ingrediente cosmético; o preparo de bastão fotoprotetor e determinação eficácia estimada; a avaliação do potencial de irritação ocular dos bastões por HET-CAM - Hen's Egg Test - Chorioallantoic Membrane, e a avaliação da permeação/retenção cutânea e perfil de biodistribuição dos filtros. Para a caracterização dos materiais foram empregadas técnicas físico-químicas e analíticas. As medidas de adsorção/dessorção de N2 mostrou que as amostras dos filtros solares encapsulados/incorporados apresentaram diminuição na área superficial e volume de poro (V), indicando que os filtros solares foram encapsulados/incorporados na superfície e nos poros da SBA-15. Os resultados de Espalhamento de raios X a baixo ângulo evidenciaram que os filtros solares não afetaram a estrutura hexagonal da SBA-15. Por TG/DTG e análise elementar foi possível determinar a quantidade de filtros solares na superfície e nos mesoporos da SBA-15. Enquanto, as curvas DSC e DTA revelaram aumento na estabilidade térmica da AVO e BZF-3, quando encapsulados/incorporados. Os resultados da eficácia fotoprotetora in vitro mostraram que a combinação dos três filtros solares encapsulados/incorporados na SBA-15 promoveram aumento de 52% no fator proteção solar (FPS), enquanto que, na formulação fotoprotetora contendo os três filtros encapsulados/incorporados, o aumento foi de 94%. O ensaio de HET-CAM evidenciou que os bastões contendo SBA-15 e os filtros encapsulados/incorporados não foram irritantes. O ensaio de permeação/retenção cutânea mostrou que o processo de encapsulação/incorporação da BZF-3 promoveu diminuição de sua permeação em todos os tempos de exposição. As quantidades permeadas de AVO e MCO ficaram abaixo do limite de quantificação nos tempos 6 e 12 h, no entanto, no tempo de 24 h foi possível quantificá-los. As quantidades dos filtros solares retidas na pele a partir da formulação contendo os filtros solares encapsulados/incorporados na SBA-15 (F4) foram menores (tempos 6 e 12 h) em comparação à formulação contendo os filtros solares não encapsulados (F3). A investigação da biodistribuição dos filtros solares mostrou que a retenção total na pele, como na derme, foi menor na formulação F4 em comparação à F3. O estudo comparativo entre pele suína e a pele humana mostrou que as quantidades de BZF-3 e AVO permeadas e retidas na pele suína foram superiores do que em relação à humana para ambas as formulações (F4 e FR). Pela técnica de biodistribuição, foi possível determinar que os filtros solares oriundos das formulações F3 e referência (FR) apresentaram maior retenção destes compostos na derme do que em outras camadas da pele. Contudo, observou-se que os filtros encapsulados apresentaram taxa reduzida de retenção na derme

Organic Filters are chemical compounds widely used in sunscreens formulations with the ability to absorb ultraviolet radiation (UV). Despite the effectiveness of these compounds in UV radiation protection, disadvantages related to their photo instability, potential skin permeation and photo sensibility pose significant challenges for improving these products. The aim of this work was to synthesize mesoporous matrix SBA-15, encapsulation/entrapping of octyl methoxycinnamate (OMC), benzophenone-3 (BZF-3) and avobenzone (AVO) into SBA-15 for application in photoprotective formulations. It was accessed in vitro photoprotection efficacy and in vitro photostability assay of encapsulated/entrapped UV filters combined with cosmetic ingredient and photoprotective stick formulations; evaluation of the ocular irritation potential of photoprotective stick formulations by in vitro method HET-CAM - Hen's Egg Test - Chorioallantoic Membrane; evaluation the skin permeation/deposition and biodistribution profile of photoprotective stick formulations. The decrease in the surface area and in mesoporous volume (V) observed in the nitrogen adsorption desorption isotherms of encapsulated/entrapped samples indicated that UV filters were efficiently encapsulated/entrapped into SBA-15. Additionally, SAXS results showed that UV filters did not affected the hexagonal structure of the mesoporous material and that these compounds filled the SBA-15 pores. TG/DTG and elemental analysis were efficient tools to confirm the presence and the quantity of UV filters into SBA-15. DTA and DSC curves of encapsulated/entrapped materials showed that the thermal stability of AVO and BZF-3 were increased. On the other hand, DSC curves of encapsulated/entrapped materials demonstrated that thermal stability of OMC was not increase. The in vitro photoprotective efficacy results demonstrated that the combination of the three sunscreens encapsulated/entrapped into SBA-15 increased 52.0% the SPF values, while the stick formulation containing the UV filters encapsulated/entrapped, the increase was 94.0%. Delivery experiments using porcine skin demonstrated that the encapsulation/entrapping process of UV filters resulted the decreased of BZF-3 permeation and deposition in skin (6 and 12 hours). The cutaneous biodistribution profile of UV filters showed that the deposition of these compounds from encapsulated/entrapped stick formulation (F4) was significantly lower than that from UV filters stick formulations (F3) in the total slices of the skin and dermis. The comparative study between porcine skin and human skin demonstrated that the amounts of BZF-3 and AVO permeated and deposited in porcine skin were higher than in human skin for both formulations (F4 and FR - reference formulation). By the biodistribution technique it was possible to determine that the UV filters from the formulations F3 and FR presented higher retention of these compounds in the dermis than in other layers of the skin. On the other hand, it was observed that the encapsulated UV filters presented low retention rate into dermis

The 'Dispersal Rate' - a product dependent characteristic to predict the reliability of the calibrated in vitro SPF on WW5 plates.

OBJECTIVES: The evaluation of the SPF by the measurement of light transmission through a thin film on PMMA plates is an interesting alternative to the conventional in vivo method. However, during the last years an internationally acknowledged in vitro SPF measurement could not be established mainly due to bad reproducibility. With this work, we would like to give new suggestions for an improved reproducibility and to open new space for discussion. METHODS: A total of 22 o/w emulsions with well-established in vivo SPF were measured in vitro close to the international Standard ISO 24443 on two different substrates (PMMA plates: WW5 and HD6). For each product, the ratio 'in vitro SPFraw /in vivo SPF' was calculated. The composition of the products was analysed regarding a parameter that correlates with the aforementioned ratio. Additionally seven suitable calibration products were determined to transfer the in vitro SPFraw to the calibrated in vitro SPFcal . RESULTS: We could show that the results for the SPFcal matched very well for 19 measured o/w emulsions on WW5 plates. However, we found two products where the in vitro SPF was much lower than the in vivo SPF. The Dispersal Rate allows us to identify a product characteristic parameter to predict too low measured in vitro SPFs on WW5 plates. This parameter mainly refers to the ratio of water to lipids in an emulsion. We found that products with few emollients and few emulsifiers are measured too low in vitro. CONCLUSION: We suggest implementing an individual calibration of the in vitro SPF to improve the reproducibility of in vitro SPF measurements between different laboratories. Considering the Dispersal Rate helps to estimate the reliability of the in vitro SPF measured on WW5 plates. In order to evaluate whether those products with a high Dispersal Rate can also be calibrated with special standards, further measurements need to be done. We demonstrate that, besides the known parameter, also the composition of the products should be considered for the interpretation of the in vitro SPF. Our findings could explain some multiple reported problems in correlation between in vitro and in vivo SPF, especially for higher SPFs (Personal Care, November, 2014, 27).

In vitro and in vivo photoprotective/photochemopreventive potential of Garcinia brasiliensis epicarp extract.

The damaging effects of sunlight to the skin has triggered studies that involve the synthesis and extraction of organic compounds from natural sources that can absorb UV radiation, and studies on polyphenolic compounds with antioxidant and anti-inflammatory properties that can be used as photochemopreventive agents for reducing skin damage. We investigated the in vitro and in vivo photoprotective/photochemopreventive potential of Garcinia brasiliensis epicarp extract (GbEE). We evaluated the cell viability of L929 fibroblasts after UVB exposure using a quartz plate containing the extract solution or the GbEE formulation. The in vivo photoprotective effect of the GbEE formulation was evaluated by measuring the UVB damage-induced decrease in endogenous reduced glutathione (GSH), the increase in myeloperoxidase (MPO) activity and secretion of cytokines IL-1ß and TNF-α. The in vitro methodology using fibroblasts showed that the photoprotective properties of the GbEE solutions and 10% GbEE formulation were similar to the commercial sunscreen (SPF-15). In vivo results demonstrated of the GbEE formulation in decreasing UVB induced-damage such as GSH depletion, an increased in MPO activity and secretion of cytokines IL-1ß and TNF-α. The results showed that the extract has great potential for use as a sunscreen in topical formulations in addition to UV filters.

Avaliação do fator de proteção solar (FPS) in vitro e perfil reológico de fotoprotetores comerciais infantis / Assessment of in vitro Sun Protection Factor (SPF) and rheological profile of commercial infant sunscreens

A pesquisa tem como objetivo a aplicação da transmitância espectral utilizando uma esfera de integração para estimar o Fator de Proteção Solar (FPS) de fotoprotetores comerciais para o uso infantil. Fotoprotetores com FPS 30 (A, B e C), disponíveis comercialmente, foram selecionados para avaliação conforme as seguintes metodologias: valor de pH, perfil reológico, e valor de FPS in vitro por espectroscopia. As amostras A, B e C apresentaram, respectivamente, os seguintes valores de pH: 7.8, 7.4 e 7.0. O perfil reológico identificou os sistemas como semissólidos pseudoplásticos não-Newtonianos, com área de histerese. O teste-T (p < 0.05) foi utilizado para confrontar o FPS alegado (FPS = 30) com o estimado por espectroscopia. Estudos in vitro foram considerados de grande importância para a área cosmética, podendo corroborar, previamente, a realização dos estudos de eficácia in vivo. De acordo com os resultados, as amostras A, B e C apresentaram valores de FPS sem diferença estatisticamente significativa, quando comparados àqueles citados nos rótulos. A transmitância espectral utilizando esfera de integração provou ser uma metodologia conveniente, rápida e reprodutível para a avaliação estimada do FPS.

This research focused on the measurement of spectral transmittance using an integrating sphere to estimate the Sun Protection Factor (SPF) of commercial sunscreens oriented for child use. Commercially available SPF 30 sunscreens (A, B and C) were selected and assessed by the following methodology: pH measurement; rheological profile analysis; and in vitro SPF estimation by spectroscopy. Samples A, B and C exhibited, respectively, pH values of 7.8, 7.4 and 7.0. The rheological profile identified the systems as pseudoplastic non-Newtonian semisolids with hysteresis loops. The t-test (p < 0.05) was used to confront the claimed SPF (SPF = 30) with that estimated by spectroscopy. In vitro tests are considered of utmost importance in the cosmetic , since their results may be used to validate submission to subsequent in vivo efficacy experiments. According to our results, sunscreens A, B and C generated SPF values without any significant difference from those claimed on the commercial sunscreen labels. The measurement of spectral transmittance with an integrating sphere proved to be a convenient, fast and reproducible method for SPF estimation.

Síntese e avaliação da segurança in vitro da rutina e do succinato de rutina visando sua incorporação em formulações fotoprotetoras eficazes associados a filtros químicos e físico / Synthesis and in vitro safety evaluation of rutin and rutin succinate aiming their incorporation into effective sunscreens associated with chemical and physical filters

A tendência atual do mercado cosmético é desenvolver produtos que contenham insumos de origem vegetal. O objetivo deste trabalho foi a aplicação da Tecnologia da Química Verde na síntese da rutina visando o aumento da estabilidade dessa em formulações cosméticas com sua eficácia antioxidante e fotoprotetora. Realizou-se a síntese química por meio da introdução de grupos carboxilatos às hidroxilas do dissacarídeo na molécula de rutina, gerando como produto final o succinato de rutina. Este derivado e/ou a rutina foram incorporados em 74 formulações-teste e, selecionadas 12 (sistemas emulsionados O/A), após serem submetidas à Avaliação Preliminar de Estabilidade (APE) e ao Teste de Estabilidade Acelerada (TEA), sob variações de temperatura e umidade. Utilizou-se agentes emolientes e silicones para facilitar a solubilização e/ou dispersão dos filtros químicos e físicos. A segunda etapa deste trabalho foi a avaliação da segurança do succinato de rutina, tendo como padrão a rutina, por meio do método alternativo de toxicidade in vitro, o XTT. Após o screening das concentrações ensaiadas, as que apresentaram menor nível de morte celular foram respectivamente, 0,1% ou 1 mg/mL (rutina) e 0,4% ou 4 mg/mL (succinato de rutina). Segundo os resultados do TEA, as formulações contendo succinato de rutina associada ou não aos filtros solares em ambas as bases cosméticas (A - Crodafos®CES + Uniox®C e B - Hostacerin®SAF) foram selecionadas para a continuidade do Teste de Estabilidade Normal (TEN). Neste teste, as emulsões fotoprotetoras foram avaliadas frente aos parâmetros: propriedades organolépticas (aspecto, cor e odor), aspectos físico-químicos (medição de pH e de viscosidade) e funcionais (atividade antirradicalar e eficácia fotoprotetora in vitro). Os resultados apresentados pela formulação MS (succinato de rutina associado aos filtros químicos e físico) foram: homogeneidade, a não modificação de cor e odor em temperatura ambiente, a não alterações significativas...

The current cosmetic market trend is to develop products containing vegetables raw materials. This work proposed to use the Technology of Green Chemical to increase the rutin stability in cosmetic formulas as regards of its antioxidant and photoprotective properties. The chemical synthesis was realized by the introduction of carboxylate groups on sugar moiety of rutin producing in rutin succinate. This derivative and/or rutin were incorporated into 74 test formulas. After the undergoing to preliminary and accelerated stabilities under different temperature and humidity conditions were selected 12 formulas (O/W emulsions). Emollient agents and silicones were used to improve the solubility and/or dispersion of the chemical and physical filters. The second stage of this work was to evaluate the safety of rutin succinate, rutin used as an internal standard, using the alternative method of in vitro toxicity, the XTT. After the screening of tested concentrations, the concentrations of the samples with the lowest level of cell death were 0.1% or 1 mg/mL (rutin) and 0.4% or 4 mg/mL (rutin succinate), respectively. According to results obtained in accelerated stability testing, the formulations containing rutin succinate in combination or not with UV filters in both O/W emulsions (A - Crodafos®CES + Uniox®C and B - Hostacerin®SAF) were selected for the long term stability test. In this test the sunscreens were evaluated in the following parameters: the organoleptic properties (appearance, color and odor), physico-chemical aspects (pH value and viscosity) and functional (antiradicalar activity and in vitro photoprotection efficacy). The results presented by the MS formula (rutin succinate associated with physical filter and chemical filters) were: uniformity, stability of color and odor at room temperature and showed no significant difference, as well stability in: pH and SPF (Sun Protection Factor) values, hysteresis area, antiradicalar activity. These results were...

In vitro Sun Protection Factors (SPFs) of Sunscreen and Skin Irritability / 대한피부과학회지

BACKGROUND: Use of suncreen is strongly recommended to prevent the harmful effect by ultraviolet (UV) ray, and new diverse synthetic chemicals have been screened and put forward as effective UV filters. However, the most important aspect of developing a novel UV filter is safety. OBJECTIVE: This study aimed to find out if there was any correlation between a high in vitro SPF (Sun Protection Factor) index and skin irritation by using standardized formulations containing organic or inorganic, active sunscreen ingredients. METHODS: HRIPT (Human repeated insult patch test) was conducted on with fifty subjects (male to female ratio as 3: 2, average age was 21.6+/-2.9 years), and in vitro SPFs of sunscreen formulations were measured. Patch tested UV filters (UVA, UVB, and physical blockers) were butyl methoxy dibenzoyl methane (BMDM 2%, 5%), benzophenone-3 (2%, 5%), homosalate (10%, 20%), octyl methoxy cinnamate (10%, 20%), octyl salicylate (5%, 10%), octocrylene (10%, 20%), zinc oxide (10%, 20%)and titanium dioxide (10%, 20%). Skin bioengineering measurements for capacitance, erythema, laser doppler blood flow were carried out before and after HRIPT to compare the subjective observation errors of the conventional scoring system of skin irritation (ICDRG standard). To explore any photoirritability, phototoxicity or photoallergy, individual UV filters were photopatch tested with higher concentrations (5%, 20%) than those of usual photopatch sunscreen test series RESULTS: The range of in vitro SPF revealed from 3.6 to 52.8. A doubtful, rather transient, weak erythema (+0.5) was noted in eight subjects, though the apparent skin irritation reaction can be estimated at over +1 by ICDRG guideline was not found during the HRIPT. The weak erythemas were observed at 20% homosalate, 10% octyl salicylate, 5% octyl salicylate, 20% octyl methoxycinnamate, 10% octyl methoxycinnamate, 10% octocrylene, 20% octocrylene, 5% BMDM, respectively in frequency, thus UVB filters of high concentration were related to weak irritation. Nosignificant differences in the measured skin bioengineering parameters were detected between before and after the HRIPT. Photopatch test failed to find any photoirritability and photoallergy. CONCLUSION: Skin irritability due to high in vitro SPFs appeared to be minimal or remained within the safety margin. However, a weak irritation was suspected from the organic UVB filters under the higher concentration range than its recommended range by regulatory guidelines. As for the newly developed, diverse formulations of multi-organic UV filters claiming high SPFs, dermatologists could consider the potential irritation reactions when it is preferentially used within a population.