Another Reason for Using Caffeine in Dermocosmetics: Sunscreen Adjuvant.

The excessive exposure to ultraviolet (UV) radiation is the main cause of skin cancer, the most commonly diagnosed cancer in the world. In this context, the development of innovative and more effective sunscreens, with bioactive compounds like caffeine, displaying antioxidant and anticancer potential, is required. This research work assessed in vitro and in vivo the efficacy and safety of topical sunscreen formulations containing caffeine as an adjuvant of the UV filters. Sunscreens were prepared with 2.5% w/w caffeine or in the absence of this compound. In order to evaluate the safety of these formulations, stratum corneum hydration, skin barrier and colorimetry were assessed in vivo in healthy subjects before and after skin treatment with the samples. The efficacy of the sunscreens was assessed in vitro, using PMMA plates and a spectrophotometer equipped with an integrating sphere; and in vivo by the determination of the sun protection factor (SPF). None of the formulations caused erythema or impaired the skin barrier function. The in vitro functional characterization showed higher SPF values for the caffeine formulation. The in vivo studies also confirmed the higher SPF value of the formulation combining caffeine with the filters, compared to the caffeine-free sample. This improvement contributed to an increase of, approximately, 25% in the in vivo anti-UVB protection. In conclusion, caffeine was well tolerated by the skin and increased the photoprotective activity, being a new alternative adjuvant in sunscreens formulation.

SPF enhancement provided by rutin in a multifunctional sunscreen.

Unprotected chronic exposure to solar radiation can contribute to premature skin cancer and sunscreens are a key factor to avoid those detrimental effects. Currently, there is a growing interest in the photoprotector and antioxidant potential of bioactive substances, such as rutin, that could increase the sun protection factor (SPF) value and, also, donate multifunctional characteristics to sunscreens. Recent in vitro findings indicated that rutin, when incorporated into sunscreens, can provide antioxidant activity and SPF improvement. However, clinical studies are fundamental to determine this activity, due to the lack of repeatability of in vitro methodology and low correlation with the in vivo data. We aimed at evaluating the clinical safety and in vivo SPF of rutin by comparing sunscreen formulations containing 0.1% (w/w) rutin, 3.0% (w/w) butyl methoxydibenzoylmethane and 8.0% (w/w) octyl dimethyl PABA (2-ethylhexyl 4-(dimethylamino)benzoato) with a similar bioactive-free preparation. Additionally, skin hydration, in vitro SPF and in vitro antioxidant activity of rutin, in association with the ultraviolet (UV) filters, were investigated. The safety profile of the formulations under sun-exposed skin conditions qualified the formulas for clinical efficacy assays. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) test confirmed the antioxidant properties of rutin, revealing around 40% increase in radical scavenging potential when the bioactive compound was present. Rutin in combination with the UV filters robustly elevated the clinical SPF around 70%, when compared with the bioactive-free formulation. To date, this is the first report in the specialized literature of an in vivo SPF measurement of a rutin-containing photoprotective preparation, supporting the claim that rutin is an effective and safe bioactive compound to be used in multifunctional sunscreens.

Ferulic acid photoprotective properties in association with UV filters: multifunctional sunscreen with improved SPF and UVA-PF.

Ultraviolet (UV) radiation stimulates several injurious biological effects on cutaneous tissue, causing, for instance, photocarcinogenesis. Sunscreens are topical products designed to protect the skin against these harmful effects and their use must be encouraged. The addition of antioxidants, as ferulic acid (FA), a phenolic compound from the class of the hydroxycinnamic acids, in sunscreens could improve their sun protection factor (SPF) and prevent inflammatory reactions. Here, the clinical safety and efficacy of an association of ethylhexyl triazone and bis-ethylhexyloxyphenol methoxyphenyl triazine (UV filters) with ferulic acid were assessed. Samples had good skin biocompatibility and presented satisfactory safety profile, even in a sun-exposed condition. A synergic effect between the natural polyphenol and the UV filters was evidenced, as well as, FA increased in vivo SPF in 37% and the UVA protection factor (UVA-PF) in 26%. The in vivo data indicated that FA reinforced the broad-spectrum characteristic of the photoprotective formulations. Additionally, according to the results from the ex vivo antioxidant test, it is plausible to recommend adjustments on the ex vivo protocol to explicitly determine the positive effects of topical antioxidant ingredients applied over the skin. These results provided a new perspective for the development of multifunctional bioactive sunscreens using FA as a new platform.

Latanoprosta e minoxidil: Estudo duplocego comparativo, placebo-controlado no tratamento da queda de cabelos / Latanoprost and minoxidil: comparative double-blind, placebo-controlled study for the treatment of hair loss

Introdução: A latanoprosta tem demonstrado potencial para o tratamento de queda de cabelos devido ao aumento da espessura e do comprimento dos cílios e hipertricose, observados com seu uso na área dos olhos. Objetivo: Avaliar a eficácia da latanoprosta, isolada ou em associações, na redução da queda e/ou estimulando o crescimento de cabelos em pacientes portadores de eflúvio telógeno ou alopecia androgenética. Métodos: Estudo duplo-cego comparativo, durante 180 dias, entre seis grupos: G1: placebo G2: minoxidil 5%; G3: minoxidil 5% + latanoprosta 0,005%; G4: latanoprosta 0,005%; G5: minoxidil 5% + latanoprosta 0,010%; G6: latanoprosta 0,010%. Foi feita a contagem em fototricograma do total e percentual de fios em fase anágena e telógena. Resultados: Houve melhora para os grupos G2 (total de fios e número de fios anágenos em D92 e D180), G3 (total de fios e número de fios anágenos em D242), G4 (total de fios em D182; número de fios anágenos em D92 e D182) e G5 (total de fios em D182; percentual de fios telógenos e anágenos e número de fios anágenos em D92 e D182). O Tratamento do G6 não apresentou diferença significativa em relação ao placebo. Conclusões: Os tratamentos com minoxidil 5%, minoxidil 5% + latanoprosta 0,005%, latanoprosta 0,005%, minoxidil 5% + latanoprosta 0,010% se mostraram eficazes no controle da queda e no aumento total de fios.

Introduction: Latanoprost has been shown to have potential for the treatment of hair loss evidenced by increased thickness and length of eyelashes and hypertrichosis that can be observed when it is used in the periorbital region. Objective: To evaluate the effectiveness of latanoprost, used isolatedly or in associations, for reducing hair loss and/or stimulating its growth in patients bearers of telogen effluvium or androgenic alopecia. Methods: A comparative, double-blind study was carried out during 180 days, with 6 groups: G1 - placebo, G2 - 5% minoxidil, G3 - 5% minoxidil + 0.005% latanoprost, G4 - 0.005% latanoprost, G5 - 5% minoxidil + 0.010% latanoprost, G6 - 0.010% latanoprost. The total and percentage count of hair strands was carried out based on phototrichogram in the anagen and telogen phases. Results: There was improvement in G2 (total number of hair strands, number of anagen strands in D92 and D180), G3 (total number of hair strands and number of anagen hair strands in D242), G4 (total number of strands in D182, and number of anagen hair strands in D92 and D182), and G5 (total number of hair strands in D182, percentage of telogen and anagen hair strands and number of anagen hair strands in D92 and D182). Treatment of G6 did not yield significant difference regarding the placebo. Conclusions: The treatments with 5% minoxidil, 5% minoxidil + 0.005% latanoprost, 0.005% latanoprost, 5% minoxidil + 0.010% latanoprost were shown effective in controlling hair loss and in increasing the total number of hair strands.

Safety and efficacy evaluation of gelatin-based nanoparticles associated with UV filters.

The safety and efficacy assessment of nanomaterials is a major concern of industry and academia. These materials, due to their nanoscale size, can have chemical, physical, and biological properties that differ from those of their larger counterparts. The encapsulation of natural ingredients can provide marked improvements in sun protection efficacy. This strategy promotes solubility enhancement of flavonoids and yields an improved active ingredient with innovative physical, physicochemical and functional characteristics. Rutin, a flavonoid, has chemical and functional stability in topical vehicles exerting a synergistic effect in association with ultraviolet (UV) filters. However, the solubility of rutin is a limiting factor. Additionally, this bioactive compound does not have tendency to permeate across the stratum corneum. As an alternative to common synthetic based sunscreens, rutin-entrapped gelatin nanoparticles were designed. The present study investigated the pre-clinical safety of gelatin nanoparticles (GNPs) using an in vitro method and also assessed the clinical safety and efficacy of the association of GNPs with three commonly used chemical UV filters (ethylhexyl dimethyl PABA, ethylhexyl methoxycinnamate and methoxydibenzoylmethane). The non-irritant and adequate safety profile under sun-exposed skin conditions of the nanomaterials and the emulsions qualified the products for clinical efficacy assays. The in vivo results indicated that the GNPs increased the antioxidant protection of the emulsions developed. However, the presence of rutin in the nanosized material did not enhance performance on the SPF test. In conclusion, these findings characterized the nanomaterials as an innovative platform for multifunctional bioactive sunscreens.

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.

Influence of particle size on appearance and in vitro efficacy of sunscreens

Nanotechnology applies to diverse sectors of science. In cosmetic area, investments have strengthened the idea that nanoproducts provide innumerable benefits to consumers. Extreme exposition to solar light can cause undesirable effects, thus, adding UV filters in cosmetic products are often used as prevention. Ethylhexyl methoxycinnamate and benzophenone-3 are UV filters widely used in sunscreen formulations, this UV filters absorb UVB and UVA radiation, respectively. In this study, sunscreen formulations were developed as nano and macroemulsion, but composed by the same raw material. Nanoemulsion was obtained by phase inversion temperature method (PIT). Physical and functional properties were evaluated by visual analysis, particle size distribution and by diffuse reflectance spectrophotometry. Achieved nanoemulsion showed bluish brightness aspect, less apparent consistency than macroemulsion, stability longer than 48 hours (22.0 ± 2.0 °C) and bimodal particle size distribution with average (mean) sizes around 10 nm (61%) and 4.5 µm (39%). Macroemulsion showed milky aspect, higher consistency than nanoemulsion, instability after 48 hours (22.0 ± 2.0 °C) and bimodal particle size distribution with average (mean) size around 202 nm (9%) and 10.4 µm (91%). Effectiveness profile of sunscreen formulations remained apparently similar, based on achieved results of in vitro SPF, UVA/UVB ratio and critical wavelength assays.

A nanotecnologia se aplica a diversos setores da ciência. Na área de cosméticos, os investimentos têm reforçado a idéia de que nanoprodutos oferecem inúmeros benefícios para os consumidores. A exposição excessiva à luz solar pode causar efeitos indesejáveis, logo, a adição de filtros UV em produtos cosméticos é frequentemente usada como prevenção. O p-metoxicinamato de octila e a benzofenona-3 são filtros UV amplamente utilizados em formulações de protecção solar, que absorvem radiações UVB e UVA, respectivamente. Neste estudo, desenvolveram-se formulações de protetores solares na forma de nano e macroemulsão, mas compostos pelas mesmas matérias-primas. A nanoemulsão foi obtida pelo método da temperatura de inversão de fases (PIT). As propriedades físicas e funcionais foram avaliadas por análise visual, distribuição de tamanho de partículas e por espectrofotometria de reflectância difusa. A nanoemulsão obtida apresentou brilho azulado, menor consistência aparente quando comparada `a macroemulsão, estabilidade superior a 48 horas (22,0 ± 2,0 ° C) e distribuição de tamanhos de partícula bimodal, com média (média) de tamanhos ao redor de 10 nm (61%) e 4,5 µm (39%) . A macroemulsão apresentou aspecto leitoso, maior consistência aaprente do que nanoemulsão, instabilidade após 48 horas (22,0 ± 2,0 ºC) e distribuição de tamanhos de partícula bimodal, com média (média) de tamanhos ao redor de 202 nm (9%) e 10,4 µm (91%). O perfil de eficácia das formulações fotoprotetoras permaneceu aparentemente similar, com base em resultados obtidos por ensaios de FPS in vitro, relação UVA/UVB e comprimento de onda crítico.

Hidrolipodistrofia ginoide: aspectos gerais e metodologias de avaliação da eficácia: [revisão] / Gynoid lipodystrophy: general aspects and methodologies for efficacy evaluation: [review]

A hidrolipodistrofia ginoide (HLDG), popularmente conhecida como celulite, está presente em grande parte da população feminina. Trata-se de umaalteração do relevo cutâneo, envolvendo modificações morfológicas, histoquímicas, bioquímicas e ultraestruturais nos adipócitos, além de alterações na derme e na microcirculação. Existem inúmeras formas de se tratar essa condição, sendo a mais utilizada e de fácil acesso o uso de produtos tópicos contendo princípios ativos com ação vasoprotetora, anti-inflamatória, estimuladores da microcirculação periférica e agentes lipolíticos. Para verificar a eficácia destas formulações, existem metodologias de avaliação envolvendo avaliações instrumentais e clínicas da melhoria do aspecto da celulite. Este artigo teve por objetivo revisar as formas existentes de se avaliar a ação de produtos que atuam na HLDG, considerando os diversos mecanismos de ação, além de revisar aspectos gerais referentes a esta condição.

Gynoid lipodystrophy (HLDG), popularly known as cellulite, is present in a great part of the female population. It is an alteration of the cutaneousrelief involving morphological, histochemical, biochemical and ultrastructural modifications in the adipocytes and also alterations in the dermis andmicrocirculation. There are countless ways of treating this condition, being topic products containing active principles with vessel protective, antiinflammatory actions, peripheral microcirculation stimulators and lipolytic agents the most used and of easiest access. In order to verify the efficacyof these formulations, there are evaluation methodologies involving instrumental and clinical evaluations of the improvement of the aspect of cellulite. Therefore, this article aimed at reviewing the existent ways of evaluating the efficacy of products against gynoid lipodystrophy, taking the different mechanisms of action into account and also at reviewing general aspects concerning this condition.

Comparative study of the stability of free and modified papain incorporated in topical formulations

Papain is an enzyme used in topical formulations as a proteolytic debriding agent for the treatment of open, extensive wounds and burnings. It is also employed as an enhancer for cutaneous permeation of active compounds, chemical peeling and as a progressive depilatory agent. The stability of formulations containing enzymes is not easy. In this research, papain was modified with polyethylene glycol in order to increase the stability of the formulations. The comparative Normal Stability Testing of the topical formulations containing unmodified and modified papain showed that the modified variety presented with a differentiated profile under the adopted temperature conditions (5.0 ± 1.0 °C; 22.0 ± 2.0 °C; 40.0 ± 2.0 °C). The most suitable condition for non-modified papain were 5.0 ± 1.0 °C and, for modified papain, they were 22.0 ± 2.0 °C. These results confirmed the higher stability of modified papain compared to free papain, as well as its potential to be applied in topical formulations.

A papaína é uma enzima utilizada em formulações tópicas como agente proteolítico debridante no tratamento de lesões abertas de grande extensão e queimaduras. É, também, empregada na pele íntegra como agente promotor da permeação cutânea de princípios ativos, peeling químico e como agente depilatório progressivo. A estabilidade de formulações contendo enzimas não é facilmente alcançada. No presente trabalho realizou-se a modificação da enzima com polietilenoglicol, visando maior estabilidade das formulações. A realização do Teste Estabilidade Normal comparativo entre as formulações contendo as formas da enzima não modificada e modificada demonstrou que a última apresentou um perfil de estabilidade diferenciado, nas diferentes condições (5,0 ± 1,0 °C; 22,0 ± 2,0 °C; 40,0 ± 2,0 °C). A condição de 5,0 ± 1,0 °C foi a mais adequada para a formulação contendo papaína não modificada enquanto a 22,0 ± 2,0 °C foi indicada para aquela contendo a forma modificada. Estes resultados confirmaram o aumento da estabilidade da papaína modificada comparada com a livre e seu potencial de aplicação em formulações de uso tópico.

Prospective ultramorphological characterization of human hair by optical coherence tomography.

BACKGROUND/PURPOSE: The continuous advancement in cosmetic science has led to an increasing demand for the development of non-invasive, reliable scientific techniques directed toward claim substantiation, which is of utmost relevance, to obtain data regarding the efficacy and safety of cosmetic products. METHODS: In this work, we used the optical coherence tomography (OCT) technique to produce in vitro transversal section-images of human hair. We also compared the OCT signal before and after chemical treatment with an 18% w/w ammonium thioglycolate solution. RESULTS: The mean diameter of the medulla was 29+/-7 microm and the hair diameter was 122+/-16 microm in our samples of standard Afro-ethnic hair. A three-dimensional (3D) image was constructed starting from 601 cross-sectional images (slices). Each slice was taken in steps of 6.0 microm at eight frames per second, and the entire 3D image was constructed in 60 s. CONCLUSION: It was possible to identify, using the A-scan protocol, the principal structures: the cuticle, cortex and medulla. After chemical treatment, it was not possible to identify the main structures of hair fiber due to index matching promoted by deleterious action of the chemical agent.

Spectroscopic and thermal characterization of alternative model biomembranes from shed skins of Bothrops jararaca and Spilotis pullatus / Caracterização espectroscópica e térmica de biomembranas modelo alternativo de peles galpão de Bothrops jararaca e Spilotis pullatus

Recently, there has been an interest in the use of shed snake skin as alternative model biomembrane for human stratum corneum. This research work presented as objective the qualitative characterization of alternative model biomembranes from Bothrops jararaca and Spilotis pullatus by FT-Raman, PAS-FTIR and DSC. The employed biophysical techniques permitted the characterization of the biomembranes from shed snake skin of B. jararaca and S. pullatus by the identification of vibrational frequencies and endothermic transitions that are similar to those of the human stratum corneum.

Existe atualmente interesse no uso da muda de pele de cobra como modelos alternativos de biomembranas da pele humana. O presente trabalho apresentou como objetivo a caracterização qualitativa de modelos alternativos de biomembranas provenientes de mudas de pele de cobra da Bothrops jararaca e Spilotis pullatus por espectroscopia Raman (FT-Raman), espectroscopia fotoacústica no infravermelho (PAS-FTIR) e calorimetria exploratória diferencial (DSC). As técnicas biofísicas FT-Raman, PAS-FTIR e DSC permitiram caracterizar qualitativamente os modelos alternativos de biomembranas provenientes das mudas de pele de cobra da B. jararaca e S. pullatus e identificar freqüências vibracionais e transições endotérmicas similares ao estrato córneo humano.

Influence of urea, isopropanol, and propylene glycol on rutin in vitro release from cosmetic semisolid systems estimated by factorial design.

Rutin, one of the major flavonoids found in an assortment of plants, was reported to act as a sun protection factor booster with high anti-UVA defense, antioxidant, antiaging, and anticellulite, by improvement of the cutaneous microcirculation. This research work aimed at evaluating the rutin in vitro release from semisolid systems, in vertical diffusion cells, containing urea, isopropanol and propylene glycol, associated or not, according to the factorial design with two levels with center point. Urea (alone and in association with isopropanol and propylene glycol) and isopropanol (alone and in association with propylene glycol) influenced significant and negatively rutin liberation in diverse parameters: flux (microg/cm(2).h); apparent permeability coefficient (cm/h); rutin amount released (microg/cm(2)); and liberation enhancement factor. In accordance with the results, the presence of propylene glycol 5.0% (wt/wt) presented statistically favorable to promote rutin release from this semisolid system with flux = 105.12 +/- 8.59 microg/cm(2).h; apparent permeability coefficient = 7.01 +/- 0.572 cm/h; rutin amount released = 648.80 +/- 53.01 microg/cm(2); and liberation enhancement factor = 1.21 +/- 0.07.

Broad spectrum bioactive sunscreens.

The development of sunscreens containing reduced concentration of chemical UV filters, even though, possessing broad spectrum effectiveness with the use of natural raw materials that improve and infer UV absorption is of great interest. Due to the structural similarities between polyphenolic compounds and organic UV filters, they might exert photoprotection activity. The objective of the present research work was to develop bioactive sunscreen delivery systems containing rutin, Passiflora incarnata L. and Plantago lanceolata extracts associated or not with organic and inorganic UV filters. UV transmission of the sunscreen delivery system films was performed by using diffuse transmittance measurements coupling to an integrating sphere. In vitro photoprotection efficacy was evaluated according to the following parameters: estimated sun protection factor (SPF); Boot's Star Rating category; UVA/UVB ratio; and critical wavelength (lambda(c)). Sunscreen delivery systems obtained SPF values ranging from 0.972+/-0.004 to 28.064+/-2.429 and bioactive compounds interacted with the UV filters positive and negatively. This behavior may be attributed to: the composition of the delivery system; the presence of inorganic UV filter and quantitative composition of the organic UV filters; and the phytochemical composition of the P. incarnata L. and P. lanceolata extracts. Among all associations of bioactive compounds and UV filters, we found that the broad spectrum sunscreen was accomplished when 1.68% (w/w) P. incarnata L. dry extract was in the presence of 7.0% (w/w) ethylhexyl methoxycinnamate, 2.0% (w/w) benzophenone-3 and 2.0% (w/w) TiO(2). It was demonstrated that this association generated estimated SPF of 20.072+/-0.906 and it has improved the protective defense against UVA radiation accompanying augmentation of the UVA/UVB ratio from 0.49 to 0.52 and lambda(c) from 364 to 368.6nm.

Estabilidade e estudo de penetração cutânea in vitro da rutina veiculada em uma emulsão cosmética através de um modelo de biomembrana alternativo / Stability and in vitro penetration study of rutin incorporated in a cosmetic emulsion through an alternative model biomembrane

A rutina é empregada como antioxidante e na prevenção da fragilidade capilar. Estudos de penetração in vitro através da pele humana seria a situação ideal, entretanto, há dificuldades de sua obtenção e manutenção de sua viabilidade. Entre os demais modelos de membrana, a muda de pele de cobra se apresenta como estrato córneo puro, fornecendo barreira similar ao humano e é obtida sem a morte do animal. Os objetivos desta pesquisa foram desenvolver e avaliar a estabilidade de uma emulsão cosmética contendo rutina e, como promotor de penetração cutânea, o propilenoglicol; e avaliar a penetração e a retenção cutânea in vitro da referida substância ativa da formulação, empregando um modelo de biomembrana alternativo. A emulsão foi desenvolvida com rutina e propilenoglicol, ambos a 5,0 por cento p/p. Quantificou-se a rutina das emulsões por espectrofotometria a 361,0 nm, método previamente validado. A penetração e retenção cutânea in vitro foram realizadas em células de difusão vertical com muda de pele de cobra de Crotalus durissus, como modelo de biomembrana alternativo, e água destilada e álcool etílico absoluto 99,5 por cento (1:1), como fluido receptor. O experimento foi conduzido em um período de seis horas, a 37,0 ± 0,5 ºC e agitação constante de 300 rpm. Empregou-se o método espectrofotométrico validado a 410,0 nm para a quantificação da rutina após penetração e retenção cutânea. A emulsão não promoveu a penetração cutânea da rutina através da muda de pele de C. durissus, retendo 0,931 ± 0,0391 mg de rutina/mg de muda de pele de cobra. Nas condições de armazenamento a 25,0 ± 2,0 ºC; 5,0 ± 0,5 ºC e 45,0 ± 0,5 ºC, a emulsão apresentou-se quimicamente estável durante 30 dias. De acordo com os resultados, a emulsão não favoreceu a penetração cutânea da rutina, mas apenas sua retenção no estrato córneo de C. durissus, condição considerada estável no período de 30 dias.

Rutin is employed as antioxidant and to prevent the capillary fragility and, when incorporated in cosmetic emulsions, it must target the action site. In vitro cutaneous penetration studies through human skin is the ideal situation, however, there are difficulties to obtain and to maintain this tissue viability. Among the membrane models, shed snake skin presents itself as pure stratum corneum, providing barrier function similar to human and it is obtained without the animal sacrifice. The objectives of this research were the development and stability evaluation of a cosmetic emulsion containing rutin and propylene glycol (penetration enhancer) and the evaluation of rutin in vitro cutaneous penetration and retention from the emulsion, employing an alternative model biomembrane. Emulsion was developed with rutin and propylene glycol, both at 5.0 percent w/w. Active substance presented on the formulation was quantified by a validated spectrophotometric method at 361.0 nm. Rutin cutaneous penetration and retention was performed in vertical diffusion cells with shed snake skin of Crotalus durissus, as alternative model biomembrane, and distilled water and ethanol 99.5 percent (1:1), as receptor fluid. The experiment was conducted for six hours, at 37.0 ± 0.5 ºC with constant stirring of 300 rpm. Spectrophotometry at 410.0 nm, previously validated, determined the active substance after cutaneous penetration/retention. Emulsion did not promote rutin cutaneous penetration through C. durissus skin, retaining 0.931 ± 0.0391 mg rutin/mg shed snake skin. The referred formulation was chemically stable for 30 days after stored at 25.0 ± 2.0 ºC, 5.0 ± 0.5 ºC and 45.0 ± 0.5 ºC. In conclusion, it has not been verified the active cutaneous penetration through the model biomembrane, but only its retention on the Crotalus durissus stratum corneum, condition considered stable for 30 days.