Impact of ferulic acid and resveratrol on the effectiveness and safety of sunscreen

Abstract The combination of avobenzone (AVO) and octyl ρ-methoxycinnamate (OMC) is widely used to ensure broad-spectrum photo-protection because they absorb UVA and UVB, respectively. However, they are thermally and photo unstable because they degrade and undergo photo- tautomerization and trans-cis isomerization, thus reducing their photo-protection efficacy during UV exposure. This study aimed to evaluate the potential use of the antioxidants ferulic acid and resveratrol as stabilizing substances in AVO and OMC mixtures in solution or emulsion. The effects of both antioxidants on the thermal/photo-stability and suppression of the filter singlet state, besides skin permeation, were evaluated. Both antioxidants contributed to preserving OMC and AVO during the thermal stability test, which relates to the maintenance of photo-protection even after storing the formulations at high temperatures. Nevertheless, although resveratrol retained part of the OMC trans isomer and suppressed the AVO singlet state when exposed to UV, no contribution to photo-protection stability was observed, contrary to expectations. Regarding the permeation assay, the addition of both antioxidants was accompanied by a reduction of AVO permeation, while resveratrol increased OMC permeation. Thus, the chemical and physicochemical properties of these antioxidants impacted their efficacy and safety profiles; therefore, further studies are required to establish the real cost-benefit ratio for their use in sunscreens.

Nanoemulsion containing caffeine for cellulite treatment: characterization and in vitro evaluation

The Ginoide Hydrolipodystrophy (GHLD), commonly known as cellulite, occurs in 80-90% of the female population after the puberty period and comes from a metabolic modification in the cutaneous adipose tissue. Caffeine has been used in topical formulations due to its lipolytic action. We studied a nanoemulsion (F3) containing caffeine with two surfactants (oleth-3 and oleth-20) by emulsification method by phase inversion temperature inversion (PIT). The polydispersion indices (PDI) showed the reduced deviation of 0.1. The mean droplet size was ~ 40 nm. The evaluated constant of Ostwald, in the refrigerator condition was the most favorable during the stability test. In the In Raman spectroscopy assay, the caffeine bands found in F3 were compatible with those found in the caffeine solution (1337, 652.5 and 558.2 cm-1). There was no interaction of caffeine anhydrous with other ingredients in nanoemulsion. In the in vitro safety assay the result of 1.4 ranked the F3 as slightly irritating. In the natural membrane, cutaneous permeation test (human skin) permeate concentrations did not exceed the saturation concentration of the PBS buffer (48.96 µg/3 mL). The caffeine solution and F3 permeated statistically equal, but the nanoemulsion visually and sensorially improved the caffeine precipitation.

Influence of different cosmetic vehicles in mechanical and physical properties of hair treated with oxidative hair dyes

ABSTRACT Hair care products play a significant role in the cosmetic market and aim at improving hair brightness, breakage resistance, and color change. In this study, we analyzed the possibility of the formulation of oxidative dyes in different vehicles impacting the hair's both mechanical and physical properties. Light brown and light blond dyes were prepared using eight different vehicles. Among these, four vehicles were emulsifying agents and four gelling agents. Each formulation was applied to two types of virgin Caucasian hair (light blond and dark brown). Physical, chemical, and organoleptic properties of each formulation were assessed, as well as changes in hair parameters after oxidative dyeing, such as staining intensity, brightness, and breaking strength. The parameters of color and brightness differed in some formulations, but the hair type also responded differently. Brightness parameter was increased in dark brown hair colored with both dyes, whereas light blond hair showed the opposite result. Regarding the breaking strength, there were no significant differences between the two kinds of tresses. Cosmetic formulations should adjust the consumer desired effects (e.g. color change) in order to present minimal drawbacks (e.g. decrease of hair brightness and strength). Thus, the study of different vehicles is important when establishing the best oxidative dye formulation.

Desenvolvimento e avaliação de eficácia de nanoemulsão catiônica bioativa na proteção capilar aos danos foto-oxidativos / Development and evaluation of the effectiveness of bioactive cationic nanoemulsion in protecting hair photo-oxidative damage

A radiação solar, composta por radiação ultravioleta (UV), visível (Vis) e infravermelho, é responsável por acelerar os processos de alteração de cor e do conteúdo proteico da fibra capilar. Visando contornar este problema, este trabalho propõe a incorporação do flavonoide quercetina, de reconhecida atividade antioxidante, em uma nanoemulsão catiônica de aplicação capilar. Para tanto, foram desenvolvidas formulações contendo quercetina a 0,5% (p/p) pelo método de baixa energia sub-PIT. A formulação de menor índice de polidispersão (IPD) foi selecionada e submetida à Avaliação de Estabilidade Normal. Neste ensaio, a nanoemulsão foi armazenada em diferentes condições de temperatura por 90 dias, sendo analisados: características organolépticas, valor de pH, atividade antioxidante, conteúdo de quercetina, diâmetro médio de gotícula e potencial zeta. A fotoestabilidade da nanoemulsão envolveu a determinação do perfil de absorção e da sua atividade antioxidante após períodos de exposição à radiação UV/Vis. Posteriormente, a nanoemulsão foi caracterizada quanto aos seguintes parâmetros: eficiência de encapsulamento, perfil reológico, morfologia das gotículas por Microscopia Eletrônica de Transmissão Criogênica e Microscopia de Força Atômica (AFM). A possível interação entre a quercetina e os demais tensoativos presentes na nanoemulsão foi avaliada por Microscopia Confocal de Fluorescência e Análise térmica. A segurança da nanoemulsão foi determinada pelo método in vitro HET-CAM e por biocompatibilidade cutânea, em voluntários. A eficácia da nanoemulsão catiônica na fotoproteção das características da fibra capilar descolorida tratada com tintura cores loiro (12.0) ou ruivo (6.66) foi determinada avaliando-se os parâmetros cor, tração à ruptura, penteabilidade, fricção, perda proteica, morfologia das cutículas e nível de melanina radical por Espectroscopia de Ressonância Paramagnética Eletrônica (EPR), sendo calculado o Fator de Proteção Radicalar (FPR). As mechas de cabelo tingidas foram expostas à radiação UV/Vis artificial (500 W/m2) por até 180 h, sendo os parâmetros analisados antes e após o período de exposição. A nanoemulsão selecionada pelo reduzido IPD apresentava diâmetro médio de gotícula e potencial zeta iguais a 24,97±0,30 nm e 19,6±2,19 mV, respectivamente. Na Avaliação de Estabilidade Normal, a nanoemulsão armazenada a 45,0±2,0° C apresentou alterações significativas de todos os parâmetros avaliados, exceto potencial zeta, sendo que a elevação do diâmetro médio de gotícula acarretou em perda da transparência. A oxidação da quercetina e a instabilidade do tipo Ostwald ripening (ω3) foram as responsáveis pelas modificações observadas. No armazenamento a 5,0±2,0° C, a nanoemulsão manteve todos os parâmetros inalterados, mas a 25±2,0° C houve elevação discreta do diâmetro médio de gotícula, sem perda da funcionalidade. A nanoemulsão apresentou elevada fotoestabilidade, sem alteração da atividade antioxidante após exposição ao UV/Vis. A caracterização da nanoemulsão mostrou que a eficiência de encapsulamento foi de 99,8%, no mínimo, a formulação apresentou típico comportamento newtoniano e as gotículas apresentavam formato esférico. As imagens obtidas por Microscopia Confocal de Fluorescência e o ensaio de Análise térmica mostraram que a quercetina se encontra dentro das gotícula atuando, também, como co-tensoativo, por interagir com os tensoativos, além de exercer sua função antioxidante. A nanoemulsão foi classificada como levemente irritante (método HET-CAM), sendo esse baixo potencial de irritação corroborado pelo teste de biocompatibilidade cutânea. Na avaliação de eficácia, observou-se que a nanoemulsão protegeu a cor total (dE*) do cabelo tingido de loiro em 54%, e elevou a alteração da cor do cabelo tingido de ruivo em 47% (t = 180 h) em comparação à mecha controle. Além disso, a nanoemulsão melhorou a penteabilidade e reduziu os coeficientes de fricção. A radiação UV/Vis provocou elevada perda proteica e redução da espessura das cutículas em aproximadamente 50%. Concluiu-se, pelos resultados obtidos, que as moléculas que compoem a tintura capilar, principalmente os pigmentos mais escuros, atuaram como filtros solares, pois elas protegeram as estruturas proteicas da fibra. A nanoemulsão apresentou FPR igual a 3,31 e 4,14, para as mechas tingidas de loiro e ruivo, respectivamente. O FPR indica a capacidade de uma formulação em reduzir o nível de radicais livres formados por indução da radiação UV/Vis, um dos fatores que induzem alterações na fibra capilar tingida. Assim, considerando que a radiação UV/Vis atua tanto por mecanismos diretos quanto indiretos, e que alterações significativas de cor foram observadas mesmo quando o nível de radicais livres foi reduzido pela ação da quercetina, deve ser incorporada à formulação fotoprotetora capilar filtros solares associados a antioxidantes nanoestruturados. Tais filtros devem ficar aderidos à cutícula, de modo a protegê-la da degradação proteica e reduzir a entrada de radiação para o interior da fibra capilar, local onde os antioxidantes nanoestruturados devem atuar como uma segunda linha de defesa

The solar radiation, comprising ultraviolet (UV), visible (VIS) and infrared, is responsible for accelerating color and protein content changes in the hair fiber. In order to avoid this problem, this work proposes the incorporation of the flavonoid quercetin, a recognized antioxidant molecule, in a cationic nanoemulsion for hair application. For this, formulations containing quercetin 0.5% (w/w) were developed by the low-energy sub-PIT method. The formulation with a lower polydispersity index (PDI), which had HLB value (Hydrophilic-Lipophilic Balance) equal to 12.5 was selected and subjected to the Normal Stability Test. In this assay, the nanoemulsion was stored under different temperature conditions for 90 days, and the following parameters were analyzed: organoleptic properties, pH, antioxidant activity, quercetin content, average droplet diameter and zeta potential. The photostability of the nanoemulsion involved the determination of the absorption profile and its antioxidant activity after periods of exposure to UV/Vis radiation. Subsequently, the nanoemulsion was characterized according to the following parameters: encapsulation efficiency, rheological profile, morphology of the droplets by Cryogenic Transmission Electron Microscopy and Atomic Force Microscopy (AFM). The possible interaction between quercetin and other surfactants present in the nanoemulsion was evaluated by Confocal Fluorescence Microscopy and thermal analysis. The safety of the nanoemulsion was assessed by the in vitro HET-CAM method and by cutaneous biocompatibility in volunteers. The photoprotection effectiveness of the bioactive cationic nanoemulsion was evaluated in blond (color 12.0) and auburn (color 6.66) dyed hair fibers by assessing the parameters: color, tensile break, combing, friction, protein loss, morphology of cuticles and level of melanin radical by Electron Paramagnetic Resonance Spectroscopy (EPR). The Radical Hair Protection Factor (RHF) was calculated. Dyed hair tresses were exposed to UV/Vis artificial radiation (500 W/m2) for 180 h. The parameters were analyzed before and after the exposure period. The nanoemulsion selected due to its reduced PDI had an average droplet diameter and zeta potential equal to 24.97±0.30 nm and 19.6±2.19 mV, respectively. In the Normal Stability Test, the nanoemulsion stored at 45.0 ± 2.0º C showed significant changes in all parameters except zeta potential, and the increase in the average droplet diameter resulted in the loss of transparency. Oxidation of quercetin and Ostwald ripening instability (ω3) were responsible for the changes. At 5.0 ± 2.0º C, the nanoemulsion kept all parameters unchanged, but at 25.0±2.0º C there was a slight increase in the average droplet diameter without loss of functionality. The nanoemulsion showed high photostability since antioxidant activity was not altered after UV/Vis exposure. The characterization of the nanoemulsion showed that the encapsulation efficiency was 99.8% at least, the formulation showed typical Newtonian behavior and droplets were spherical. The images obtained by Confocal Fluorescence Microscopy and thermal analysis showed that quercetin was within the droplet acting, also, as a cosurfactant, due to the interaction with the surfactants. The nanoemulsion was classified as slightly irritating (HET-CAM method), and this low irritation potential was supported by the cutaneous biocompatibility assay. The photoprotective effectiveness evaluation showed that the nanoemulsion protected the total color (dE*) of blond dyed hair in 54%, but raised the color change of auburn dyed hair in 47% (t = 180 h). In addition, the nanoemulsion improved combability and reduced coefficients of friction. UV/Vis radiation caused high protein loss and reduced cuticle thickness by approximately 50%. It was concluded that the molecules that compose hair dye, especially the darker pigments, acted as sun filters because they protected the protein structures of the hair fiber. The nanoemulsion showed RHF equal to 3.31 and 4.14 for blond and auburn dyed hair, respectively. The RHF indicates the ability of a formulation to reduce the level of free radicals formed by UV/Vis induction, one of the factors that induce changes in the dyed hair fibers. Thus, considering that the UV/Vis radiation acts by direct and indirect mechanisms and that significant changes in color were observed even when the level of free radicals has been reduced by the quercetin, chemical filters should be incorporated into hair formulations associated with nanostructured antioxidants in order to fully protect hair fiber. Such filters must be attached to the cuticle, protecting it from protein degradation and reducing the radiation input into the hair fiber, where the nanostructured antioxidants must act as a second line of defense

Stability evaluation of organic Lip Balm

Rising global demand for natural products whose production is harmless to the environment has stimulated the development of natural cosmetics and, within this category, organics (95% organic raw materials). The image of environmentally friendly production is one of the strongest attractions of organic products. Lip balm is a cosmetic product similar to lipstick whose purpose is to prevent lip dryness and protect against adverse environmental factors. The product's characteristics are: resistance to temperature variations, pleasant flavor, innocuousness, smoothness during application, adherence and easy intentional removal. This work involved the development of a lip balm formulated with certified organic raw materials and the execution of stability tests: fusion point determination, evaluation of organoleptic characteristics (color, odor and appearance) and functionality evaluation (spreadability test). The formulation selected after the Preliminary Stability Test was submitted to the Normal Stability Test under the following storage conditions (temperature): Room Temperature (22.0 ± 3.0 ºC), Oven (40.0 ± 2.0 ºC) and Refrigerator (5.0 ± 1.0 ºC), for 90 days. Under the Refrigerator and Room Temperature conditions, spreadability proved adequate, but the surface presented white spots, characterizing the fat bloom, a phenomenon involving the recrystallization of cocoa butter. Storage at 40.0 ± 2.0 ºC (Oven) caused loss of functionality according to the spreadability test, in addition to changes in color, although the aspect was uniform since the fat bloom was not observed (white spots on the surface). The odor remained stable under all conditions as did the melting point, which had a mean of 72.9 ± 1.7 ºC throughout the course of stability testing (90 days).

O aumento da demanda global por produtos naturais, cuja produção não envolva nenhum dano ao meio ambiente, tem estimulado o desenvolvimento de cosméticos naturais e, dentro desta categoria, dos produtos orgânicos (que contêm 95% de matérias-primas orgânicas). O protetor labial é um produto cosmético semelhante ao batom que tem a finalidade de prevenir o ressecamento dos lábios, mantendo a hidratação, e protegê-los contra fatores ambientais adversos. Este trabalho envolveu o desenvolvimento de um protetor labial formulado com matérias-primas orgânicas e avaliação dos parâmetros de estabilidade, como ponto de fusão, características organolépticas e funcionalidade (teste de espalhabilidade). A formulação selecionada após o Estudo de Estabilidade Preliminar foi submetida à Avaliação Normal de Estabilidade, nas seguintes condições de armazenamento (temperatura): Ambiente (22,0 ± 3,0 ºC), Estufa (40,0 ± 2,0 ºC) e Geladeira (5,0 ± 1,0 ºC), por 90 dias. Nas condições de armazenamento em geladeira ou ambiente, a espalhabilidade foi adequada, mas a superfície apresentou pontos esbranquiçados, caracterizando o fenômeno chamado fat bloom, que está relacionado à recristalização da manteiga de cacau. O armazenamento à temperatura elevada (40,0 ± 2,0 ºC) provocou perda de funcionalidade, de acordo com o teste de espalhabilidade, e mudança de cor, apesar do aspecto permanecer uniforme, visto que não foi observado o fenômeno fat bloom. O odor manteve-se estável em todas as condições, assim como o ponto de fusão, com valor médio de 72,9 ºC ± 1,7 ºC durante todo o período de avaliação do teste de estabilidade (90 dias).