Formulation optimization, skin irritation, and efficacy characterization of a novel skin-lightening agent.

BACKGROUND: Skin-lightening preparations are used by people all over the world for a diverse range of dermatologic indications. The gold standard treatment for skin lightening is with hydroquinone but has been controversial because of the presence of several side effects. Therefore, there has been a constant search for developing new treatment alternatives. Furthermore, the new amendments and bans on animal testing by ECVAM have made the three-dimensional models like EpiDerm(™) and MelanoDerm(™) increasingly popular. OBJECTIVE: This work aims at the formulation development for a new skin-lightening agent, SMA-012, followed by testing for skin irritation and efficacy. METHODS: Formulation parameters such as concentration of SMA-012, amount of ethanol, effect of permeation enhancers and pH were first optimized using Franz cell experiments. Tape stripping and underlying skin assays were performed to analyze the amounts of SMA-012 in different layers of skin. The irritation potential and efficacy of the screened formulation were evaluated using Epiderm(™) and Melanoderm(™) models. RESULTS: Skin permeation experiments suggested that concentrations of 0.1% SMA-012, 35% ethanol, and pH of 8.5 to be the best formulation characteristics. This particular formulation was found to be nonirritant for short-term exposure, when tested in Epiderm(™) model and also significantly effective in decreasing the amount of melanin in pigmented skin equivalent models. CONCLUSION: SMA-012 shows a good promise as a skin-lightening agent for cosmetic and therapeutic applications. Additionally, our study demonstrates the application of skin equivalent models as alternatives to animal testing in studying the regulation of skin pigmentation.

Mushroom tyrosinase inhibitory activity and major fatty acid constituents of Amazonian native flora oils

In order to treat hyperpigmentation-related problems, there has been a global trend in developing cosmetics claiming to have skin-whitening properties, which act by inhibiting melanin biosynthesis. The objective of this work was to evaluate the in vitro mushroom tyrosinase inhibitory activity of five Amazonian native flora oils, and so to verify the possibility of their incorporation into cosmetic products. In addition, the fatty acid composition of the essential oils was determined by gas chromatography-flame ionisation detection in order to determine the main components of these oils. The tyrosinase inhibitory activity of the tested oils was found to be in the following order: açaí (IA50 = 66.08 µg mL-1) > tucumã > patauá > pracaxi > castanha do Brasil. This study suggests that açaí oil has great potential in the treatment of hyperpigmentation and other related disorders, due to its considerable tyrosinase inhibitory activity.

Com o intuito de se tratar problemas dermatológicos de hiperpigmentação, há uma tendência mundial no desenvolvimento de cosméticos que possuam propriedades despigmentantes, os quais agem inibindo a biossíntese de melanina. O objetivo deste trabalho foi avaliar in vitro a atividade de inibição da tirosinase de cogumelo de cinco óleos de plantas nativas da Amazônia e, desta forma, verificar a possibilidade de sua incorporação em produtos cosméticos. Ainda, a composição de ácidos graxos dos óleos foi determinada por cromatografia gasosa com detecção por ionização de chama, no intuito de determinar os principais componentes destes óleos. A atividade de inibição da tirosinase dos óleos testados foi encontrada na seguinte ordem: açaí (IA50 = 66,08 µg mL-1) > tucumã > patauá > pracaxi > castanha do Brasil. Este estudo sugere que o óleo de açaí possui grande potencial para o tratamento da hiperpigmentação cutânea e doenças correlatas, devido à sua considerável atividade de inibição da tirosinase.