Fotoprotetores – otimização do processo de desenvolvimento, caracterização, estudo de estabilidade e avaliação em modelo animal

Abstract

The importance of using effective and safe sunscreens is an undeniable reality, requiring formulators to obtain enough technical and scientific knowledge to overcome trade barriers. For this purpose was conducted this study using factorial design in the optimization of processes in order to achieve a stable formulation of a sun protection factor (SPF) of medium protection, with action against dermal damage induced by UV radiation. To evaluate the influence of the independent variables (type of wax, emollient and sensory modifier) on the dependent variables (pH, droplet size, conductivity, spreadability, stickiness and FPS), it was elaborated a factorial design 2³ with 8 formulations, which were characterized in relation to the organoleptic and physico-chemical parameters. The results showed that the variables pH, conductivity and viscosity correlated by analysis of variance (ANOVA). Confronting all correlation factors - response, the formulations selected for stability study were F1, F2 and F5. The stability results revealed that F1 significant difference for viscosity (T90 - environment), F2 for viscosity (T60 - environment and refrigerator) and F5 to pH (T90 - environment and ultraviolet light). For registration purposes, it was continued the research on the safety testing required by Anvisa in F1 formulation due to have lower cost. 30 Swiss mice were used (Mus musculus), adult males housed under temperature controlled light / dark cycle of 12 / 12h with standard food and water ad libitum. Animals received UVB irradiation stemmed from a Philips® TL 40W lamp / 12 RS, divided into six groups (n = 5). After being sacrificed it was obtained histologic sections of skin stained with hematoxylin-eosin (HE) and measured the thickness of the skin layers and the number of nucleated cells for each animal. The histopathological results showed that the formulation chosen softened histopathologic skin changes with reduction of sunburn cells, the number of layers of nucleated cells in the epidermis and absence of inflammatory infiltrate in the subepidermal region, obtaining the expected protective effect. At the end the purpose of the study was achieved proving to be a very important work with scientific support, developed by factorial design, a not so used tool in cosmetology area.