Desenvolvimento e estudo de estabilidade preliminar de uma emulsão fotoprotetora

Abstract

The sunscreen is a mixture of substances whose role is to prevent the passage of ultraviolet radiation through mechanisms of reflection, refraction and absorption of the same. Research & Development of a broad-spectrum of sunscreen action that can offer significant protection to the skin has been a challenge for the cosmetic area. The objective of this study was to development and evaluate the in the preliminary stability of sunscreen formulation. The formulations F2, F3, F4 and F5 were prepared with different concentrations of Comowax J, cetostearyl alcohol (C.A) and ethoxylated cetostearyl alcohol (E.C.A) at total 6%w/w. The F1 was produced with higher concentration of Cosmowax J (5,6 g/100g of sunscreen) and E.C.A (1,8g/100g of sunscreen). In order to evaluate the effect of incorporation of inorganic filters that can interfere with stability aspects of the formulation was development the batch F3. The in vitro SPF was determined for F1 and F5 according to the spectrophotometric method developed by Mansur et al. (1986). Formulations were stored at 25, 37 and 40°C for fifteen days to investigate their stability. They evaluated the physical appearance, organoleptic characteristics (smell and color), pH, viscosity and centrifugation. The F1, F2 and F3 were stable at room temperature, however, phase separation were observed after centrifugation, as well as, was observed creaming when stored for assessment at temperatures at 37°C. The results suggest that the emulsion has a high degree of wetting and at elevated temperature, the ethoxylates can be easily dispersed in water, break the formulation and become more fluid. Increased in C.A concentration increased viscosity of cream. On the other hand, a good stability was observed for formulations 4 and 5, throughout the experimental period. No phase separation or organoleptic characteristic changes were observed after stored at 37 and 40ºC. This study suggests that F5 with necessary adjustments to optimize the sensory can be considered a safe and effective sunscreen.