Abstract:
This study was aimed to explore the stabilizing effect of antioxidants, sodium ferulate and tocopheryl acetate on sun protection factor (SPF) of sunscreen formula. The sunscreen base with SPF 20 was developed (formula 3) and tocopheryl acetate and sodium ferulate were added into formulas 4 and 5, respectively. All formulas were brought to stability testing under five conditions; room temperature, 45 °C, 4 °C, dark place and ambient light for four weeks. At the end of the experiment, physical appearances of all samples are almost the same, except formula 5 storage at 45 °C, which changed odor and its color turned to yellow. The initial SPF value of formulas 3, 4 and 5 were 18.30, 18.34 and 21.20 respectively. The SPF value of the product storage at 45 °C showed the highest reduction of SPF value to 2.29, 6.38 and 9.18 for formula 3, 4 and 5 respectively, followed by ambient light with SPF 5.75, 8.54 and 11.14, room temperature with SPF 9.39, 12.71 and 13.99, at dark place with SPF 10.96, 14.53 and 16.15, and at 4 °C temperature with SPF 11.21, 13.40 and 17.33 respectively. The results indicated that both antioxidants can stabilize photoprotection of sunscreen formula, although sodium ferulate changed the color of formula when storage at high temperature.