The effect of additional bitter gourd seed oil on the effectiveness of zinc oxide sunscreen cream

Background: Sunscreen can protect the skin from the harmful effects of ultraviolet (UV) exposure. This study formulated sunscreen cream using a combination of zinc oxide (ZnO) and bitter gourd seed oil. Objective: This study was to determine the effect of adding bitter gourd seed oil in various concentrations on the characteristics of the cream, the effect of irritation on the skin, and the effectiveness of sunscreen in vitro. Method: The ZnO cream combined with bitter gourd seed oil was prepared in various concentrations of F0 (0%), F1 (6%), F2 (9%), and F3 (12%). After that, the physical characteristics and in vitro sunscreen activity were evaluated. Result: The results showed that all formulations met the requirements of organoleptic and homogeneity tests. Cream indicates the type of oil in water (O/W) with a pH of 4.5-8. Spreadability tests are in the range of 5-8 cm, while the irritation test on the skin of the rat's back showed no signs of erythema or oedema. The SPF (Sun protection factors) were 5.64, 10.3, 16.1, and 22.8, with %TE (Erythema transmission) values of 0.983, 0.764, 0.182, and 0.006, while the %TP (Pigmentation Transmission) were 0.981, 0.885, 0.211, and 0.006. LSD results in each test showed that the four formulations had significant differences (p <0.05). Conclusion: The analysis concluded that adding bitter gourd seed oil could increase the in vitro effectiveness of ZnO sunscreen cream preparations and did not cause irritation to the skin.