In vitro evaluation of sun protection factor (SPF) of manipulated sunscreen cosmetics

Abstract

Aiming to reduce the harmful effects caused on the skin by solar radiation, the use of photoprotectors is a reality these days. Based on the importance of the subject, the objective of this study was to experimentally determine by spectrophotometry in the ultraviolet region the solar protection factor (SPF); to evaluate the macroscopic and physicochemical characteristics of manipulated photoprotectors labeled SPF 30; evidencing the possibility of SPF determination by the in vitro technique as a quality control for compounding pharmacies. The results showed that the formulations appeared to be homogeneous, with normal organoleptic characteristics. The pH remained in the range of 6.30 to 7.66. In the centrifugation test, one of the samples presented slight evidence of inhomogeneity and the others did not show any change in relation to their original appearance. Regarding the SPF in vitro, one of the formulations under evaluation presented a value above the labeling and the others presented lower SPF than those declared on the labels. It is evidenced that the in vitro technique used in the work can contribute to the determination and control of manipulated products since it is a reliable technique.