Purpose: Amongst the radiations reaching the Earth's surface, the ultraviolet rays are the ones receiving most attention from the scientists, given their damaging potential for humans exposed to them. To minimize the harm caused by such exposure, human beings are strongly recommended to use sunscreens, which are pharmaceutical preparations containing filters that confer protection against radiation. As this protection is strongly dependent on the properties of these filters, it is very important to ensure their stability even when under aggressive conditions, such as the typical high temperatures of summer in South Europe. In this study, a commercial sunscreen emulsion was tested in vitro for a period of time intended to simulate a beach period of 15 days, with regard to the maintenance of its sun protection factor (SPF). Moreover, the organoleptic characteristics were also monitored by macroscopic analysis.
Materials and methods: To perform this study, temperature conditions similar to those observed from June to August in Faro (Portugal) were simulated in vitro. The SPF was determined by spectrophotometry, with subsequent application of the Mansur equation.
Results and conclusion: No significant alterations were observed during the considered period under the specific conditions of this study.
Keywords: Mansur equation; organoleptic characters; sun protection factor; sunscreen; ultraviolet B rays.