This work focuses on simple methods that allow comparison of the photoprotective effects of sunscreens. One such method described by Mansur and colleagues relies on the spectrophotometric measurements of the organic filters extracted with ethanol. The extracts are subjected to absorbance measurements in the of 290 to 320 nm range, with 5 nm intervals. The sunscreen sun protection factor (SPF) is estimated with an equation that relates each absorbance value with their respective erythemal effect, at the wavelength used for each measurement. In the current work, three commercial sunscreens were assayed using this method, which produced SPF values that were markedly lower than those declared by the manufacturers. These results prompted a more thorough analysis, which concluded that the Mansur method is not suitable for assaying sunscreens with SPFs above 15. The analysis included a survey o...

Universidad Nacional Agraria La Molina. Facultad de Ciencias. Departamento Académico de Biología

Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Nutrición

An assay based on the survival rates of UV-irradiated yeast Saccharomyces cerevisiae cells was used to compare the photoprotectant capabilities of several commercial sunscreens with different sun protection factors (SPFs). Ten lotions with SPF values from 15 to 100 were tested using UVB and UVC irradiations. The results showed that all lotions with SPFs ≥50 exhibited similar photoprotectant capabilities. However, the lotions with SPF 15 and SPF 30 exhibited proportionally lower photoprotection levels. Likewise, the prices per gram of the analyzed lotions were compared, finding them widespread. Since the photoprotection levels of the lotions with SPF values above 50 were equivalent, it could be inferred that other factors are responsible for the variations in the prices, such as the recognition of the brand name, product presentation, marketing strategies, and others. This work shows th...