[Ultraviolet absorption of prescription sunblocks in Mexico]. / Absorción ultravioleta de los protectores solares para prescripción en México.

ABSTRACT

BACKGROUND: An appropriate sunscreen should provide high and broad ultraviolet protection both for the B and A range. The objective was quantify the ultraviolet absorption spectrum in sunscreens available for medical prescription, and analyze its relationship with the labeled Sun Protection Factor (SPF). MATERIAL AND METHODS: Thirty-nine sunscreens were analyzed in vitro using ultraviolet spectroscopy following exposure to simulated solar irradiation. RESULTS: Fifty-six percent of sunscreens absorbed 90% or more of ultraviolet radiation. Seventy-five percent (n = 34) absorbed more than 95% of ultraviolet B radiation, and 46% (n = 18) more than 90% of ultraviolet A. There was no significant association between ultraviolet absorption and SPF. CONCLUSION: We were unable to estimate ultraviolet absorption only by its SPF. Protection differed considerably among products with similar SPF. Our study highlights regulation deficiencies in marketing practices of these products.