Desenvolvimento de nanoemulsão fotoprotetora à base de óleo de linhaça (Linum usitatissimum L.) e de filtros ultravioleta avobenzona e tris-biphenyl triazine (nano)

Abstract

Skin damage caused by solar radiation, such as skin cancer, is known to be reduced by the use of sunscreens. Current efforts on the development of photoprotective formulations are focused on the improvement of those on the market. Accordingly, natural products, e.g., linseed oil, have been used on the development of new sunscreens once they can increase formulations’ photoprotective effect and provide them with additional characteristics, as antioxidant potential. Among different formulations, nanoemulsions are promising systems for this application due to their kinetic stability and possibility of uniform distribution of ultraviolet filters on the skin. The aim of this study was to develop a photoprotective linseed oil-based nanoemulsion with avobenzone and tris-biphenyl triazine (nano) as ultraviolet filters, which in association provide a broad spectrum of ultraviolet protection. The developed nanoemulsion was obtained using 9.9 % of linseed oil, 10 % of surfactants, 0.1 % of avobenzone, 8 % of tris-biphenyl triazine (nano) and 72 % of water. The physicochemical characterization of the nanoemulsion revealed average droplet size of 132.5 ± 8.3 nm, polydispersity index of 0.23 ± 0.03, zeta potential of -23.99 ± 1.28 mv, pH value of 6.77 ± 0.08, electrical conductivity of 1001.33 ± 3.06 µS/cm and in vitro solar protection factor (SPF) of 21. Further, the total content of ultraviolet filters remained stable over time, suggesting a preliminary SPF stability. The results of this study showed that the linseed oil-based nanoemulsion was kinetically stable and that the oil increased the photoprotective effect of the ultraviolet filters mixture, presenting itself as a promising candidate in the sunscreen development field.