Abstract:

Nanolipid carriers and traditional emulsion containing chemical sunscreens were prepared using emulsification combined with ultrasonic technology. The nanolipid carriers showed superior performance in sunscreen encapsulation, slow release and skin impermeability, and provided an excellent nanolipid slow-release encapsulation system for sunscreens. As observed by transmission electron microscopy, the nanolipid carriers were spherical shape, with smooth surface and uniform distribution, and the particle sizes were mainly concentrated in the range of 230 to 250 nm without agglomeration. The nanolipid carriers significantly improved the sunscreen performance through the synergistic effect of scattering and chemical absorption, and showed better UV stability than traditional sunscreen, indicating their photoprotective function. In vitro release experiments showed that the nano-lipidic carriers exhibited better release control when loaded with octyl methoxycinnamate （OMC） and butylmethoxydibenzoylmethane （BDFM） sunscreens than traditional traditional emulsions, with the cumulative release rate of OMC in the nano-lipidic carriers decreasing by 17.17% to 30.24% within 12 hours, and that of BDFM decreasing by 26.67% to 44.67%. 26.67% to 44.16%. The results of the in vitro permeation experiment further confirmed that the nanolipid carriers could effectively encapsulate the sunscreens and prevent them from penetrating the skin barrier, thus reducing the skin irritation. Compared with traditional traditional emulsion, the cumulative penetration of OMC in nanostructured lipid carriers was 2.24 μg/cm² in 4 hours, while the cumulative penetration was reduced by 68.05%. The cumulative penetration of BDFM in the nanostructured lipid carrier was 3.24 μg/cm², with a 64.04% reduction in cumulative penetration.

Key words: nano lipid carrier, sunscreen agents, photostability, in vitro sustained-release properties, extracorporeal permeability