Bemotrizinol-Loaded Carnauba Wax-Based Nanostructured Lipid Carriers for Sunscreen: Optimization, Characterization, and In vitro Evaluation.

Nanostructured lipid carriers (NLC) are aqueous dispersions of nanoparticles formed by solid and liquid lipids. In this study, NLC containing an organic UV filter, bemotrizinol, were developed for sunscreen formulation using carnauba wax and caprylic/capric triglycerides through ultrasonication technique. A Box-Behnken design was used to evaluate the influence of three variables on the particle size with the purpose of choosing the best system for further characterization. The particle size decreased as the surfactant concentration increased, reaching an average size of 122.4 ± 0.3 nm at 30 days of storage. Scanning electron microscopy showed intact and spherical particles. Thermal analysis and Fourier-transform infrared spectroscopy suggest that bemotrizinol was incorporated into the NLC. The X-ray diffraction showed a reduction in the crystallinity of the NLC. In vitro analysis indicated an improvement in the photoprotective activity of bemotrizinol when incorporated into NLC. These findings suggest a promising, stable, and biocompatible system.