Formulation of sunscreens with enhancement sun protection factor response based on solid lipid nanoparticles

Solid lipid nanoparticle (SLN) was regarded as new topical delivery systems for pharmaceutical and cosmetic active ingredients. The purpose of this study is to develop carrier systems for organic and inorganic sunscreens based on a matrix composed of carnauba wax and decyl oleate. Formulae (F1–F7) were prepared using butyl methoxydibenzoylmethane and octyl methoxycinnamate as organic components, and titanium dioxide (TiO₂) was used as inorganic component. Both types of sunscreens were incorporated into SLN formulations using classical method of preparation. To evaluate the effect of the pigments on the nanoparticles, particle size was measured using Mastersizer particle size analyser. UV‐protection abilities of formulations were investigated by the in vitro sun protection factor test (SPF). Further parameters determined were spreadability as well as viscosity. The rheological behaviour of the formulations was also carried out. From the plot of log of shear stress vs. log of shear rate, the slope of the plot representing flow index and ontology of the y‐intercept indicating consistency index was calculated. The formulae showed a flow index of 0.2074–0.4005 indicating pseudoplastic flow behaviour. Significant increases in SPF values up to about 50 were reported after the encapsulation by using organic and inorganic filters in Canada wax and decyl oleate. So, SLN could be appropriate vehicles to carry organic and inorganic sunscreens. The rational combination of cinnamates, titanium dioxide and Zinc oxide has shown a synergistic effect to improve the SPF of cosmetic preparations.