Abstract: Nano-TiO₂ encapsulated with solid lipid nanoparticles was prepared by interface compound generation method,and the formulation was optimized.The influences of blending ratio of emulsifiers sodium stearoyl glutamate (SG) to fatty alcohol polyoxyethylene ether-21 (S21),as well as the mass fraction of solid lipid (docosanol) and liquid lipid (silicone oil 345) on quality and sunscreening performance of the product were studied.Results show that under conditions as:mass fraction of nano-TiO₂,3%;total mass fraction of emulsifiers,8% (in which m(SG)∶m(S21)=2∶1);mass fraction of docosanol,4.5%;mass fraction of silicone oil 345,4.5%;average particle size of solid lipid nanoparticles encapsulated nano-TiO₂ product achieves 219.7 nm,and value of polydispersity index (PDI) achieves 0.221.The system stability of the product is quite good.Comparison of the various influencing factors shows that,for a fixed mass fraction of nano-TiO₂,the blending ratio of the emulsifiers as well as mass fraction of the liquid lipid displays rather big influence on UV absorption performance of the product,while that of solid lipid is not big.

Key words: sunscreen, solid lipid nanoparticles, nano-TiO₂, encapsulation