Preparation And Characterization Of Fat-soluble Sunscreen Agent Coated With Natural Composite Wall Material

In this study,whey protein and corn starch were used as natural composite wall material to cover the core material with the fat-soluble sunscreen diethylaminohydroxybenzoyl hexyl benzoate.Microencapsulated sunscreen particles were prepared by means of mechanical mixing emulsification and spray drying granulation.The effects of various factors on particle size and embedding of microcapsules,including core wall ratio,whey protein and starch interwall material ratio,emulsifier content,shear rate,shear time and spray drying temperature,were studied.On the basis of single factor test,orthogonal test was carried out to optimize the preparation conditions of key influencing factors,and the optimal preparation conditions were obtained as follows: The core wall ratio was 1:1,the wall material ratio was 1:1,the emulsifier content was 1%,the spray drying temperature was 165 ℃,the shear rate was 13000 rpm and the shear time was 15 min.Under these conditions,the embedding efficiency was 81%,and the sunscreen microcapsules with an embedding rate of 18% could be prepared.The average particle size was 8.17 μm,the particle size distribution was regular,and the morphology was mostly spherical.In addition,the stability and permeability of the coated sunscreen microcapsules were evaluated by simulating human skin in Franz diffusion cell.The prepared microcapsules were tested to leak only about 8.35% of the inner core material diethylaminohydroxybenzoyl hexyl benzoate in 24 h.Using sun protection factor(SPF)values to evaluate the sunscreen effectiveness of the prepared particles,the SPF of the emulsion containing the particles increased by 55.1% compared to the sunscreen containing the same amount of uncoated sunscreen.The experimental results show that the sunscreen effect of coated diethylaminohydroxybenzoyl hexyl benzoate microcapsules is significantly improved compared with that of direct use of free sunscreen.At the same time,the selection of natural wall materials and its natural and environmentally friendly preparation method will have a good application prospect in the production of sunscreen cosmetics.