Nanostructured lipid carrier (NLC) coated with two sunscreens

benzophenone-3 (BP-3) and octyl methoxycinnamate (OMC)

was prepared by high pressure homogenization. The effects of the total oil content

liquid lipid content

sunscreen content

as well as the emulsifier type and dosage on the particle size

zeta potential and entrapment efficiency of NLC were investigated by single-factor experiments

and the technical formula was optimized. Moreover

the effects of electrolyte type and concentration as well as the amount of emulsifier on the aggregation behaviors of NLC were further investigated and the dynamic model was established. The results show that the electrolyte can compress the electric double layer of the colloid system and decrease the zeta potential

which also aggravate the aggregation and binding between the nanoparticles. The critical coagulation concentrations of NLC samples in the inorganic electrolyte solutions of NaCl and CaCl2 were 538.2 and 95.8 mmol·L-1

respectively. And the aggregation rate of NLC in the solution of CaCl2 is faster than that in NaCl solutions. Besides

the proper amount of the emulsifier is also helpful to maintain the stability of the NLC system.