Abstract: Purpose: To prepare slow-release erinacines microspheres with poly (lactic-co-glycolic acid) (PLGA) as carry using the emulsification solvent evaporation method and to investigate their release characteristics in vitro. Methods: The one-factor-at-a-time method was adopted to examine the factors affecting encapsulation efficiency, and their levels were optimized using response surface methodology. Results: The optimum preparation conditions were obtained as follows: erinacines to PLGA ratio, 1:1.64 (g/g); concentration of PLGA in dichloromethane, 15%; and stirring speed, 1 200 r/min. The obtained microspheres were complete and smooth with an encapsulation efficiency of 99.66% and a cumulative release rate in vitro of 84.30% in 384 h. Conclusion: The emulsification solvent evaporation method has been successfully applied to prepare erinacines microspheres with high entrapment efficiency and good sustained release performance.

Key words: erinacines, poly (lactic-co-glycolic acid) (PLGA), microspheres, drug release in vitro