Preparation of 20(S)-protopanaxadiol Polylactic Acid-glycolic Acid Sustained Release Microspheres

Objective:To prepare 20(S)-protopanaxadiol polylactic acid-glycolic acid(PLGA)microspheres.Method:20(S)-protopanaxadiol PLGA microspheres were prepared by emulsion-solvent evaporation method,with polyvinyl alcohol(PVA)as emulsifier,mixture of ethyl acetate and methylene chloride as oil phase.Based on single factor test,with composite score of microspheres yield,encapsulation efficiency and drug-loading as index,formulation technology was optimized by orthogonal test,then to investigate its in vitro release characteristics.Result:Optimized formulation technology was as following:volume ratio of O/W 1:50,the mass fraction of PVA 0.5%,feeding dosage 20 mg.These prepared microspheres had round appearance with average particle size of about 1.16 μm,microspheres yield of 35.58%,encapsulation efficiency of 41.76%,drug loading of 19.61%.In vitro release of these microspheres within the first 0.5 h was 18.24%,and cumulative release was up to 98.99% in 192h.Conclusion:This optimized formulation and preparation technology was stable and feasible.These prepared microspheres had significant sustained release effect.