Preparation and characteristics of berberine polylactic acid microspheres

Microspheres containing berberine and polylactic acid were prepared by an oil-in-water emulsifying solvent-evaporation process. The proportions of berberine and polylactic acid, dichloromethane and water, and concentration of PVA were taken as the three experimental factors in an L9(34) orthogonal design in order to find the optimum conditions. The distribution of particle sizes, the encapsulation ratio and in vitro release rate were measured. The mean particle diameter was found to be (53.0 ± 3.5) μ m (n=500), the drug loading was (8.96 ± 0.3)% (n=3), and the encapsulation efficiency was (83.4 ± 0.5)% (n=3). The in vitro accumulated release rate of the microspheres was found to be 82.03% after 30 days at 37°C. These data indicate that PLA having molecular weight of 25000 is a suitable material for preparing berberine microspheres for controlled release.