A novel preparation method for PLGA microspheres using non-halogenated solvents

We investigated a new preparation method for microspheres based on an Oil/Water type emulsion solvent evaporation method using non-halogenated solvents. This method is based on phase separation between acetone and aqueous glycerol. For the preparation of microspheres by this method, a solution of poly( dl-lactic-co-glycolic acid) (PLGA) in acetone and aqueous glycerol containing poly(vinyl alcohol) were used as the dispersed and continuous phases in the emulsification process, respectively. Vitamin B 12 was used as the model drug. The formation of PLGA microspheres was observed above 60% glycerol in the continuous phase. The yield and encapsulation efficiency of the PLGA microspheres was about 80%, which was the maximum yield obtained with 70% glycerol. The release of vitamin B 12 lasted for three weeks.