A method for preparing a polymeric microsphere comprises thesteps of: mixing a water-insoluble organic solvent with adispersion solvent； mixing a polymer compound, a drug and awater-insoluble organic solvent so as to prepare a dispersed phase；mixing the dispersed phase with the dispersion solvent mixed withthe water-insoluble organic solvent so as to prepare an emulsion；and adding a base or an acid to the prepared emulsion so as toremove the water-insoluble organic solvent from the emulsion.Polymeric microspheres prepared by the method can be included incompositions for drug delivery. The present method can generate aminimized amount of waste solution without requiring aconventional solvent-evaporation or solvent-extraction process.Because a low concentration of remaining solvent within a preparedpolymeric microsphere can be maintained, the method can beeffective in the preparation of sustained-release type medicines.
