PROLONGED RELEASE BIODEGRADABLE MICROSPHERE AND METHOD FOR PRODUCING THE SAME

PROBLEM TO BE SOLVED: To provide a method for producing a pharmaceutical composition in the form of microspheres with prolonged release of a water-soluble active ingredient. SOLUTION: The production method comprises successive steps of: dissolving the active ingredient in an appropriate amount of water, emulsifying the resulting aqueous solution of the active ingredient with a d,l-lactide-co-glycolide matrix copolymer having an average molecular weight ranging between 40,000 and 80,000 and dissolved in a chlorinated hydrocarbon to produce a first microfine and homogeneous emulsion, emulsifying the resulting first emulsion in an external aqueous phase containing a surfactant, a thickener and an osmotic agent, obtaining microspheres by extraction-evaporation of the solvent, and recovering the microspheres after filtering, washing and drying the same. The microspheres can continuously release the active ingredient over a period ranging more than 2 months, advantageously for a period of at least 3 months. COPYRIGHT: (C)2010,JPO&INPIT