Biodegradable extended release microspheres and their preparation process

摘要

Process for preparing a pharmaceutical composition in the form of sustained release microspheres of a water soluble active ingredient, characterized by comprising the succession of the following steps: - dissolving the active ingredient in an appropriate amount of water, said solution of the active ingredient on being without the addition of any substance that retains the active ingredient, or any stabilizing agent emulsion without any operation to increase the viscosity, - emulsify the aqueous solution of the active ingredient thus obtained with a solution of a matrix copolymer d, l-lactide-co-glycolide average molecular weight between 40000 and 80000 and having a ratio lactic acid / glycolic acid ranging from 50/50 to 80/20 acid, dissolved in a chlorinated hydrocarbon, leading to a first homogeneous emulsion and microfine; - emulsifying said first emulsion thus obtained in an external aqueous phase containing 0.1 to 0.5% by weight of polysorbate 80, from 1 to 25% by weight of polyvinylpyrrolidone, and 0.1 to 10% by weight of mannitol or sodium chloride, - extract-evaporate the solvent to obtain microspheres which are recovered after filtration, washing and drying.