PLGA MICROPARTICLES, SUSTAINED RELEASE FORMULATION THEREOF AND METHOD FOR MANUFACTURING SAME

The present application provides approximately spherical lactic acid-glycolic acid copolymer (PLGA) microparticles comprising a biologically active substance, wherein an average volume-based particle diameter of the PLGA microparticles is 1 µm or more and 150 µm or less, and a Reactive Span Factor (R.S.F.) of the PLGA microparticles is satisfied with formula (1): 0.1 < (R.S.F.) ≤ 1.7 formula (1), wherein an R.S.F. means (D90 - D10) / D50; D90 is a particle diameter (µm) corresponding to the cumulative 90% by volume of the cumulative particle diameter distribution from the small particle side; D50 is a particle diameter (µm) corresponding to the cumulative 50% by volume of the cumulative particle diameter distribution from the small particle side; and D10 is a particle diameter (µm) corresponding to the cumulative 10% by volume of the cumulative particle diameter distribution from the small particle side; and an efficient production method thereof. The present invention provides the approximately spherical PLGA microparticles having an average volume-based particle diameter of 1 µm or more and 150 µm or less wherein there are few coarse particles or ultrafine particles without a classification step, and the particle diameter distribution is sharp around the target particle diameter.