Biodegradable polymer microparticle for filler, manufacturing method thereof, freeze-dried body including the same, and filler injection including the same

A biodegradable polymer microparticle group, comprising:

• a first biodegradable polymer microparticle having a core and a shell;
• and
• a second biodegradable polymer microparticle having a core and a shell,
• wherein the cores of the first biodegradable polymer microparticle and the second biodegradable polymer microparticle contain secondary particles including aggregates of a plurality of primary particles,
• wherein the shells of the first biodegradable polymer microparticle and the second biodegradable polymer microparticle have a raspberry shaped structure,
• wherein the first biodegradable polymer microparticle and the second biodegradable polymer microparticle comprise polydioxanone,
• wherein the content concentration in the core of the first biodegradable polymer microparticle is higher than the content concentration in the shell of the first biodegradable polymer microparticle, and the difference in the content concentrations between the core and the shell of the first biodegradable polymer microparticle is 0.01 to 3% by weight,
• wherein the second biodegradable polymer microparticle has the same content concentration in the core and in the shell,
• wherein the content of the second biodegradable polymer microparticle (B) is 6 to 8% by weight based on the total weight of the first biodegradable polymer microparticle (A) and the second biodegradable polymer microparticle (B),
• and wherein the average particle diameter of the plurality of primary particles is 3 to 15 μm, the average particle diameter of the secondary particles is 80 to 150 μm, the cores of the first biodegradable polymer microparticle and the second biodegradable polymer microparticle are 60 to 95% by volume, and the shells of the first biodegradable polymer microparticle and the second biodegradable polymer microparticle are 5 to 40% by volume with respect to the total volume.