Patent ID: 11617720

Abstract:
The present application provides a microsphere in which a main agent is uniformly dispersed in a polymer matrix, wherein an average volume-based particle diameter of the microsphere is 1 μm or more and 150 μm or less, and a variation coefficient of area ratios in four regions is 0.35 or less, wherein the area ratios in four regions are calculated by (s/A)×100(%) wherein the four regions are prepared by preparing a cross section observation sample obtained by cutting the microsphere; observing the cross section observation sample with an electron microscope at a magnification capable of confirming the main agent in the microsphere or a higher magnification; and dividing the electron microscope observation image into four regions; and A is an area of a respective divided region, and s is a sum of cross section areas of the main agent included in the respective divided region. The microsphere of the present invention can appropriately control the initial release amount of the main agent and its release rate during a subsequent release period, and can continuously release the main agent for a predetermined period of time.