Method for preparation of microsphere and apparatus therefor

An apparatus for preparation of microsphere from a medicament-containing polymer solution containing a medicament, a biocompatible and biodegradable hardly-water-soluble polymer and a water-immiscible organic solvent having a boiling point lower than that of water, and an aqueous solution in a closed system, wherein an emulsifying device, a microsphere storage tank and a cross flow filter are set up in the following manner:

• (i) it has a structure by which a medicament-containing polymer solution and an aqueous solution can be introduced into the emulsifying device;
• (ii) the emulsifying device and the microsphere storage tank are connected in such a manner that an emulsion obtained in the emulsifying device can be transferred into the microsphere storage tank having a function of evaporation of organic solvent;
• and
• (iii) the microsphere storage tank, the cross flow filter and the emulsifying device are connected in such a manner that a part of the emulsion contained in the microsphere storage tank is introduced into the cross flow filter, and a liquid passing over the cross flow filter is returned to the microsphere storage tank while a filtrate filtered through the cross flow filter is introduced into the emulsifying device as an aqueous solution.