PROBLEM TO BE SOLVED: To provide sustained release particles excellent in sustained release properties and also in dispersibility, and a method for producing the sustained release particles.SOLUTION: The sustained release particles are obtained by: preparing a hydrophobic solution by dissolving 3-iodo-2-propynyl butyl carbamate (IPBC) in a hydrophobic polymerizable vinyl monomer preparing an aqueous emulsifier solution by blending water and an emulsifier emulsifying the hydrophobic solution in the aqueous emulsifier solution and subjecting the polymerizable vinyl monomer of the emulsified hydrophobic solution to miniemulsion polymerization in the presence of a polymerization initiator and producing a polymer including the IPBC and having an average particle diameter of <1 μm. In the polymer obtained by the miniemulsion polymerization, a dipole-dipole force component δp, polymer of a solubility parameter δ is 5.0-6.0 [(J/cm3)1/2], and a hydrogen bonding force component δh, polymer of the solubility parameter δ is 9.0-9.9 [(J/cm3)1/2].COPYRIGHT: (C)2013,JPO&INPIT【課題】徐放性は元より、分散性にも優れる徐放性粒子およびその製造方法を提供すること。【解決手段】IPBCを疎水性の重合性ビニルモノマーで溶解することにより、疎水性溶液を調製し、水と乳化剤とを配合して乳化剤水溶液を調製し、疎水性溶液を乳化剤水溶液中に乳化させ、乳化された疎水性溶液の重合性ビニルモノマーを、重合開始剤の存在下、ミニエマルション重合して、IPBCを含有する平均粒子径1μm未満の重合体を生成した徐放性粒子であり、ミニエマルション重合により得られる重合体は、溶解度パラメータδの双極子間力項δp,polymerが5.0~6.0[(J/cm3)1/2]であり、溶解度パラメータδの水素結合力項δh,polymerが9.0~9.9[(J/cm3)1/2]である。【選択図】なし
