The invention provides a polymer microcellular composition which can stably encapsulate medicine and properly release medicine, and a pharmaceutical composition using the polymer microcellular composition.The polymer microcellular composition comprises a block copolymer having a hydrophobic polymer segment 12 and a hydrophilic polymer segment 11.The composition has a structure with a plurality of block copolymers in a radial configuration when the hydrophobic polymer segment 12 is facing the inside and the hydrophilic polymer segment 11 is facing the outside.The composition comprises a block copolymer 10 having affinity with hdl20 as the block copolymer.The composition induces the separation of the block copolymer 10 having affinity with the hdl20 by the adhesion of the affinity hdl20, and forms a gap by the separation, thereby promoting the release of the drug 50 to be encapsulated.Furthermore, the composition further comprises a block copolymer having affinity with lipoproteins other than HDL, thereby controlling the release rate of the drug from the polymer microcellular.本發明係提供一種可穩定地內包藥物且適當釋出藥物的聚合物微胞組合物、以及使用該聚合物微胞組合物之醫藥組合物。該聚合物微胞組合物含有具有疏水性聚合物鏈段12與親水性聚合物鏈段11之嵌段共聚物。該組合物具有複數個該嵌段共聚物於該疏水性聚合物鏈段12面向內側且該親水性聚合物鏈段11面向外側之狀態下成放射狀配置的結構。該組合物含有與HDL20具有親和性之嵌段共聚物10作為該嵌段共聚物。該組合物藉由起因於該親和性之HDL20之附著，而誘導與該HDL20具有親和性之嵌段共聚物10之脫離，藉由該脫離而形成間隙，藉此促進欲內包之藥物50之釋出。又，該組合物進而含有與HDL以外之脂蛋白具有親和性之嵌段共聚物，藉此可控制藥物自聚合物微胞之釋出速度。
