PROBLEM TO BE SOLVED: To provide a technique by which effective ingredients are formulated in a preparation to stay stable for a long time and the effective ingredients are slowly released with a controlled rate of release.SOLUTION: The multi-layered coated particle comprises a porous particle which contains effective ingredients, has an average particle size of 50 nm-1 mm, and is covered with a polymer laminated film formed by adsorbing a positively charged polysaccharide polymer and a negatively charged acrylic polymer alternatively. The polymer laminated film functions as a shell to protect the porous particle. The time stability of the effective ingredients against hydrolysis and the like is improved by changing the thickness or the density of the laminated film.COPYRIGHT: (C)2010,JPO&INPIT【課題】薬効成分を製剤中に長期間安定となるように配合させ、かつ薬効成分を徐放させるべく、その放出性を制御できる技術の提供。【解決手段】平均粒径が50nm~1mmで薬効成分を含有する多孔性粒子が、正電荷を有する多糖重合体と負電荷を有するアクリル酸系重合体とを交互に吸着させて形成した重合体・積層膜により被覆された多層被覆粒子を用いる。該重合体・積層膜はその多孔性粒子を保護するシェルとしての機能を有しており、積層膜の厚さや密度を変化させることにより、その薬効成分の加水分解等に対する経時安定性を向上できる。【選択図】図1
