A delayed release coating comprising a mixtur e of a first material selected from starch amylase amylopectin chitosan chondroitin sulfate cyclodextrin dextran pullulan carrageenan scleroglucan chitin curdulan and levan, and a second material which has a pH threshold at about pH5 or above, is used to target release of a drug from a core to the intestive, particularly the colon.本發明提供一種緩釋包衣,包括第一物質和第二物質的混合物,而該第一物質係選自澱粉、直鏈澱粉、支鏈澱粉、殼聚醣、硫酸軟骨素、環糊精、右旋醣苷、普魯蘭多醣體、卡拉膠、小核菌葡聚醣、甲殼素、膠體態葡聚醣以及果聚醣,而該第二物質具有pH值5或pH值5以上的pH臨界值,該緩釋包衣係用來使核心中之藥物可對腸部位,特別是結腸進行靶向釋放。
