An irinotecan preparation having irinotecan and/or a salt thereof highly carried by a closed vesicle carrier, which exhibits a strikingly prolonged retention in blood as compared with that of conventional irinotecan liposome preparations and is capable of being present in blood for a prolonged period of time. There is provided an irinotecan preparation comprising closed vesicles formed of a lipid membrane wherein irinotecan and/or a salt thereof is sealed in a concentration of at least 0.07 mol/mol (medicine mol/total membrane lipid mol). The irinotecan preparation preferably has an ion gradient between an inner water phase and an outer water phase within the closed vesicles. The closed vesicles are preferably liposomes, and the liposomes preferably have only the external surface thereof modified with a surface modifier containing a hydrophilic polymer.本發明係有關可提供高載持伊立替康(Irinotecan)及/或其鹽於封閉泡囊載體，比以往公知之伊立替康脂質體製劑更可顯著地提高血中滯留性，可長期存在於血中之伊立替康製劑者。係於脂質膜所形成之封閉泡囊中，以至少0.07莫耳/莫耳(藥劑莫耳/膜總脂質莫耳)之濃度內封之伊立替康製劑。伊立替康製劑係較佳在封閉泡囊之內水相與外水相之間具有離子梯度。封閉泡囊最好係為脂質體，該脂質體係最好為只有外表面以含有親水性高分子之表面修飾劑所修飾者。
