脂质体
脂质体（英语：Liposome）也称为微脂粒，是一种具有靶向给药功能的新型药物制剂。
脂质体是利用磷脂双分子层膜所形成的囊泡包裹药物分子而形成的制剂。由于生物体质膜的基本结构也是磷脂双分子层膜，脂质体具有与生物体细胞相类似的结构，因此有很好的生物兼容性。脂质体进入人体内部之后会作为一个“入侵者”而启动人体的免疫机制，被网状内皮系统吞噬，从而在肝、脾、肺和骨髓等组织中靶向性地富集。这就是脂质体的被动靶向性。
通过在脂质体膜中掺入一些靶向物质，可以使脂质体在生物或者物理因素的引导下向特定部位靶向集中，这就是主动靶向脂质体，目前已经出现的脂质体主动靶向机制有：热敏脂质体、磁导向脂质体和抗体导向脂质体等。
![Liposomes are composite structures made of phospholipids and may contain small amounts of other molecules. Though liposomes can vary in size from low micrometer range to tens of micrometers, unilamellar liposomes, as pictured here, are typically in the lower size range with various targeting ligands attached to their surface allowing for their surface-attachment and accumulation in pathological areas for treatment of disease.[1]](/uploads/202501/24/Liposome0042.jpg)
