脂质体被认为是最多功能和先进的纳米粒子传递系统之一，用于将药物靶向送达特定的细胞和组织。在结构上，脂质体是由磷脂分子组成的球形囊泡，周围环绕着相同数量的水相区域。球形的外壳封装了含有肽类、蛋白质、激素、酶、抗生素、抗真菌和抗癌药物等物质的水相内部。脂质体的这种结构特性使其成为药物传递的重要纳米载体。挤压是制备单分散单层脂质体最常用的技术之一，该技术用于控制囊泡的尺寸。该过程涉及将脂质悬浮液通过具有固定孔径的聚碳酸酯膜，以产生与所用膜孔径接近的直径的囊泡。该技术的优点是无需从最终制备物中去除有机溶剂或洗涤剂。本综述主要关注脂质体配方的组成，特别强调影响药物释放和药物负荷的因素。

Liposomes are considered among the most versatile and advanced nanoparticle delivery systems used to target drugs to specific cells and tissues. Structurally, liposomes are sphere-like vesicles of phospholipid molecules that are surrounded by equal number of aqueous compartments. The spherical shell encapsulates an aqueous interior which contains substances such as peptides and proteins, hormones, enzymes, antibiotics, antifungal and anticancer agents. This structural property of liposomes makes it an important nano-carrier for drug delivery. Extrusion is one of the most frequently used technique for preparing monodisperse uni-lamellar liposomes as the technique is used to control vesicle size. The process involves passage of lipid suspension through polycarbonate membrane with a fixed pore size to produce vesicles with a diameter near the pore size of the membrane used in preparing them. An advantage of this technique is that there is no need to remove the organic solvent or detergent from the final preparation. This review focuses on composition of liposome formulation with special emphasis on factors affecting drug release and drug-loading.