Purification Method of Drug-Loaded Liposome
Liposomes are lipid-based bilayer vesicles which can encapsulate drugs to improve their pharmacokinetic performance and thus are widely used as drug delivery system. Drugs loaded in liposomes have distinct pharmacokinetic characteristics from non-encapsulated drugs. Thus, the purification of liposomes, i.e., separating or removing nonencapsulated drugs as well as detergent used in the preparation process, is important for quality control of liposomal products. From a pharmaceutical point of view, well-defined liposome preparations should use well-characterized lipids and would avoid the use of organic solvents and detergents (which are difficult to remove). In this chapter, we reviewed some methods for liposome purification, including dialysis, column chromatographic separation method, centrifugation, protamine aggregation method, ion-exchange resin, and ultrafiltration method. For each method, its basic principle and characteristics are introduced, and some examples are also given. To achieve effective purification, suitable methods should be chosen based on the characteristics of every individual liposome and optimization of separation condition is also demanded. And more efforts needed to be put into the liposome purification field to improve these methods as well as develop other new techniques with a wide range of application.
KeywordsLiposomes Purification Dialysis Column chromatography Centrifugation Protamine aggregation method Ion-exchange resin Ultrafiltration
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