A Novel Method for High-Yield Entrapment of Solutes into Small Liposomes

Abstract

A procedure is reported for the high-yield entrapment of a wide variety of solutes in small liposomes. The procedure entails mixing of preformed “empty” (water-filled) small unilamellar vesicles (SLFV) (60-80 nm diameter) with sucrose and the solute destined for entrapment. Using appropriate sugar to lipid mass ratios (eg. 1-5), dehydration of the mixture and subsequent controlled rehydration leads to the formation of vesicles (90-200 nm diameter) entrapping considerable proportions (up to 87%) of the solute. Results with solutes as diverse as penicillin, riboflavin, doxorubicin, desoxyfructo-seroto-nin, and epidermal growth factor suggest that entrapment values depend on the sugar to lipid mass ratio and the identity of the solute but not on the liquid crystalline transition temperature of the phospholipid component of the SUV.

Keywords::

• Liposomes
• Entrapment yield
• Doxorubicin
• Daunorubicin
• Penicillin
• Epidermal growth factor
• Sucrose