Phase behavior of phospholipid-cholesterol liposomes stabilized with trehalose

Abstract

Achieving long-term stability in biological systems has been a long-standing goal of the food, pharmaceutical, and biomedical industries. Avoiding the need for refrigeration would reduce production and storage costs drastically. The desiccation of phospholipidic vesicles has been studied in an effort to understand biological membranes under low water content conditions (Crowe and Crowe, 1988; Ohtake et al., 2004). Trehalose is effective in protecting biological membranes upon freeze-drying, and it has been widely used to preserve the integrity of phospholipid liposomes (Crowe and Crowe, 1988; Ohtake, et al., 2004; Crowe et al., 1986). Despite the abundance of cholesterol in mammalian plasma membranes (Rouser, et al., 1968), studies examining the effects of dehydration on cholesterol-containing model membranes are scarce (Van Winden and Crommelin, 1999; Harrigan, et al., 1990). Furthermore, the ability of well known lyoprotectants, such as trehalose, to stabilize cholesterol-containing liposomes has not been examined in detail. The aim of this work is to understand how cholesterol containing liposomes behave upon lyophilization.