linoleic-acid and 6-carboxyfluorescein

The effect of the lipid composition of liposomes on their storage for up to one year under different environmental conditions has been examined using 5,6-carboxyfluorescein as a model drug. When cholesterol and/or alpha-tocopherol were included in the liposomes, a significantly greater amount of dye was retained. The presence of alpha-tocopherol decreased the breakdown of phosphatidylcholine to lysophosphatidylcholine and also reduced the level of peroxidation. Carboxyfluorescein retention was further enhanced when liposomes were stored at 4 degrees C or at room temperature (20 degrees C) in an O2-free atmosphere. Lysophosphatidylcholine formation also slowed when the liposomes were kept at 4 degrees C, or in an O2-free atmosphere. It is concluded that egg yolk lecithin liposomes may be stored for long periods at low temperature in an O2-free atmosphere or with added stabilizers such as cholesterol and alpha-tocopherol.

Topics: Chemical Phenomena; Chemistry, Physical; Chromatography, Gas; Drug Stability; Drug Storage; Fatty Acids; Fluoresceins; Linoleic Acid; Linoleic Acids; Lipid Peroxidation; Liposomes; Lysophosphatidylcholines; Phosphatidylcholines; Phospholipids; Vitamin E