CHARACTERIZATION AND PHASE-BEHAVIOR OF PHOSPHOLIPID-BILAYERS ADSORBEDON SPHERICAL POLYSACCHARIDIC NANOPARTICLES

In this paper a new drug carrier, the Light-biovector, is described. T hese biovectors are composed of a neutral, anionic or cationic polysac charidic core surrounded by phospholipids. They can be prepared with h igh yield and in a nearly pure form as determined by density analysis on sucrose gradients. These particles showed great stability with no s edimentation being observed after more than one year of storage. Physi cochemical studies carried out with dipalmitoylphosphatidylcholine and hosphatidylcholine/dipalmitoylphosphatidylglycerol mixtures showed th at in Light-biovectors, the lipids are organized in bilayer surroundin g the polysaccharidic core. In presence of a neutral polysaccharidic c ore, the gel to liquid phase transition temperature T-m of DPPC was on ly slightly affected as compared to liposomal dispersions of the lipid . In contrast, for cationic and anionic Light-biovectors, the T-m of t he lipids was affected by the electric charge born by the polysacchari dic core, indicating that electrostatic interactions contribute to the organization of the lipid bilayer in these systems. It was also found that the association of anionic membrane- to anionic polysaccharidic cores and the association of cationic membrane to cationic polysacchar idic cores was possible. (C) 1997 Elsevier Science B.V.