Cholesterol-bearing Pullulan Research Articles

Physicochemical Stabilization of Lipid Microspheres by Coating with Polysaccharide Derivatives

Abstract A methodology to improve lipid microspheres (LM) as a carrier for lipophilic drugs and their physicochemical properties are described. The LM were prepared from glycerides, glycerol, and phospholipids. The method involves coating of the surface of the LM with a naturally occurring or chemically modified polysaccharide. Special emphasis will be made on cholesterol-bearing pullulan and amylopectin. This is the same approach as that adopted for the stabilization of liposomes. Turbidity measurement revealed that the coating effectively depressed the Ca2+-induced aggregation of the LM. From fluorescence polarization measurements, it was concluded that the fluidity of the LM surface decreased with the polysaccharide coating. Furthermore, the coating effect was investigated by zeta-potential measurements. The coating reduced the negative zeta-potential of the LM to an apparently neutral value.