Vesicle size, size distribution, stability, and rheological properties of liposomes coated with water-soluble chitosans of different molecular weights and concentrations

The objectives of this study were to explore the effects of coating with water-soluble chitosans of different molecular weights and concentrations on vesicle size, size distribution, stability, and apparent viscosity of liposomes. The results indicate that the vesicle size of liposomes coated with different concentrations and different molecular weights of water-soluble chitosans decreased with increasing passes of microfluidizing treatment, then reached a constant value. Liposomes subjected to the same microfluidization treatment were larger for those coated with a higher concentration (of the same molecular weight chitosan) or coated with a lower molecular weight (at the same concentration) of water-soluble chitosans. The average particle size of liposomes coated with different molecular weights of water-soluble chitosans decreased with increasing number of passes of microfluidizing treatment. The apparent viscosity of liposomes coated with water-soluble chitosans decreased after the first pass, then reached a constant value after the third pass of microfluidizing treatment. Apparent viscosities of liposomes subjected to different passes of microfluidization treatment were larger for those coated with a higher concentration or a higher molecular weight of water-soluble chitosans, Liposomes coated with 0.5% of different molecular weights of water-soluble chitosans behaved as pseudoplastic fluids. At the same shear rate, the apparent viscosities of liposomes subjected to more passes of microfluidizing treatment were larger than those subjected to fewer passes of microfluidizing treatment. Liposomes coated with water-soluble chitosans are more stable than those without a coating.