engleski

Mucoadhesive chitosan-coated liposomes: characteristics and stability

Lecithin liposomes, empty or containing FITC-dextran, were prepared by the ethanol injection method. Three different types of chitosans with variable molecular weight and degrees of deacetylation were used (Sea Cure 113, Sea Cure 210 and Sea Cure 311). Chitosan coating was carried out by mixing the liposomal suspension with the chitosan solution followed by incubation. The size of liposomes was measured before and after polymer coating by an image analysis technique. Mean diameter of liposomes with FITC-dextran was in the size range between 250-280 nm, whereas the size after the coating was between 300-330 nm, regardless of chitosan type. All chitosan-coated liposomes were of spherical shape and no morphological differences between uncoated and coated liposomes were observed. Liposomes with FITC-dextran, originally entrapping 50 % of the marker taken in the preparation and coated in the presence of unentrapped marker, contained between 60 % to 65 % of the marker. The highest entrapment was determined for liposomes coated with medium molecular weight chitosan. Stability of chitosan-coated liposomes in simulated gastric fluid was significantly higher as compared to uncoated liposomes. By the right choice of chitosan type, it is possible to influence the characteristics of liposomes. One can conclude that chitosan is stabilizing original liposomal structure and protecting entrapped drug.

Mucoadhesion; liposomes; chitosan; mucin; stability

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