Liposomes encapsulating polymeric chitosan based vesicles — a vesicle in vesicle system for drug delivery

Abstract

Drug delivery systems comprising vesicles prepared from one amphiphile encapsulating vesicles prepared from a second amphiphile have not been prepared previously due to a tendency of the bilayer components of the different vesicles to mix during preparation. Recently we have developed polymeric vesicles using the new polymer-palmitoyl glycol chitosan and cholesterol in a 2:1 weight ratio. These polymeric vesicles have now been encapsulated within egg phosphatidylcholine (egg PC), cholesterol (2:1 weight ratio) liposomes yielding a vesicle in vesicle system. The vesicle in vesicle system was visualised by freeze fracture electron microscopy. The mixing of the different bilayer components was studied by monitoring the excimer fluorescence of pyrene-labelled polymeric vesicles after their encapsulation within egg PC liposomes or hexadecyl diglycerol ether niosomes. A minimum degree of lipid mixing was observed with the polymeric vesicle-egg PC liposome system when compared to the polymeric vesicle-hexadecyl diglycerol ether niosome system. The polymeric vesicle-egg PC vesicle in vesicle system was shown to retard the release of encapsulated solutes. 28% of 5(6)-carboxyfluorescein (CF) encapsulated in the polymeric vesicle compartment of the vesicle in vesicle system was released after 4 h compared to the release of 62% of encapsulated CF from plain polymeric vesicles within the same time period.

Biomolecule–polymer hybrid compartments: combining the best of both worlds

“…18 An early example for a multicompartment vesicle showed as well the inverse configuration by encapsulating polymersomes inside a bigger liposome without providing any specific functionality. 157 In contrast, polymersomes were introduced very recently as subcompartments into giant plasma membrane vesicles (GPMVs) to form molecular factories. 142 GPMVs are giant vesicles directly isolated from cells.…”

The Level of Hydrophobic Substitution and the Molecular Weight of Amphiphilic Poly-L-lysine-Based Polymers Strongly Affects Their Assembly into Polymeric Bilayer Vesicles

“…Polymeric vesicles show increased retention of dissolved solutes (14) and an increased resistance to solubilization by alcohol (18) or bile salts (9). Additionally, polymeric vesicles prepared from palmitoyl glycol chitosan have recently been encapsulated within phosphatidylcholine liposomes and show a reduced degree of lipid mixing with these liposomes (19).…”

Preparation and Characterization of Large Unilamellar Vesicles Mixed With Trimethylchitosan (TMC): The Effect of Polyelectrolyte Concentration

“…By combining chitosan and liposomal characteristics, specific, prolonged, and controlled release can be achieved [5 -7]. A solid polymeric vesicle, namely palmitoyl glycol chitosan, was entrapped within a liposomal formulation to control the release profiles of a model compound [8]. A small degree of mixing of the lipids occurred upon hydration of the lipid/surfactant film, resulting in a vesicle formulation instead of a vesicle in vesicle system [8].…”

“…A solid polymeric vesicle, namely palmitoyl glycol chitosan, was entrapped within a liposomal formulation to control the release profiles of a model compound [8]. A small degree of mixing of the lipids occurred upon hydration of the lipid/surfactant film, resulting in a vesicle formulation instead of a vesicle in vesicle system [8]. The results showed that the polymeric vesicle phospholipid in vesicle system released 28% of the entrapped model compound compared to 62% from the polymeric vesicles over the duration of 4 hours [8].…”