Dissertation > Industrial Technology > Chemical Industry > Pharmaceutical chemical industry > General issues > Basic theory

Relationship between Amphiphilic Chitosan Monolayer and Corresponding Self-assembled Vesicle

Author SuSheng
Tutor LiMingChun
School Huaqiao University
Course Polymer Chemistry and Physics
Keywords N,N-dialkyl chitosan cholesterol monolayer vesicle drug delivery system
CLC TQ460.1
Type Master's thesis
Year 2007
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Vesicles are bilayer supramolecular congeries with structure similar to cell membranes. Their inimitable structures lead them broad usage in drug delivery system, gene delivery and mimetic research. Our research group have successfully prepared N,N-dialkyl chitosan self-assembled vesicles. In this paper, we attempt to investigate the molecular packing behavior of vesicle membrane by using Langmuir monolayer as a facility model.The properties of N,N-dialkyl chitosan monolayers and corresponding vesicles have been investigated by using different kinds of N,N-dialkyl chitosan. With increasing backbone molecular weight and/or lengthen of alkyl chain, the rigidities of N,N-dialkyl chitosan monolayers are enhanced. The longer alkyl chain and/or larger backbone molecular weight of chitosan, the slower drug-releasing rate of chitosan-based vesicles is, and as well as equilibrium drug-releasing ratio. Experimental results indicate that the equilibrium drug-release ratio of N,N-dialkyl chitosan vesicles have a linear relationship with the compressibility of corresponding monolayer.The properties of N,N-dilauryl chitosan monolayer and corresponding vesicle are evidently changed by introducing cholesterol in matrix. The mixed monolayers with lower fraction of cholesterol are less rigid and less compressed than pure N,N-dilauryl chitosan monolayer. As the content of cholesterol increasing, however, the rigidity and compressibility of mixed monolayer is increased. In parallel, both the rate of drug-release and the equilibrium drug-release ratio of the vesicles are increased for those vesicles with cholesterol content less than 40%. It is worthy to notice that they would be decreased when cholesterol content is enlarged. The equilibrium drug-release ratio of the vesicles is decreased with increasing the compressibility of corresponding material monolayer, which has a linear relationship. Accordingly, it is possible to be applied in drug delivery system.

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