A Study On Chitosan-based Self-assembled Nanovesicles For Drug Delivery

In this paper the amphiphilic N, N-dilauryl chitosan has first beenprepared by the phase transfer catalysis. The effects of molecular weight ofchitosan and reaction conditions on the substitution degree of alkyl group havebeen studied. The properties of LB film and monolayer of the products werestudied to order to find some fundamental data for making self-assembledvesicles out of this kind of material. The thickness of N, N-dilauryl chitosanmonolayer was measured as 1.74 nm. Two novel kinds of self-assembled nanovesicles have successfully beenprepared by using N, N-dilauryl chitosan with and without additives. Theeffects of molecular weight of chitosan, additives and preparation conditionssuch as pH value of buffer on making self-assembled vesicles have beenstudied. Vitamine B12 as model drug and insulin as applicable drug were usedin our study. The experiments have been done to study the drug-encapsulationefficiency, the drug-loaded content and drug release behavior of variousvesicles. The experimental results show that N, N-dilauryl chitosanself-assembled vesicles can be applied for encapsulation of insulin for itsbigger drug-encapsulation efficiency and longer sustaining time of drug. The products of full acylated chitosan, N-diacyl chitosan and O-diacylchitosan were prepared and characterized in this paper as well. XRDmeasurements were made for above three products and chitosan to investigatethe crystallinity change caused by the acylation. DSC-TG measurements weremade to study their thermo behaviour as well. The O-dilauroyl andO-dipalmitoyl chitosan self-assembled nanovesicles have successfully beenprepared in the study. The experimental results indicate that O-diacylatedlchitosan self-assembled vesicles show two-order of drug release bahaviouraccording to the Fick's formula.