Application Of N,N,N-trimethyl-O,O-Diacyl Chitosan In Self-assembly

Firstly, N, N, N-trimethyl chitosan was prepared by formaldehyde and formic acid method using iodide, and then, N, N, N-trimethyl-O, O-diacylated chitosan derivatives were prepared by octanoyl, docanoyl and dedocanoyl choloride with mesylate. The structures of chitosan derivatives were characterized by infrared spectroscopy, nuclear magnetic resonance to prove that the products were the target products; Element analysis results showed that chitosan derivatives had a high degree of substitution. Thermal gravimetric analysis showed that thermal decomposition temperature and thermal stability of chitosan derivatives decreased. Solubility experiments showed that the N, N, N-trimethyl chitosan had good water-solubility, N, N, N-trimethyl-O, O-diacylated chitosan had good soluble in chloroform solution.Above that, these chitosan derivatives can be applicated in self-assembled microcapsules for a water-solubility drug carrier.Self-assembled vesicles of N, N, N-trimethyl-O, O-diacylated chitosan were prepared by supersonic method. Electron microscopy showed that the shape of vesicles was close to spherical and the particle size ranged from 300nm to 600nm. Self-assembled vesicles of N, N, N-trimethyl-O, O-diacylated chitosan had studied on different main chain of molecular weight and length of side-alkyl chain which impacts the drug release behaviors. UV analysis showed that with the main chain of molecular weight increased, N, N, N-trimethyl-O, O-diacylated chitosan vesicles had a smaller release rate of drug release time, took longer time reach equilibrium and decreased equilibrium release percentage; with length of side-alkyl chain increased, N, N, N-trimethyl-O, O-diacylated chitosan microcapsules had a smaller release rate of drug release time, took longer time reach equilibrium and decreased equilibrium release percentage. Drug encapsulation efficiency and drug loading of N, N, N-trimethyl-O, O-diacylated chitosan had studied on the main chain of molecular weight, length of side-alkyl chain and structure. The results showed that drug encapsulation efficiency increased significantly with the main chain of molecular weight, the length of the side-alkyl chain and charge of cation. Meanwhile, N,N,N-trimethyl-O,O-diacylated chitosan with 1/3 cholesterol(molar ratio) had prepared by the same method. Electron microscope showed that the shape of vesicles were spherical, particle size ranged from 300nm-500nm. With the main-chain molecular weight and length of side-alkyl chain increased, drug release rate slowed down, the balance of release percentage reduced and equilibrium time cutted down. But encapsulation efficiency and drug loading increased slightly, it may be due to cholesterol plays a strong hydrophobic role in N, N, N-trimethyl-O, O-diacylated chitosan microcapsules which have strong positive charge.