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Formaldehyde formic acid method, and methyl iodide was prepared N, N, N-trimethyl chitosan, and on this basis, with methanesulfonic acid as a solvent for the acylation reaction was prepared N, N, N-tris-methyl-O , O-bis acylated chitosan, by infrared spectroscopy, nuclear magnetic resonance to characterize the structure of the product, and to prove the resulting product was a target product; Elemental analysis results indicate that the chitosan derivatives have a high degree of substitution. TGA showed that the synthesized chitosan derivatives with chitosan contrast, found that after modification of the thermal decomposition temperature is lowered, thermal stability decreases. Solubility experiments showed that the N, N, N-trimethyl chitosan has good solubility in water, N, N, N-trimethyl-O, O-bis chitosan has better in chloroform The solubility of the the chitosan microcapsules application on conditions. N, N, N-three methyl-O, O-bis acylated chitosan self-assembled blister through the electron microscope, the morphology of substantially close to spherical, the particle size distribution in the 300nm-600nm. The drug release behavior of the size of the molecular weight of the main chain and the side chain alkyl length of N, N, N-three methyl-O, O-bis acylated chitosan self-assembled blister. With the increase in molecular weight of the main chain, the N, N, N-three methyl-O, O-bis acylated chitosan self-assembled vesicle release rate becomes small, the drug release time to reach equilibrium becomes long to reach equilibrium, release percentage decreases; With the increase of the length of the side chain alkyl, N, N, N-three methyl-O, O-bis chitosan self-assembled vesicle release rate becomes small, the drug release reached equilibrium. time becomes longer, the the release percentage decreases equilibrated. This is due to having a long side chain alkyl and larger chitosan molecular weight of the main chain of the N, N, N-trimethyl-O, O-bis acylated chitosan self-assembled structure vesicle closer. The size of the molecular weight of the main chain, the length of the side chain alkyl and the structure of the different N, N, N-three methyl-O, O-bis acylated chitosan self-assembled blister drug encapsulation efficiency and drug loading has significantly affected. N, N, N-three methyl-O, O-bis acylated chitosan vesicle drug encapsulation efficiency and drug loading volume becomes significant with the increase of the length of the molecular weight of the main chain, side chain alkyl self-assembled large. In addition, N, N, N-three methyl-O, O-bis acylated chitosan self-assembled blister drug encapsulation efficiency and drug loading compared to the O, O-bis acylated chitosan self-assembled large the vesicles drug encapsulation efficiency and drug loading, better. Forming the self-assembly of the N, N, N-trimethyl-O, O-bis acylated chitosan and cholesterol at a molar ratio 2:1 mixed vesicle electron micrograph shows: nearly spherical in shape, particle size and distribution not added cholesterol N, N, N-trimethyl-O, O-bis acylated chitosan similar, but looks relatively dense structure. Main chain of molecular size and the length of the side-chain alkyl N, N, N-trimethyl-O, O-double-acylated chitosan and cholesterol mixed self-assembled vesicles contained vitamin B12 in vitro drug release behavior of certain laws impact. Mainly manifested in: With the increase of the length of the molecular weight of the main chain and side-chain alkyl group, the self-assembled vesicle drug release rate slows down and balanced release percentage decreases, to achieve equilibrium concentration of the time. Cholesterol is added to N, N, N-three methyl-O, O-bis acylated chitosan self-assembled blister drug encapsulation efficiency and drug loading have slightly increased, and this may be due to the strong cholesterol hydrophobic interaction and N, N, N-tris-methyl-O, O-bis chitosan with positive charge strong static electricity has a synergistic effect the result, but the effect is not obvious.
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