Abstract: N-methyl-N,N-didodecyl chitosan (TMC) was synthesized. The obtained chitosan derivative was characterized by FTIR，EA and solubility method. N-methyl-N,N-didodecyl chitosan self-assembled vesicles were prepared by the ethanol injection method. Zeta potential of the vesicles ranged from 39.5 mV to 49.5 mV，particle diameter ranged from 50 nm to 100 nm，diameter distribution ranged from 0.17 to 0.26，and the vesicles were very stable for a period of 30 days. The Langmuir behavior of TMC indicated that the lower the pH，the easier the self-assembly. Different pH values of preparation medium had a large effect on the particle size and drug release behavior of the vesicles. However，different pH values of release medium had little effect on the drug release behavior.

Key words: surfactants, preparation, nanoparticles, vesicles, ethanol injection

摘要： 以壳聚糖为原料制备N-甲基-N,N-双十二烷基壳聚糖盐酸盐（TMC），用FT-IR、EA对产物进行表征，溶解性实验表明TMC溶于乙醇等有机溶剂。采用乙醇注射法制备TMC囊泡，研究不同pH值介质中制得的载亲/疏水药物TMC囊泡的Zeta电位、粒径大小及分布、储存稳定性、载药及释放性能。结果表明，制得的TMC自组装囊泡Zeta电位为39.5～46 mV，粒径为50～100 nm，多分散系数为0.17～0.26，静置30天后仍保持稳定。Langmuir膜行为表明在较低pH值下TMC更易自组装，制备介质pH值不同对囊泡的粒径、药物释放行为影响较大，而释药环境pH值对囊泡的药物释放行为影响较小。

关键词: 表面活性剂, 纳米粒子, 囊泡, 粒度分布, 乙醇注射法