中文摘要：

通过羧甲基壳聚糖接枝二甲基十八烷基环氧丙基氯化铵，制备了一系列不同取代度和分子量的羧甲基壳聚糖十八烷基季铵盐（QACMC）．用傅立叶变换红外（FTIR）光谱、核磁共振谱（^1H-NMR）、X射线衍射（XRD）谱、差式扫描量热法（DSC）等对其分子结构、结晶和热性能进行研究，同时研究QACMC的吸湿保湿性能，并与透明质酸（HA）、壳聚糖（chitosan）和羧甲基壳聚糖（CMC）进行比较．结果表明，QACMC具有较好的结晶性和热稳定性，结晶度可达72．3％；其吸湿保湿性低于透明质酸（HA）和羧甲基壳聚糖，而受季铵基团取代度和QACMC分子量的影响，羧酸盐和季铵盐两种亲水基团对QACMC吸湿性的影响不具有协同作用；QACMC对亲脂性药物盐酸米诺环素的载药率可达10．9％（质量分数），远高于壳聚糖和羧甲基壳聚糖．

英文摘要：

A modified approach to prepare novel amphipathic octadecyl-quaternized carboxymethyl chitosan （QACMC） was reported, in which carboxymethyl chitosan （CMC）, prepared from chitosan, was made to react with glycidyl octadecyl dimethylammonium chloride; thus, the octadecyl quaternary ammonium group was introduced into CMC. The structure and thermal properties of these derivatives were characterized by Fourier transform infrared spectroscopy （FTIR）, proton nuclear magnetic resonance spectroscopy （^1H-NMR）, X-ray diffraction （XRD）, and differential scanning calorimetry （DSC）. The crystalline properties of QACMC were perfect, and it had a high degree of crystallinity. All the chitosan derivatives had good thermal stability when the temperature was lower than 200 ℃. The moisture-absorption and retention abilities of QACMC were lower than that of hyaluronic acid （HA） and CMC. The carboxymethyl and quaternary ammonium groups did not show a synergistic effect, and the effects of both the molar mass and the hydrophobic side chains of long alkyl moieties were important. Minocycline hydrochloride was successfully incorporated into QACMC polymeric micelles with a remarkably high efficiency （10.9%, mass fraction）. QACMC promises to be a high-potential delivery vector for lipophilic drugs.