N-三甲基壳聚糖包覆的降钙素脂质体的制备及其体内外黏附性质研究

Study on Preparation of N-trimethyl Chitosan Coated Calcitonin Liposome and Adhesion Properties of It in vivo and in vitro

目的:制备N-三甲基壳聚糖(TMC)包覆的降钙素脂质体,考察其理化性质以及体内外黏附性质。方法:采用两步反应法合成TMC;采用薄膜水化法制备降钙素脂质体,并用TMC对脂质体进行包覆,考察其粒径、多分散系数、Zeta电位、包封率及形态;采用猪胃黏膜蛋白微粒结合法评价TMC脂质体在pH4.5、6.8时的体外黏附性质;取大鼠12只,随机分为4组,每组3只,采用C6标记法考察TMC脂质体在十二指肠、空肠、回肠上的体内黏附行为。结果:合成的TMC的季铵化度为78.10%;未包覆的降钙素脂质体带有较强的负电荷,包覆TMC后实现了电荷反转。制得的脂质体外观圆整,包覆层明显,粒径为262.9nm,多分散系数为0.172,Zeta电位为(35.8±1.2)mV,包封率为(89.14±3.1)%。TMC脂质体在pH4.5、6.8时均与黏蛋白纳米粒发生黏附作用,Zeta电位降低。在大鼠体内,2h时,TMC包覆脂质体大部分黏附在小肠上部,尤其是十二指肠部位,到达回肠部位的脂质体较少;4h时,TMC脂质体在各肠段仍然有黏附,但较2h时明显减弱,并以回肠部位基底侧黏附最多。结论:TMC包覆脂质体具有良好的生物黏附性能,可以作为多肽类药物口服递送的新型载体进一步深入研究。

OBJECTIVE：To prepare N-trimethyl chitosan（TMC）coated calcitonin liposome,and to investigate the physicochemical properties and adhesion properties of it in vitro and in vivo.METHODS：2-step reaction was adopted for the synthesis of TMC;calcitonin liposome was prepared by thin-film hydration method,and the liposomes were coated with TMC;the particle size,polydispersity index,Zeta potential,encapsulation efficiency and form were all investigated;the pig gastric mucosal protein particles combination method was used to evaluate in vitro adhesion properties of TMC liposome with pH of 4.5 and 6.8;12 wistar rats were randomly divided into 4 groups,with 3 rats in each group;the adhesion behavior of TMC liposomes to duodenum,jejunum,ileum were investigated by C6 labeling.RESULTS：The degree of quaternization for synthesized TMC was 78.10%;the prepared uncoated calcitonin liposome showed strong negative charge,and charge reversal was achieved after coated with TMC;prepared liposomes was round in appearance and coated obviously with particle size of 262.9 nm,polydispersity index of 0.172,Zeta potential of（35.8±1.2）mV and entrapment efficiency of（89.14±3.1）%;TMC liposomes adhered to mucin nanoparticles under pH 4.5 and pH 6.8 conditions,and reduced the Zeta potential.In rats,at 2 h,most of TMC coated liposome adhered to upper part of small intestinal,especially the duodenum,while less of it adhered to ileum;at 4 h,TMC liposome still adhered to each intestinal segment,but the symptom relieved significantly compared to 2 h,and more adhesion was found in substrate side of the ileum.CONCLUSIONS：TMC coated liposomes show good biological adhesion performance,and can be used as carrier of oral delivery of peptide drugs to carry out further study.