壳聚糖修饰的雷公藤甲素聚乙二醇-聚乳酸纳米粒的制备及质量评价

 目的制备壳聚糖修饰的雷公藤甲素聚乙二醇-聚乳酸纳米粒，并对其质量进行评价。方法通过降解反应合成低相对分子质量壳聚糖，采用黏度测定法和酸碱滴定法测定其黏均相对分子质量和脱乙酰度；以聚乙二醇-聚乳酸为载体材料，低相对分子质量壳聚糖为修饰剂，采用乳化溶剂挥发法制备壳聚糖修饰的雷公藤甲素聚乙二醇-聚乳酸纳米粒；并比较壳聚糖修饰前后纳米粒的性质；以纳米粒形态、粒径、Zeta电位、包封率、载药量及体外释放度为指标评价其质量。结果壳聚糖的黏均相对分子质量为20000，脱乙酰度为90%；经壳聚糖修饰后，纳米粒的粒径和Zeta电位均增大，包封率几无变化；所制备的纳米粒外观呈圆形或类圆形，平均粒径、Zeta电位、包封率和载药量分别为（202.62±1.52）nm、（0.17±0.12）mV、（58.20±2.43）%和（1.25±0.13）%。体外释放实验表明，纳米粒体外释放t_1/2为1.1h，在10.0h累积释放率达到74.0%。结论壳聚糖修饰对纳米粒的粒径及Zeta电位影响较大；制备的纳米粒包封率较高，粒径小，体外释放具有一定缓释特征。

Preparation and Evaluation of Triptolide-Loaded Chitosan/PEG-PLA Nanoparticles

OBJECTIVE To prepare triptolide-loaded chitosan/polyethylene glycol-polylactic acid (PEG-PLA) nanoparticles and to evaluate their quality. METHODS Low molecular weight chitosan was obtained by degradation reaction, and the viscosity-average molecular weight and degree of deacetylation were determined by viscometry and acid-base titration method, respectively. The PEG-PLA nanoparticles were prepared by emulsification solvent evaporation method with chitosan as modifying agent. Then, the influence of modification of chitosan on the nanoparticles was investigated. The morphological characteristics, particle size, Zeta potential, encapsulation efficiency, drug loading and release in vitro of the prepared nanoparticles were evaluated. RESULTS The viscosity-average molecular weight and degree of deacetylation of chitosan were 20 000 and 90%, respectively. The particle size and Zeta potential of the nanoparticles increased after the modification of chitosan, while the encapsulation efficiency was almost the same. The shape of the prepared nanoparticles was spherical, and the mean particle size, Zeta potential, encapsulation efficiency and drug loading were (202.62?1.52) nm, (0.17?0.12) mV, (58.20?2.43)% and (1.25 ?0.13)%, respectively. The release profiles showed that the accumulated release rate of the nanoparticles was 50.0% at 1.1 h and reached 74.0% at 10.0 h. CONCLUSION Chitosan modification can affect the particle size and Zeta potential. The nanoparticles show a certain sustained release characteristics with well-distributed particle size as well as high entrapment efficiency.