负载紫杉醇壳聚糖纳米粒的制备、表征与释药性能

背景：紫杉醇是一种天然抗肿瘤药物,但其水溶性极低。壳聚糖经接枝改性，生成的共聚物可在液相中生成纳米粒，可用于药物的缓释和控释。 目的：对制备的负载紫杉醇的壳聚糖纳米粒进行表征，分析其体外药物释放能力。 设计、时间及地点：重复测量设计，于2008-01/07在华北煤炭医学院医学系实验室完成。 材料：壳聚糖，平均相对分子质量为2.0×105，脱乙酰度为92%，为浙江省玉环海洋生物化学有限公司产品。紫杉醇，批号082329802，为中国药品生物制品检定所产品。 方法：采用引发接枝效率高、引发反应条件温和的二羟基二过碘酸合镍钾为引发剂，在壳聚糖上接枝醋酸乙烯酯，该聚合物在水溶液中直接生成具有疏水核心、亲水表面的纳米粒，即壳聚糖纳米粒，再利用超声振荡技术将0.5~5.0 mg紫杉醇与上述纳米粒混合制成负载紫杉醇的壳聚糖纳米粒。 主要观察指标：激光粒度分析仪测定纳米颗粒的粒径大小、粒径分布及Zeta电位，透射电镜观察纳米颗粒的外观形态，高效液相色谱法分析负载紫杉醇的壳聚糖纳米粒的包封率、载药量和释药性能。 结果：壳聚糖纳米粒和负载紫杉醇的壳聚糖纳米粒，其粒径分别为196.2 nm和320.8 nm，粒径分布较窄，纳米粒表面均带正电荷，Zeta电位比较差异无显著性意义（F=0.818，F=3.38，P均>0.05）。稳定的纳米粒呈球形，粒径均匀。紫杉醇的加入量可影响纳米粒的包封率，紫杉醇的加入量为纳米粒的量2%时，达到最大包封率93.6%。体外模拟释药结果表明药物释放曲线分为两个阶段，突释阶段微球释药量在24 h内达48.3%，缓释阶段微球释药持续时间长，在175 h时释药量达75.9%，载药纳米粒的药物释放速率持续稳定。 结论：接枝共聚法制备壳聚糖纳米粒简便可靠，负载紫杉醇后纳米粒径明显变大，表面带有正电荷，且纳米粒对紫杉醇有很高的包封率，体外释药具有明显的缓释作用。

Preparation, characterization and drug release property of paclitaxel nanoparticles

BACKGROUND: Paclitaxel is a natural anticancer drug, which has demonstrated significant activity in clinical trials. However, it has been limited due to poor aqueous solubility. Chitosan can be modified into graft copolymer, which changed into nanoparticles in aqueous solution, and employed as controlled release carriers for drugs. OBJECTIVE: To study the characterization, in addition, to evaluate in vitro drug release ability of paclitaxel nanoparticles. DESIGN, TIME AND SETTING: A repeated measurement design was conducted at the Laboratory of North China Coal Medical University from January 2008 to July 2008. MATERIALS: The average molecular weight of 2.0×105 chitosan with 92% deacetylation degree was produced by Golden-shell Biochemical Co., Ltd. Paclitaxel (lot number: 082329802) was provided by National Institute for the Control of Pharmaceutical and Biological Products. METHODS: The potassium diperiodaton-ickelate served as initiator, chitosan-graft-vinyl acetate copolymers were synthesized by free radical graft copolymerization, which could be directly transformed into nanoparticles with hydrophobic core and hydrophilic surface in the water medium. Paclitaxel nanoparticles were prepared via mixture 0.5-5.0 mg paclitaxel with nanoparticles by ultrasonic irradiation technology. MAIN OUTCOME MEASURES: Particles size, polydispersity index zeta potential was detected by laser particle size analyzer. The morphology of chitosan nanoparticles and paclitaxel nanoparticles was observed by transmission electron microscope. In addition, encapsulation capability, loading content and in vitro drug release of the paclitaxel nanoparticles was analyzed by high-performance liquid chromatography. RESULTS: The mean diameters of chitosan nanoparticles and paclitaxel nanoparticles were 196.2 nm and 320.8 nm, respectively. The nanoparticles possessed a uniform particles size distribution and an obvious positive charge surface, but the Zeta potential had no significant difference (F=0.818, F =3.38, all P > 0.05). The dose of paclitaxel could affect the encapsulation rate, which could up to 93.6% when added the quantity of paclitaxel was 2% of anoparticles. The results of simulate drug release showed that drug release was reach 48.3% in 24 hours at the burst release phase, which up to 75.9% at 175 hours longer in the slower release phase. The encapsulation rate of drug-loaded nanoparticles was stable. CONCLUSION: The preparation method is reliable and simple. The nanoparticles possessed good physical performance and sustained release character in vitro.