巯基化壳聚糖修饰的PLA-PCL-TPGS纳米粒用于肺癌口服化疗药物载体的研究

Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles as oral drug carrier for lung cancer chemotherapy

目的 构建一种新型的巯基化壳聚糖修饰的聚乳酸-聚己内酯-聚乙二醇1000维生素E琥珀酸酯（PLA-PCL-TPGS）纳米粒,探讨其用作肺癌口服化疗药物载体的可行性.方法 合成PLA-PCL-TPGS无规共聚物并进行表征,再以商业化的PCL和PLA-PCL-TPGS无规共聚物制备3种用于口服递送紫杉醇的纳米载体：5％巯基化壳聚糖修饰的PCL纳米粒（CNP）、未修饰的PLA-PCL-TPGS纳米粒（UNP）和5％巯基化壳聚糖修饰的PLA-PCL-TPGS纳米粒（TNP）,并对其粒径、Zeta电位、表面形态、载药量和包封率进行表征,研究其体外药物释放行为、体外人肺癌细胞A549的摄取及对A549细胞的毒性,采用离体肠吸收实验测定跨肠道屏障转运的紫杉醇含量.结果 成功合成了PLA-PCL-TPGS无规共聚物.场发射扫描电镜结果表明,3种载紫杉醇的纳米粒均呈球状,粒径约200 nm.PLA-PCL-TPGS纳米粒经巯基化壳聚糖修饰后,表面由负电荷转为正电荷.UNP和TNP的载药量、包封率和32 d内的紫杉醇累积释放率均高于CNP,差异均具有统计学意义（均P＜0.05）.A549细胞对TNP的摄取率显著高于CNP和UNP,差异均具有统计学意义（均P＜0.05）.体外细胞毒性研究结果显示,TNP较临床应用的紫杉醇注射液对A549细胞具有更强的细胞毒性.离体肠吸收实验结果显示,TNP可通过开放紧密连接、绕过P-糖蛋白外排泵增加紫杉醇的运输.结论 PLA-PCL-TPGS纳米粒经巯基化壳聚糖修饰后能增强细胞摄取和细胞毒性,有望用作肺癌口服化疗药物载体.

Objective To construct a novel thiolated chitosan modified poly（lactide-co-ε-caprolactone）-d-α-tocopheryl polyethylene glycol 1 000 succinate （PLA-PCL-TPGS） nanoparticle,and investigate the feasibility of its use as an oral carrier for lung cancer chemotherapy.Methods The PLA-PCL-TPGS random copolymer was synthesized and characterized.Then three types of nanoparticles from commercial PCL and PLA-PCL-TPGS random copolymer were prepared for oral carrier of paclitaxel,including 5% thiolated chitosan-modified PCL nanoparticles （CNPs）,unmodified PLA-PCL-TPGS nanoparticles （UNPs）,and 5% thiolated chitosan-modified PLA-PCL-TPGS nanoparticles （TNPs）.The prepared nanoparticles were characterized in terms of size,Zeta potential,morphology,drug loading and encapsulation efficiency.The in vitro drug release profiles and cellular uptake of the nanoparticles by human lung cancer cell lines A549 cells were investigated,and cytotoxicity against A549 cells was also evaluated.The evened sac method was used for the measurement of transportation of paclitaxel across the intestine barrier.Results The field emission scanning electron microscopy results showed that the three types of paclitaxel-loaded nanoparticles were spherical with a diameter about 200 nm.The surface charge of PLA-PCL-TPGS nanoparticles was reversed from negative to positive charge after thiolated chitosan modification.The UNPs and TNPs achieved higher drug loading,encapsulation efficiency and drug release after 32 d than CNP （all P〈0.05）.The TNPs had significantly higher cell uptake efficiency than that of CNPs and UNPs （all P〈0.05）.In vitro cell viability studies showed advantages of TNPs over a clinically available paclitaxel injection in terms of cytotoxicity against A549 cells.Ex vivo absorption studies revealed that the TNPs can increase paclitaxel transport by opening tight junctions and bypassing the efflux pump of P-glycoprotein.Conclusion PLA-PCL-TPGS nanoparticles modified by thiolated chitosan can enhance the cellular uptake and cytotoxicity,which reveals a potential application for oral chemotherapy of lung cancer.