N-辛基-N-季铵化壳聚糖/CMCNa复合胶束的制备、表征及安全性评价

Preparation,characterization and safety evaluation for N-octyl-N-quaternary ammonium chitosan/CMCNa composite micelles

制备N-辛基-N-季铵化壳聚糖(NTMC)胶束,并用羧甲基纤维素钠(CMCNa)对胶束进行包覆以获得安全、稳定的复合胶束制剂。由辛基化和季铵化反应合成NTMC,并考察其临界胶束浓度;通过超声-透析法制备NTMC胶束,测定胶束的包封率和载药率;使用CMCNa对NTMC胶束进行包覆,考察包覆前后胶束的形态、粒径、Zeta电位以及细胞毒性和溶血性的变化。所制得的NTMC的辛基取代度为(37.5±3.6)%,季铵基取代度为48.4%,具有较低的临界胶束浓度(35.6μg/mL)。NTMC胶束粒子呈球形,粒径为(224.6±8.4)nm,Zeta电位为+(44.7±4.5)mV,对紫杉醇的载药率高达(40.2±2.2)%,包封率为(34.4±1.7)%。NTMC/CMCNa复合胶束粒子较不规则,略呈球形,粒径为(302.4±27.3)nm,Zeta电位为-(37.4±6.2)mV。与NTMC胶束相比,NTMC/CMCNa复合胶束的细胞毒性及溶血性大大降低。结果表明:NTMC胶束对难溶性药物(如紫杉醇)有很好的增溶效果,通过CMCNa包覆,可以屏蔽NTMC胶束的强烈正电荷,显著提高制剂的安全性。

The aims of this study were to obtain a safe and stable composite micelle using N-octyl-N-quaternary ammonium chitosan （NTMC） coating with sodium carboxymethyl cellulose （ CMCNa）. NTMC was synthesized and its critical micelle concentration was measured. NTMC micelles were prepared by ultrasonic dialysis; its drug loading efficiency and drug encapsulation efficiency were determined by HPLC. The composite micelle NTMC/ CMCNa was prepared by absorption of CMCNa on the NTMC micelles. The effects of CMCNa-coating on morphology, particle size, Zeta potential, cytotoxicity and hemolysis of micelles were studied. It was found that NTMC with （37.5 ± 3.6） % N-octyl substitution and 48.4% N-trimethyl substitution exhibited a low critical micelle concentration at 35.6 μg/mL. The particle size of NTMC micelles was （224.6 ± 8.4） nm, Zeta potential was ＋ （44.7 ±4.5） mV and a spherical shape was observed under AFM. The drug loading efficiency of NTMC micelles to paclitaxel was up to （40.2 ± 2.2 ） %, with the drug encapsulation efficiency of （ 34.4 ± 1.7 ） %. The particle size of NTMC/CMCNa micelles was （302.4 ± 27.3） nm, the Zeta potential was -（37.4 ± 6.2） mV and they showed a slightly irregular spherical shape. Compared with NTMC micelles, NTMC/CMCNa micelles exhibited a decreased cytotoxicity and hemolysis. In conclusions, NTMC micelles exhibited the significant solubilizing effect for insoluble drugs, such as paclitaxel. By the coating of CMCNa, the strong positive charge of NTMC micelles can be shieled to improve the safety of the micelles.