2,4-D/CMC接枝物纳米粒子的制备与缓释性能研究

以羧甲基纤维素钠（CMC）为基材,甲基丙烯酸甲酯（MMA）和二甲基二烯丙基氯化铵（DMDAAC）为改性单体,通过乳液聚合制备了CMC-g-P(MMA-DMDAAC)共聚物,采用自组装方法负载2,4-二氯苯氧乙酸（2,4-D）得到2,4-D/CMC-g-P(MMA-DMDAAC)纳米药物缓释体系。利用傅里叶红外光谱（FTIR）、差示扫描量热法（DSC）、热重分析（TGA）、扫描电镜（SEM）、粒度分析仪对其结构和形貌进行表征,并探究其载药性能和缓释性能。结果表明,2,4-D/CMC-g-P(MMA-DMDAAC)载药粒子呈笼状结构,粒度分布为160～425 nm;其载药率随着CMC∶MMA∶DMDAAC的摩尔比增大而提高,最高可达40.8%;其药物累计释放率随CMC∶MMA∶DMDAAC的摩尔比增大而降低,其释放行为符合Weibull模型,遵循Fick扩散机理。

Preparation and sustained release performance of 2,4-D/grafted CMC nanoparticles

CMC-g-P(MMA-DMDAAC) was prepared by emulsion copolymerization and trapping as well as encapsulation of 2,4-D via self-assembly resulted in the formation of 2,4-D/CMC-g-PDMDAAC nanoparticles. Its structure and morphology were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron (SEM) and dynamic light scattering (DLS). Furthermore, the encapsulation efficiency and sustained-release characteristics were investigated. The results demonstrated that the 2,4-D/CMC-g-P(MMA-DMDAAC) drug-loaded particles showed a cage structure with a particle size distribution from 160 nm to 425 nm. Moreover, the encapsulation efficiency increased as the molar ratio of monomers increased, which could reach up to 40.8%. In addition, the higher molar ratio of the monomers was, the lower cumulative release rate of the drug exhibited. Overall, the mechanism of release of 2,4-D from nanocarriers was consistent with Fickian behavior.