彗星状载羟基喜树碱双嵌段共聚物的制备与质量评价

Preparation and quality evaluation of comet-shaped hydroxy camptothecin-loaded amphiphilic block copolymer

本文以可降解聚合物单甲氧基聚乙二醇-聚乳酸聚乙醇酸(Me PEG-PLGA)为载体,羟基喜树碱(HCPT)为模型药物,利用SPG(Shirasu porous glass membrane)模板法,通过正交设计优化制备了彗星状MePEG-PLGA-HCPT共聚物粒子。采用动态光散射分析、扫描/透射电镜、X-射线衍射法和差示扫描量热法等研究载药粒子的粒径、zeta电位、载药量、收率、形态和HCPT的存在状态;初步评价了载药粒子的体外释药;MTT法初步考察对肝癌BEL-7402细胞的毒性作用。结果显示,最佳制备条件为:HCPT与MePEG-PLGA的质量比为1∶1,氮气压力为100 k Pa,SPG膜孔径为1.1μm;载药粒子在电镜下呈彗星状,其中头部螺旋成束,尾部为散开的纳米束;粒子的载药量可达到46.2%,收率为96.4%,zeta电位为-31.4 m V;HCPT以无定形态均匀分布于MePEG-PLGA粒子中,具有药物缓释的优点,且药物释放的速度随着载药量的增加而增大;该形貌的载药粒子相对于球形载药粒子对肝癌BEL-7402细胞的抑制作用更强,有用于肿瘤临床治疗的潜能。

In this study, we used Shirasu porous glass membrane（SPG） as a template and hydroxy camptothecin（HCPT） as a model drug to prepare the comet-shaped Me PEG [methoxyl poly（ethylene glycol）]- PLGA [poly（lactic-co-glycolic acid）-HCPT amphiphilic block copolymer. Our method was optimized by the orthogonal design method. The partical size, zeta potential, drug-loaded content, yield, shape and status of the obtained comet-shaped Me PEG-PLGA-HCPT particles were further characterized by dynamic light scattering（DLS）, scanning electron microscopy（SEM）/transmission electron microscopy（TEM）, X-ray diffraction（XRD） and differential scanning calorimetry（DSC） et al, respectively. In vitro release was preliminary evaluated. MTT assay to preliminary evaluate the cytotoxicity of particles against human liver BEL-7402 cells. Based on these experimental results, the optimal preparation conditions contain： weight ratio of HCPT to Me PEG-PLGA was 1∶1, nitrogen pressure was 100 k Pa and SPG membrane pore size was 1.1 μm. The particles exhibited a comet-shaped shape, fairly uniform size and were well dispersed. The drug-loading content was 46.2%, with yield of 96.4%, and zeta-31.4 m V. The distribution of HCPT in particles was very uniform, and HCPT showed a amorphous state existed in particles. The release behavior in vitro showed sustained releasing, and with the drug loading content in proportion to the release of the drug. MTT test indicated that the HCPT-loaded comet-shaped particles had enhanced the cytotoxicity against human liver BEL-7402 cells relatively to the HCPT-loaded spherical particles in vitro. The results showed a promising potential application of the preparation in clinical treatment of tumor.