中药多效组合聚合物胶束口服递药系统的构建及其作用机制

Oral drug delivery for insoluble ingredients of Chinese medicine is the favor part in pharmaceutics of Chinese medicine research, drug delivery mechanism is different, but the biological adhesion, P-gp inhibition, CYP450 inhibition in the same delivery system in the collaborative promote oral absorption is not clear. Previous study found that bio-adhesive nanoparticles, P-gp inhibitors, CYP450 inhibitors are able to promote the oral absorption. Therefore, assumes the use of biological adhesion type material, the integration of P-gp inhibitor, CYP450 inhibitor to the biological adhesion type material accelerate synergistically oral absorption. The project intends to use paclitaxel as a model drug, employ polymeric micelles as drug delivery system, select the TPGS modified chitosan copolymer as material, using gallic acid(GA) synthesis or adsorption of modified TPGS- chitosan copolymer, GA-TPGS- chitosan and jointly build a paclitaxel loaded polymer micelle, as paclitaxel oral drug delivery system, hope through a variety of mechanisms of coordination to promote its oral absorption, at the same time, GA also increase synergistically anticancer effect of paclitaxel. To improve mechanism of oral drug delivery system with multi combination design to improve synergistically oral absorption, and to improve the constructing mode of delivery drug system for traditional Chinese medicine composition used as the medicine functional group and the efficacy of synergistic substance. The arm is to provide new ideas for constructing of new delivery system for the component of Chinese traditional medicine.

难溶性中药成分口服递药是中药药剂学研究的热点，递药机制各不相同，但将生物黏附、P-gp抑制、CYP450抑制在同一递药系统中协同促进口服吸收尚不清楚。前期研究发现生物黏附纳米粒、P-gp抑制剂、CYP450抑制剂等均能促进口服吸收，因此，设想采用生物黏附型材料，将P-gp抑制剂、CYP450抑制剂整合到生物黏附型材料中，协同促进口服吸收。本项目拟以紫杉醇为模型药物，以聚合物胶束作为递药系统，选择TPGS修饰壳聚糖共聚物为材料，以没食子酸（GA）合成或吸附方式修饰TPGS-壳聚糖共聚物，共同构建载紫杉醇的GA-TPGS-壳聚糖聚合物胶束，作为紫杉醇口服递药系统，希望通过多种机制协同促进其口服吸收，同时GA还能协同紫杉醇的抗癌作用,探讨多重组合设计口服给药递药系统协同提高口服吸收的机制，以及中药成分作为递药功能基与药效增效物质双重功能给药系统的构建模式，为中药成分组合新型递药构建提供新的思路.

以没食子酸甲酯、壳聚糖（CS）、聚乙二醇1000维生素E琥珀酸酯（TPGS）为原料，合成生物黏附性两亲共聚物没食子酸-壳聚糖-TPGS（GA-CS-TPGS），并以紫杉醇（Paclitaxel, PTX）为模型药物，构建GA-CS-TPGS /PTX载药胶束，以期获得一种良好的难溶性药物口服载体，改善紫杉醇的口服生物利用度。将没食子酸甲酯接枝于CS分子上，得到没食子酸壳聚糖（GA-CS）；以琥珀酸酐（SA）和4-二甲氨基吡啶（DMAP）对TPGS进行端羟基羧基化，再在1-乙基-（3-二甲氨丙基）碳二亚胺盐酸盐（EDC•HCL）和N-羟基琥珀酰亚胺（NHS）的缩合作用下使羧基反应活性增强；通过与GA-CS中CS的自由氨基发生酰胺化反应而接枝，制备出一种GA-CS-TPGS共聚物，采用红外光谱仪和核磁共振波谱仪对产物进行表征。以紫杉醇为模型药物，采用超声乳化法制备载药聚合物胶束（GA-CS-TPGS /PTX）；采用高效液相色谱仪考察了聚合物胶束的包封率和载药量；芘荧光探针光谱法测定共聚物的临界胶束浓度（CMC）；动态光散射法（LS）测量聚合物胶束的粒径和Zeta电位；透射电子显微镜（TEM）观察胶束的形貌；X射线衍射仪（XRD）考察药物在胶束中的包载情况。以SD大鼠为动物实验对象，灌胃给药，尾静脉取血，考察GA-CS-TPGS /PTX胶束与紫杉醇参比制剂在大鼠体内的药物动力学特征。考察了GA-CS-TPGS生物粘附性及细胞水平递药机制、对CYP3A酶的抑制作用及对人肺癌细胞A549的抗肿瘤作用。结果表明，GA和TPGS成功地接枝到CS上。采用超声乳化法制备的胶束形态和稳定性良好，包封率为80%，载药量为8.2%，胶束粒径约为134.9 nm，PDI为0.172，Zeta电位为34.8 mV，CMC值为0.0156 mg/mL，胶束在透射电镜观察下，大小比较均匀，无粘连。XRD结果显示，紫杉醇以无定形形式位于聚合物胶束中。由药代动力学结果可知，GA-CS-TPGS/PTX胶束胶束与参比制剂相比，生物利用度提高了4倍。在体肠试验表明载药聚合物胶束能使吸收常数增加，各种蛋白介导了胶束溶液的内吞过程。本品对CYP3A酶和人肺癌A549有一定的抑制作用。本项目成功合成了GA-CS-TPGS共聚物，超声乳化法制备的载药胶束性状良好，相比紫杉醇参比制剂，提高了药物口服生物利用度。