基于“药辅共济”的大黄酸偶联物复合口服吸收促进剂的构建与评价

Paclitaxel, a anti-tumor Chinese medicine effective component, due to its poor solubility in water, poor permeability and P-glycoprotein(P-gp) excretion in intestinal tract, has serious problems for oral administration. It can cause multi-drug resistance phenomenon after long-term use. Functional amphiphilic polymer which designed for the problems will solve these problems effectively. We have synthesized Rhein-carboxymethyl chitosan conjugate with carboxymethyl chitosan and rhein which is a Chinese medicine effective component with anti-tumor effect, reversing multi-drug resistant effect, decreasing the intestinal mucosa damage effect, and synergy with paclitaxel. The project will design the complex oral absorption enhancers with Rhein-carboxymethyl chitosan conjugate and tocopheryl polyethylene glycol 1000 succinate (TPGS) with P-gp inhibition effect based on the study we have completed. By the pharmacological effect and delivery action of micelles form by the complex oral absorption enhancers, the complex oral absorption enhancers can increase the solubility in water and permeability of paclitaxel, decrease the intestinal mucosa damage, improve oral absorption bioavailability of paclitaxel, enhance the effective delivery of paclitaxel in the body, and decrease multi-drug resistance effect. So the complex oral absorption enhancers can increase antitumor effect and decrease toxicity of paclitaxel. The anti-tumor synergistic therapeutic action will come into being in this project according to the idea of " Combination Therapy with Drugs and Excipients ". Meanwhile, the project will also evaluate the effect of the complex oral absorption enhancers by Caco-2 cells model，MCF-7/ADR cells model and zebrafish model at the cellular and biological level. The project will provide a new idea and method for the study of antitumor preparations from the point of view of functional excipients.

中药抗肿瘤有效成分紫杉醇由于水溶性差、渗透性差及肠道P-糖蛋白（P-gp）外排等原因口服给药存在严重问题，且长期使用存在多药耐药现象。功能型两亲性高分子聚合物能有效解决这些问题。我们已将具有抗肿瘤、逆转多药耐药、保护肠粘膜、与紫杉醇协同作用的中药有效成分大黄酸偶联于羧甲基壳聚糖上,形成大黄酸-羧甲基壳聚糖偶联物。本项目拟在此基础上，将其与具有P-gp抑制作用的维生素E聚乙二醇1000琥珀酸酯（TPGS）复合，构建复合口服吸收促进剂。通过构成材料的药理作用及其形成的胶束的传递作用，该复合口服吸收促进剂能增加紫杉醇溶解性、渗透性，减少胃肠道刺激，提高口服吸收利用度，加强紫杉醇在体内的有效传递，减少多药耐药现象的发生，增效减毒，达到“药辅共济”协同抗肿瘤的效果。并通过Caco-2细胞、MCF-7/ADR细胞及斑马鱼模型对其进行评价。本项目将从功能型辅料的角度为抗肿瘤制剂研究提供新思路和新方法。

中药抗肿瘤有效成分紫杉醇（PTX）由于水溶性差、渗透性差及肠道P-糖蛋白（P-gp）外排等原因口服给药存在严重问题，且长期使用存在多药耐药现象。本项目用TPGS与大黄酸-羧甲基壳聚糖偶联物（CR偶联物）复合成为一种口服吸收促进剂——TPGS-CR偶联物，利用TPGS的P-gp抑制作用；大黄酸的抗肿瘤、逆转多药耐药、与紫杉醇协同作用；羧甲基壳聚糖的口服促进收作用，使TPGS-CR偶联物形成的胶束不仅能够促进抗肿瘤药物紫杉醇的口服吸收，并且协同紫杉醇，对其起到增效减毒的作用。本项目已完成了TPGS-CR偶联物的合成，通过IR、1HNMR、CMC值、取代度对其进行了表征，对载紫杉醇的TPGS-CR偶联物胶束（PTX/TPGS-CR胶束）的载药工艺进行了优化，并用DLS、TEM、DSC等进行了表征，其载药量为（48.20±3.03）%、包封率为（87.26±4.91）%、粒径为（197.3±4.4）nm，PDI为0.131±0.021，电位为（-31.8±0.5）mV，为近球形。大鼠在体肠吸收实验、大鼠药动学实验、荷瘤小鼠的药效学实验表明TPGS-CR偶联物具有很好的口服促吸收作用并且安全性高，PTX/TPGS-CR胶束显著提高了紫杉醇的口服生物利用度。Caco-2细胞的细胞毒实验表明TPGS-CR偶联物安全性好，PTX/TPGS-CR胶束对肿瘤细胞的增殖抑制作用具有时间和浓度依赖性。MCF-7细胞及耐药MCF-7细胞实验表明，PTX/TPGS-CR胶束对耐药细胞的杀伤作用优于市售紫杉醇制剂Taxol®。斑马鱼模型的抑瘤实验结果表明，PTX/TPGS-CR胶束的抑瘤作用好；TPGS-CR偶联物安全性好；其可以在一定程度上增加斑马鱼对P-gp底物的摄取；Western-blot实验表明TPGS-CR偶联物对P-gp表达有一定的下调作用；RT-PCR实验检测TPGS-CR偶联物对斑马鱼胚胎P-gp蛋白表达基因有一定的下调作用，从而进一步解释了TPGS-CR偶联物协同紫杉醇抗肿瘤的机制。综上，TPGS-CR偶联物能够促进紫杉醇的口服吸收，其协同紫杉醇抗肿瘤的机制与协同抑制肿瘤细胞增殖、下调P-gp以克服药物外排及耐药等相关。该项目研发的口服吸收促进剂对紫杉醇的口服递送并提高其抗肿瘤效果具有一定意义。