[关键词]
[摘要]
目的 制备长春胺(VIN)与羟丙基-β-环糊精(HP-β-CD)的包合物(VIN/HP-β-CD),并对包合物进行表征和性能测定,采用量化计算与分子模拟方法从理论角度研究其包合机制。方法 通过饱和溶液法制备VIN/HP-β-CD;以包合物的载药量为指标,选用正交试验筛选VIN/HP-β-CD包合物制备处方与工艺;运用紫外-可见光谱滴定法研究VIN与HP-β-CD之间的包合行为,用Job曲线法确定其包合比。采用扫描电镜(SEM)、X射线粉末衍射(XRD)、红外吸收光谱(IR)、热分析技术(TG、DSC)和核磁共振(1H-、2D-NMR)对VIN/HP-β-CD包合物进行表征。测定VIN/HP-β-CD包合物的水溶性,并在模拟人体胃液和肠液环境下测试包合物稳定性,进一步采用理论计算研究VIN/HP-β-CD超分子体系的形成机制。结果 采用饱和溶液法制备该包合物的最优条件为投料比VIN与HP-β-CD 1:1,包合温度40℃,包合时间为7 h,甲醇与水的体积比为1:6作为溶剂。包合物的包合比为1:1,VIN与HP-β-CD形成包合物后,其水溶性从原来的0.04 mg/mL提高到了16.5 mg/mL,VIN的热分解温度从240.5℃提高到了306.1℃。1H-NMR与NOESY谱表明包合物是VIN的a环从HP-β-CD的大口端进入而形成的,量化计算与分子对接表明最优包合模式与核磁共振研究结果一致;分子动力学模拟研究表明,在水环境中VIN能深入HP-β-CD的疏水空腔,主-客体之间的相互作用加强,空间尺寸匹配较好。结论 VIN与HP-β-CD形成包合物后,水溶性和热稳定性得到显著提高,疏水作用、氢键作用和范德华力为包合物形成的主要驱动力。
[Key word]
[Abstract]
Objective The inclusion complex of vincamine (VIN) and hydroxypropyl-β-cyclodextrin (HP-β-CD) was prepared and characterized. Molecular simulation method was used to study the formation mechanism of inclusion complex. Methods The inclusion complex of VIN/HP-β-CD was prepared by saturated solution. The preparation technology of VIN/HP-β-CD inclusion complex was optimized by orthogonal design, and taking the drug-loading of the inclusion compound as the index. The stability constant of inclusion complex between VIN and HP-β-CD was studied by UV-Vis spectrometry titration, and the inclusion ratio was determined by Job plots method. The VIN/HP-β-CD inclusion complex was characterized by scanning electron microscope (SEM), X-ray powder diffractometry (XRD), infrared spectroscopy (IR), thermal analysis techniques (TG and DSC), and nuclear magnetic resonance (1H, 2D NMR). The water solubility of the VIN/HP-β-CD inclusion complex was measured and the stability test was conducted in the simulated human gastric juice and intestinal fluid environment. Molecular docking and molecular dynamics were used to study the forming mechanism of supramolecular system of VIN/HP-β-CD. Results Using saturated solution method, the optimum conditions of inclusion were:1:1 for molar ratio of VIN and HP-β-CD, 40℃ for inclusion temperature, 7 h for inclusion time and volume ratio of methanol to water (1:6) as solvent; Job curve and UV-vis spectroscopy showed that inclusion ratio of host-guest inclusion complexes was 1:1; After VIN formed inclusion complexes with HP-β-CD, its solubility increased from 0.04 mg/mL to 16.5 mg/mL, and the thermal decomposition temperature of VIN increased from 240.5℃ to 306.1℃. 1H-NMR and NOESY spectra indicated that the inclusion complex was formed by the a-ring of VIN entering from the large end of HP-β-CD. Quantum chemical calculation and molecular docking indicated that the optimal inclusion mode was consistent with the results of NMR studies. Molecular dynamics studies showed that VIN can penetrate into the hydrophobic cavity of HP-β-CD in water environment, and the interaction between host and guest was strengthened. The space size of host-guest matched better. Conclusion The solubility and thermal stability were significantly improved after the formation of inclusion complex with VIN and HP-β-CD. Hydrophobicity, hydrogen bonding, and van der Waals forces were the main driving forces for inclusion complex formation.
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[基金项目]
国家自然科学基金资助项目(21762051);国家自然科学基金资助项目(21562048);云南省高校科技创新团队支持计划资助;云南民族大学研究生创新项目(2018YJCXS245)