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[摘要]
目的研究人参皂苷Rh2与羟丙基-β-环糊精在水溶液中形成的包合物的鉴定及包合过程中的热力学参数变化。方法分别采用薄层色谱法、差热扫描法、红外光谱法和相溶解度法研究人参皂苷Rh2与HP-β-CD的包合产物及包合过程中的热力学参数变化。结果在水溶液中,人参皂苷Rh2与HP-β-CD形成包合物的相溶解度图呈AL-型;人参皂苷Rh2与HP-β-CD在水溶液中的包合过程可自发进行(ΔG<0),且为放热反应(ΔH<0),同时也是熵减过程(ΔS<0)。结论人参皂苷Rh2与HP-β-CD在水溶液中可自发形成包合物,使其溶解度增加近80倍。选择适宜的包合温度将有利于包合过程的进行。
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[Abstract]
Objective To identify the inclusion compound of ginsenoside Rh2 with hydroxylpropyl-β-cyclodextrin (HP-β-CD) in aqueous solution, and to investigate the change of thermodynamic parameters during the inclusion process. Methods The measurements of the inclusion mechanism, inclusion molar ratio of the host and guest molecules, and change of thermodynamic parameters were carried out by the following methods separately; thin layer chromatography (TLC), differential scanning calorimetry (OSC), infrared (IR) spectrometry, phase solubility method, and thermodynamic method, respectively. Results That all the phase solubility diagrams showed a typical AL-type in various temperatures and suggested the formation of a soluble complex of 1∶1 molar ratio. TLC and IR Spectroscopy confirmed that the significant interaction between the host and guest molecules was probably due to the inclusion of aglycone of Rh2 molecule into the hydrophobic cavity of HP-β-CD molecule. The change in the thermodynamic parameters suggested that the inclusion could proceed spontaneously (ΔG<0) along with the release of heat (ΔH<0) and the decrease of entropy (ΔS<0). Conclusion An 1∶1 molar ratio inclusion complex of Rh2 with HP-β-CD could be formed spontaneously and, hence, the solubility of Rh2 in aqueous solution increases to 80 times. Appropriate temperatures probably favor the progress of inclusion procedure.
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