双硫仑-羟丙基-β-环糊精包合常数测定与包合物形成的热力学性质考察

Studies on equilibrium constants of DSF-β-CD_(HP) inclusion complexes and thermodynamic properties

目的测定双硫仑羟丙基β环糊精(DSFβCDHP)的包合常数;研究包合物形成的热力学性质。方法采用RP HPLC法。测定溶液中双硫仑含量,由测定结果计算各浓度的βCDHP溶液中双硫仑的溶解度,以双硫仑溶解度对βCDHP浓度作图,得到相溶解度图;测定不同色谱条件下双硫仑羟丙基β环糊精的保留时间,根据保留时间计算稳定常数及不同温度下的包合常数K。结果当羟丙基β环糊精浓度较低时,可形成1∶1包合物;30℃时DSFβCDHP的包合常数为1 624.41 L.mol-1;其包合反应的焓变(ΔH)为-25.25 kJ.mol-1,吉布斯自由能(ΔG)和熵变(ΔS)分别为-12.60 kJ.mol-1与-41.74 J.mol-1K-1。结论双硫仑与羟丙基β环糊精的包合作用为一放热过程,是分子间氢键和范德华力作用的结果;采用较低的温度有利于双硫仑完全形成包合物。

Objective To study the thermodynamic properties of disulfiram-hydroxypropyl-β-cyclodextrin （DSF-β-CDHP） inclusion complexes and determine the equilibrium constants of the inclusion complex. Methods The reverse-phase high performance liquid chromatogram was employed to determine the retention times of DSF-β-CDm, under different conditions, then the equilibrium constants and thermodynamic parameters were calculated. Results The inclusion complexes containing equimolar disulfiram（DSF） and hydroxypropyl-β-cyclodextrin（β-CDHP） were formed when the concentration of β-CDup was low. The equilibrium constant of inclusion complexes was confirmed to be 1624.41 L· mol^-1 at 30 12 through the way of RP-HPLC. The changes of enthalpy（△H^0）, Gibbs＇ free energy（△G^0） and entropy （△S^0）of the system during the formation of DSF-β-CDHP were - 25.25 kJ·mol^- 1, - 12.60 kJ·mol^- 1 and - 41.74 J· mol^- 1· K^- 1 respectively. Conclusions The negative free energy change of this reaction demonstrate the spontaneous formation of DSF-β-CDHp, which caused by the intermolecular hydrogen bond and Van der Waals forces. The low temperature is useful for the formation of inclusion complexes.