β-环糊精对甲硝唑包合作用的热力学研究

摘要

采用Job′s法测定甲硝唑与β-环糊精的包合比，并通过相溶解度法研究不同温度下β-环糊精与甲硝唑的包合常数、增溶倍数和热力学函数。结果表明，甲硝唑与β-环糊精包合比为1∶1，在不同温度下，相溶解度图呈现AL型，而包合常数和增溶倍数均随着温度升高而减小，包合过程的熵变DS、焓变DH及自由能变化DG均为负值，说明包合反应自发进行的放热反应，焓变是包合反应的主要驱动力。%The molar ratio ofmetronidazole withβ-CD were investigated by Job′s method.The thermodynamic parameters and stability constants during the inclusion process were investigated by the phase solubility method at different temperatures.It was suggested that complexation should be formated in solution at 1∶1 molar ratio.The phase diagram was AL type.The stability constants and the solubilities decrease with the temperature increasing.DS,DH,DGwere all of negative value,illustrating the complexation of metronidazole withβ-CD is enthalpy driven which could proceed spontaneously along with the release of heat.