The complex of dapsone with β-cyclodextrin was prepared by the co-precipitation/freeze–drying method. The physical–chemical characteristics of the complex were investigated by different methods and compared with those of the physical mixture and of the isolated compounds. The methods used were infrared spectroscopy, X-ray diffractometry and differential scanning calorimetry. The stability constant was calculated from phase solubility diagram (Higuchi–Connors) and fluorescence spectroscopy. The stoichiometry of the complex was confirmed by Job’s plot. Fluorescence measurements at different temperatures provided the thermodynamic parameters of the complexation. The infrared spectrum showed the disappearance of the SO2 asymmetric stretching band of the drug at 1275 cm−1 after complexation. The amorphization of the samples, as revealed by the X-ray diffraction patterns, was an indirect proof of the inclusion complex. The thermal analysis showed that the curves of the physical mixture are combination of the curves of both constituents (dapsone and β-cyclodextrin) while the absence of the melting peak of the drug in the DSC curve of the complex suggests the inclusion of the drug molecule in the host cavity as a 1:1 complex as indicated by Job’s plot. There was a linear increase in its solubility with the increase of the cyclodextrin concentration and the complex was classified as an AL-type. The value of the stability constant was 3,998 L mol−1 calculated by the Higuchi–Connors diagram and around 18,100 L mol−1 from the fluorescence method indicating a strong interaction between the host and the guest. Complex formation was a spontaneous and enthalpy directed process.
采用共沉淀/冷冻干燥法制备了达索酮与β-
环糊精的复合物。通过不同的方法研究了复合物的物理
化学特征,并与物理混合物和分离化合物的物理
化学特征进行了比较。使用的方法有红外光谱法、X 射线衍射法和差示扫描量热法。根据相溶解度图(Higuchi-Connors)和荧光光谱计算出了稳定常数。约伯图证实了复合物的
化学计量学。不同温度下的荧光测量提供了络合的热力学参数。红外光谱显示,络合后药物在 1275 cm-1 处的 SO2 不对称伸展带消失了。X 射线衍射图谱显示样品发生了非晶化,这间接证明了包合物的存在。热分析表明,物理混合物的曲线是两种成分(达帕松和 β-
环糊精)曲线的组合,而络合物的
DSC 曲线中没有药物的熔化峰,这表明药物分子以 1:1 的络合物形式包含在宿主空腔中,如 Job's plot 所示。随着
环糊精浓度的增加,药物的溶解度呈线性增加,因此该复合物被归类为 AL 型。根据樋口-康诺斯图计算得出的稳定常数为 3,998 L mol-1 ,荧光法计算得出的稳定常数约为 18,100 L mol-1 ,这表明主客体之间存在很强的相互作用。络合物的形成是一个自发的焓定向过程。