Preparation and Characterization of a Complex of Paeonol and Hydroxypropyl-β-cyclodextrin

Purpose: To improve the solubility of paeonol in water by complexing with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and also to characterize the physicochemical properties of the complex. Methods: The complex of paeonol and HP-beta-CD was prepared by freeze-drying method. Its physicochemical properties were studied by phase-solubility method, ultraviolet-visible spectrometry (UV), infrared spectrometry (IR), scanning electron microscopy (SEM), x-ray diffractometry (XRD) and thermogravimetric/differential scanning calorimetry (TG/DSC). Results: The phase-solubility results showed that paeonol formed a 1:1 stoichiometric complex with HP-beta-CD while UV and IR spectra suggested that HP-beta-CD and paeonol in the complex interacted by a non-covalent bond. SEM and XRD indicate that the heat stability of paeonol was significantly improved by complexing with HP-beta-CD. Conclusion: Paeonol can be efficiently complexed with HP-beta-CD to form a complex by freeze-drying method. The aqueous solubility and heat stability of paeonol is significantly improved by complexation HP-beta-CD.