Characterization and stability of beta-acids/hydroxypropyl-β-cyclodextrin inclusion complex

The inclusion complex (IC) of beta-acids/hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was prepared by the co-grinding method to improve the solubility and stability of beta-acids. Formation of inclusion complexes was characterized by ultraviolet/visible (UV-Vis) spectroscopy, fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffractometry (XRD) and nuclear magnetic resonance (H-1 NMR). The effects of temperature, light, and pH on the stability of the ICs as well as ICs solubility were also explored. Results showed that beta-acids/ hydroxypropyl-beta-cyclodextrin (HP-beta-CD) ICs formed successfully. Water solubility of beta-acids increased (up to 1.73 mg/mL) after forming an IC with HP-beta-CD. Additionally, the inclusion complexes showed increased photostability, thermostability, and pH stability. At different light conditions and pH condition, the preservation rate of beta-acids was able to reach above 70% as well as the temperature is lower than 60 degrees C. This study proved that IC of beta-acids/HP-beta-CD could apply in water system. (C) 2019 Elsevier B.V. All rights reserved.