Synthesis and characterization of β-cyclodextrin/fraxinellone inclusion complex and its influence on interaction with human serum albumin

Aqueous solubility is one of the key determinants in developing new chemical entities as drugs. In this study, to improve the solubility of fraxinellone, a novel β-cyclodextrin/fraxinellone inclusion complex was prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and elemental analysis. Moreover, the influence of inclusion of small molecule by cyclodextrins on its binding with transporter in human body is essential for drug development. For the first time, we report the interaction of fraxinellone and its inclusion complex with human serum albumin. Fluorescence quenching of albumin by fraxinellone and its inclusion complex is a static process through complex formation. The results indicated that β-cyclodextrin did not affect the binding force and site of fraxinellone to the protein. Furthermore, circular dichroism showed that both fraxinellone and its inclusion complex induced a significant change in the secondary structure of human serum albumin.