Exploring the formation mechanism of ferulic acid/hydroxypropyl-β-cyclodextrin inclusion complex: spectral analyses and computer simulation

BACKGROUND: The biological functions of ferulic acid (FA) have garnered significant interest but its limited solubility and stability have led to low bioavailability. Hydroxypropyl-beta-cyclodextrin (HP-beta-CD), with its distinctive hollow structure, offers the potential for encapsulating hydrophobic molecules. The formation of an inclusion complex between FA and HP-beta-CD may therefore be a viable approach to address the inherent limitations of FA. To investigate the underlying mechanism of the FA/HP-beta-CD inclusion complex formation, a combination of spectral analyses and computer simulation was employed. RESULTS: The disappearance of the characteristic peaks of FA in Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed the formation of an inclusion complex between FA and HP-beta-CD. Thermogravimetry-derivative thermogravimetry (TG-DTG) studies demonstrated that the thermal stability of FA was enhanced due to the encapsulation of FA within HP-beta-CD. Molecular dynamics simulation also provided evidence that FA successfully penetrated the HP-beta-CD cavity, primarily driven by van der Waals interactions. The formation of the complex resulted in more compact HP-beta-CD structures. The bioavailability of FA was also strengthened through the formation of inclusion complexes with HP-beta-CD. CONCLUSIONS: The findings of this study have contributed to a deeper understanding of the interactions between FA and HP-beta-CD, potentially advancing a delivery system for FA and enhancing the bioavailability of insoluble active components. (c) 2024 Society of Chemical Industry.