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- β -cyclodextrin (HP- β -CD), with its distinctive hollow structure, offers the potential for encapsulating hydrophobic molecules. The formation of an inclusion complex between FA and HP- β -CD may therefore be a viable approach to address the inherent limitations of FA. To investigate the underlying mechanism of the FA/HP- β -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- β -CD. Thermogravimetry-derivative thermogravimetry (TG-DTG) studies demonstrated that the thermal stability of FA was enhanced due to the encapsulation of FA within HP- β -CD. Molecular dynamics simulation also provided evidence that FA successfully penetrated the HP- β -CD cavity, primarily driven by van der Waals interactions. The formation of the complex resulted in more compact HP- β -CD structures. The bioavailability of FA was also strengthened through the formation of inclusion complexes with HP- β -CD. CONCLUSIONS The findings of this study have contributed to a deeper understanding of the interactions between FA and HP- β -CD, potentially advancing a delivery system for FA and enhancing the bioavailability of insoluble active components. © 2024 Society of Chemical Industry.