Apigenin-oxymatrine binary co-amorphous mixture: Enhanced solubility, bioavailability, and anti-inflammatory effect.

Apigenin (APG) is a functional ingredient in many foods, but its poor water solubility results in low bioavailability. This study aimed at delivering APG and improving bioavailability by a food-friendly co-amorphous formulation of APG with oxymatrine (OMT). After preparation of co-amorphous mixture (CM), characterized by powder x-ray diffraction and thermal analysis. Then, the presence of hydrogen bonds was confirmed by vibrational spectroscopy and molecular dynamics simulation. Furthermore, phase solubility and solubility studies, as well as dissolution test indicated that complexation occurred between APG and OMT in solution, which significantly improved the solubility and dissolution of APG-OMT CM. Additionally, pharmacokinetics and biological activity indicated that APG-OMT CM exhibited higher oral bioavailability and anti-inflammatory effect than pure APG. These results suggest that APG-OMT CM may be great potential for application in functional food. Importantly, the study provides a promising delivery system to improve the bioavailability of hydrophobic food ingredients.