Co-amorphous delivery systems based on curcumin and hydroxycinnamic acids: Stabilization, solubilization, and controlled release

Curcumin (CUR) is a polyphenol with a broad range of biological activity. However, CUR possesses low solubility and short half-life, which largely affects its bioavailability. The present study aimed to deliver CUR and control its release by co-amorphization strategy. Hydroxycinnamic acids, including p-hydroxycinnamic acid (pHCA) and ferulic acid (FA), were first employed as co-formers to prepare CUR-based co-amorphous systems (CAM). Combining powder X-ray diffraction, differential scanning calorimetry, spectra characterizations, and molecular simulations, the formations and intermolecular interactions of CUR-pHCA CAM and CUR-FA CAM were demonstrated. Further, the stability study showed that both CAM were stable for three months under 40 degrees C/75% RH. Interestingly, two CAM can obviously increase the solubility of CUR, meanwhile, exhibiting different controlled release behavior. Scanning electron microscope and contact angle analysis further revealed the release mechanism of CUR. Tight gels were generated on the surface of CUR-FA CAM. In contrast, loose spaces were formed on the surface of CUR-pHCA CAM, which allowed water intrusion into the particles and continuous dissolution of CUR. These results suggested that the release rate of CUR from CAM could be controlled by employing different hydroxycinnamic acids as co-formers. Overall, the current study offers references to deliv-ering functional ingredients in food systems.