Facile Tuning of the Photoluminescence and Dissolution Properties of Phloretin through Cocrystallization

Phloretin (PHL) is an abundant dietary flavonoid possessing several pharmacological activities but with poor aqueous solubility and low bioavailability. Herein, two new cocrystals of phloretin-nicotinamide (PHL-NIC) and phloretin-isonicotinamide (PHL-INM) have been synthesized and characterized by various analytical methods. Two cocrystals exhibited different crystal packing and intermolecular interactions. Strong photoluminescence was observed in the PHL-NIC cocrystal while not in the PHL-INM cocrystal and pure PHL. Density functional theory (DFT) calculations were conducted to interpret the distinct photoluminescent behavior between the cocrystals. Both cocrystals exhibited enhanced dissolution performance in comparison with the pure PHL. This study demonstrates that cocrystallization is a powerful strategy to tune the physical properties of functional organic solids.