Solid State Synthesis of Hyaluronic Acid–Quercetin Conjugate: Sustainable Protocol to Improve the Biological Activity of Quercetin

Herein, a sustainable solid-state procedure is employed for the synthesis of a water-soluble molecule obtained by linking hyaluronic acid to the hydrophobic quercetin (HA-QCT). The micellar self-aggregation of the developed conjugate suggested its employment as a drug delivery nano-system, considering the numerous biological activities of QCT. Indeed, the spectroscopic characterization (ultraviolet-visible and Fourier transform infrared) ensured that the QCT maintained its chemical integrity. In addition, a cytotoxicity test revealed that HA-QCT can be employed as a biocompatible drug vehicle for pharmacological purposes. A preliminary colorimetric test also confirmed that QCT retained its anti-oxidant activity.