Release kinetics and binding interactions of curcumin‐encapsulated nanoparticles released from chitosan‐graft‐(methoxy poly(ethylene glycol)‐block‐polycaprolactone) injectable hydrogels

Abstract Injectable hydrogels are alternative materials for drug delivery in biomedical applications. Most injectable hydrogels are derived from stimuli‐responsive polymers that can respond to the changes of physical and/or chemical properties of the environment, such as temperature and pH variation. In this study, chitosan‐ graft ‐(methoxy poly (ethylene glycol)‐ block ‐polycaprolactone) injectable hydrogels were loaded with curcumin in different concentrations. The loading capacity and encapsulation efficiency of curcumin in such hydrogels were increased and decreased respectively with increasing curcumin concentrations. The encapsulation efficiency, however, was more than 90% for all formulations. Such hydrogels demonstrated curcumin release that proceeded in a sustained manner. The release profiles followed Korsmeyer‐Peppas and zero‐order kinetic release models which suggested that the release was facilitated by drug diffusion and the erosion of the self‐assembled polymeric networks. The curcumin released from the hydrogels was found as encapsulated core‐shell nanoparticles, the size of which depended on the loading concentration. A combination of fluorescence spectroscopy and thermodynamics analysis showed that van der Waals interactions and hydrogen bonds were major binding forces between curcumin and the copolymers. In addition, the curcumin‐encapsulated nanoparticles showed a progressive reduction in survival of the cervical cancer HeLa cell line, as shown in in vitro cytotoxicity experiments. © 2023 Society of Industrial Chemistry.