Synthesis of chitosan-g-itaconic acid hydrogel as an antibacterial drug carrier: optimization through RSM-CCD

In this research, the graft copolymer of itaconic acid (IA) onto chitosan (CS) was synthesized in an aqueous medium using ammonium persulfate (APS) as an initiator. Monomer amount, initiator concentration, temperature and reaction time are taken as the process variables and optimized with RSM in order to maximize the graft percentage (106% in the hydrogel synthesized using 1 g CS, 1.48 g IA, 23.8 mmol/Lit APS at 72 °C in 4.6 h). The crosslinking of graft copolymer of chitosan/itaconic acid (CS-g-IA) was carried out with optimized parameters and using various content of N,N′-methylene bisacrylamide (MBA) as a crosslinker, in a homogeneous medium. The products’ structure was established using FTIR spectroscopy. Morphology of the optimized graft copolymer and the hydrogel was examined by scanning electron microscopy (SEM), and the surface of the hydrogel has been appeared as porous, rough and irregular. Investigation of thermal stability by thermal gravimetric analysis (TGA) showed that grafting reaction has improved thermal stability of CS. Also, the swelling behavior and antibacterial properties of the synthesized hydrogel were studied and the results showed that the hydrogel had good swelling capacity (1362%). In addition, ciprofloxacin, as an antibiotic drug model, was loaded onto the chitosan-g-itaconic acid hydrogel. The cumulative release ratios of ciprofloxacin from the synthesized hydrogel were 60% in pH 7.4 solutions within 140 min.