Synthesis and properties of carboxymethylcellulose (CMC) graft copolymer with on-off switching properties for controlled release of drug

Novel biopolymer-based superabsorbent hydrogels were prepared by grafting crosslinked poly (N-vinyl pyrollidin and 2-Acrylamido-2-methyl propan sulfonic acid (PNVP-co-PAMPS) chains onto CMC backbones through a free radical polymerization method. A proposed mechanism for superabsorbent hydrogel formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy. The morphology of the samples was examined by scanning electron microscopy (SEM). The concentration of released metronidazole loaded was monitored at 245 nm on the UV spectrophotometer. Water absorption of the hydrogel could be switched on and off swiftly by control of pH of the surrounding environment. Therefore, the synthesized hydrogels in this study can be used as a drug delivery system and that the drug release can be controlled by the pH of solution. The release rate of metronidazole from hydrogel at pH 7.4 was higher than that at pH 1.6, due to the increased swelling capacity of the hydrogel.Key words: CMC, hydrogels, release drug, N-vinyl pyrollidin, 2-acrylamido-2-methyl propan sulfonic acid