Microwave-assisted grafting of acrylamide on a natural xylan gum for controlled drug delivery

Natural polymers offer significant advantages (biocompatibility, biodegradability, and non-toxicity) over synthetic polymers besides some reported disadvantages. However, natural polymeric structures can be modified by the grafting process for desired physicochemical properties. The purpose of the present research was to develop polyacrylamide-grafted xylan gum (XG) via green synthesis using microwave-assisted free radical polymerization with the use of ceric ammonium nitrate (initiator). Several batches of the grafted XG were prepared by varying three independent process variables (amount of acrylamide, ceric ammonium nitrate, and microwave irradiation time) and subsequently characterized for surface, physicochemical, and biodegradation properties. The grafted XG from the optimized batch was further used in the preparation of metoprolol succinate tablets, which showed desired properties including in vitro controlled release of highly water-soluble drug for more than 8 h following zero-order kinetics as the best-fit model. Therefore, the grafted XG, prepared using the microwave-assisted graft copolymerization method, proved its efficiency as an excellent pharmaceutical excipient for its use in controlled release systems for drugs with high aqueous solubility.