Synthesis of interpenetrating network (IPN) hydrogels based on acrylic acid (AAc) and guar gum and its application as drug delivery for pyridoxine hydrochloride (vitamin B6)

Several interpenetrating network (IPN) type hydrogels were made by free radical crosslink copolymerization of acrylic acid (AA) in an aqueous solution of guar gum (GG). N’N-methylene bis acrylamide (MBA) was used as a crosslinker. The hydrogels were prepared by varying the synthesis variables such as concentration of the initiator, crosslinker, AA monomer and GG polymer in water. These hydrogels were characterized by FTIR, ¹³CNMR, SEM, XRD DTA-TGA and mechanical properties. The effect of the synthesis variables, solution pH, and the salts present in water on the swelling, diffusion and the network parameters of the hydrogels were studied. The release kinetics of a model drug pyridoxine hydrochloride (vitamin B6) was studied with these semi-IPN type polymers. The release rate of pyridoxine from the polymer at a solution pH of 7.5 was faster than its release rate at a pH of 1.5 due to its shrinkage at this low pH. The IPN prepared with 1wt% initiator, 1wt% crosslinker, 25 wt.% AA in water and 4 wt.% GG showed a high entrapment efficiency of 94% and a sustained release rate of 95% for pyridoxine drug in 30 h. The drug release data showed a close fitting to the Korsmeyer–Peppas model.