Swelling properties of Linseed hydrogel (LSH) were studied in deionized water and different physiological pH values, i.e., 1.2, 6.8 and 7.4. Analysis of the kinetics drawn from swelling data has revealed that swelling of LSH followed second order kinetics. The results indicated that swelling of LSH is greatly affected by different concentration of salts. Stimuli responsive on-off switching of LSH was studied in water/normal saline, water/ethanol and basic/acidic environment and found reversible. LSH swells maximum in water and at pH 7.4 while deswells abruptly in ethanol and at pH 1.2. The elongated porous structures uniformly organized in layers were observed in FE-SEM. LSH was used as a sustained release material for tablet formulation of diclofenac sodium. Drug release study followed non-Fickian diffusion. LSH sustained the release of drug even better than a commercially available formulation of diclofenac sodium.
Keywords: Drug release; Linseed hydrogel; Polysaccharides; Superporous hydrogel; Swelling–deswelling.
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