Chitosan-graft-poly (2-hydroxyethyl methacrylate-co-itaconic acid) has been synthesized for different feed ratios of 2-hydroxyethyl methacrylate and itaconic acid and characterized by FT-IR, thermogravimetry and swelling in simulated biological fluids (SBF) and evaluated as a drug carrier with model drug, tramadol hydrochloride (TRM). Grafting decreased the thermal stability of chitosan. FT-IR spectra of tablet did not reveal any molecular level (i.e. at <10 nm scale) drug-polymer interaction. But differential scanning calorimetric studies indicated a probable drug-polymer interaction at a scale >100 nm level. The observed Korsmeyer-Peppas's power law exponents (0.19-1.21) for the in vitro release profiles of TRM in SBF and other drugs such as 5-fluorouracil (FU), paracetamol (PCM) and vanlafaxine hydrochloride (VNF) with the copolymer carriers revealed an anomalous drug release mechanism. The decreased release rates for the grafted chitosan and the enhanced release rate for the grafts with increasing itaconic acid content in the feed were more likely attributed to the enhanced drug-matrix interaction and polymer-SBF interactions, respectively. The different release profiles of FU, PCM, TRM and VNF with the copolymer matrix are attributed to the different chemical structures of drugs. The above features suggest the graft copolymer's candidature for use as a promising oral drug delivery system.

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A sequence of semi‐interpenetrating polymer network (semi‐IPN) were synthesized by free radical photo copolymerizing acrylic acid and isopropyl acrylamide (NIPAAm) in aqueous sodium alginate (NaAlg). Their structures (FT‐IR), thermal stability (TG/DTG), morphology (SEM), mechanical properties, reactive blue 4 (RB 4) dye adsorption (624 mg/g) and its dying characteristics, reusability of dye and adsorbent were evaluated. TG thermograms of semi‐IPN in air revealed zero order kinetics for initial step thermal degradation with an activation energy of 68.68 kJ/mol. Dye adsorption showed best fit for Langmuir adsorption isotherm and the kinetics followed pseudo‐second‐order model. The water and dye diffusion kinetics followed non‐Fickian mechanism. The changes in thermodynamic parameters namely Gibbs free energy (ΔG°), entropy (ΔS°) and enthalpy (ΔH°) indicated that the adsorption was spontaneous and exothermic process for RB 4/semi‐IPN system. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40968.