Synthesis of poly[3‐(methacryloylamino) propyl trimethylammonium chloride‐co‐methacrylic acid] copolymer hydrogels for controlled indomethacin delivery

Abstract

AbstractStimulus responsive hydrogels are being considered as one of the most exciting biomaterials of current generation. A novel hydrogel based on poly 3‐[(methacryoylamino) propyl trimethylammonium chloride‐co‐methacrylic acid] (PMAPTACMAAc) copolymer was synthesized by free radical aqueous copolymerization. The water uptake of the hydrogels was investigated as a function of temperature and pH. The in vitro release properties of the PMAPTACMAAc hydrogels were analyzed under simulated body fluid (pH 7.4) by loading indomethacin (IND) as a model drug. The XRD study of the hydrogel revealed the amorphous nature of the copolymer and provided evidence that crystalline IND was entrapped in the hydrogel matrix. The DSC study showed the presence of single glass transition temperature in the thermogram which indicated the formation of random copolymers. The prepared hydrogels showed typical polyampholyte behavior and swelling was affected by the monomer feed ratios in the hydrogels. The morphological study on the hydrogels showed the three dimensional (3D) porous nature of the PMAPTACMAAc‐5 gel with pore size ranging from 10 to 40 μm. The kinetics of the cumulative IND release shows that the gel follows a non‐Fickian release mechanism. In vitro cytotoxicity of the hydrogel (PMAPTACMAAc‐5 gel) on RAW 264.7 murine macrophages showed that the hydrogel was biocompatible and not toxic as the viability was maintained. The hydrogel with a 90 : 10 feed ratio of MAAc and MAPTAC was better than the other developed formulations. The results suggest that the hydrogels could be employed as a sustained release formulation for targeted delivery of IND, for example to the colon. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013