Study on preparation and swelling kinetics of P(AA‐<i>co</i>‐C₈PhEO₁₀Mac) pH‐sensitive hydrogel <i>in vitro</i> drug release study

Abstract

ABSTRACT Stimuli‐sensitive hydrogels are one of the most promising and versatile materials with many potential applications. In this article, a pH‐sensitive hydrogel [P(AA‐ co ‐C 8 PhEO 10 Mac)] was synthesized by the free‐radical cross‐linking polymerization of acrylic acid (AA) and octylphenyl polyoxyethylene methacrylate macromonomer (C 8 PhEO 10 Mac). Swelling property, swelling, and deswelling kinetics of the hydrogels in different pH media were studied and hydrogel microstructures were investigated by means of scanning electron microscopy (SEM). Theophylline was chosen as a model drug and the controlled‐release properties of hydrogels were pilot studied. The results showed that the P(AA‐ co ‐C 8 PhEO 10 Mac) hydrogel has a porous structure, both the rapid swelling and deswelling rate, and good pH sensitivity characteristics; The swelling ratios of the gels in stimulated intestinal fluids (SIF, pH = 7.4) were higher than those in stimulated gastric fluids (SGF, pH = 1.4). The in vitro cumulative release data were analyzed using an empirical equation to compute the diffusion exponent ( n ), whose values suggest a non‐Fickian mode of transport. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1981–1989, 2013