Synthesis, characterization and swelling responses of pH sensitive psyllium and polyacrylamide based hydrogels for the use in drug delivery (I)

In order to utilize the psyllium husk, a medicinally important natural polysaccharide, for developing the novel hydrogels meant for the controlled drug delivery devices, we have prepared psyllium and polyacrylamide based polymeric networks by using N,N'-methylenebis-acrylamide (N,N-MBAAm) as crosslinker. The polymeric networks thus formed were characterized with scanning electron micrography (SEM), FTIR and thermogravimetric analysis (TGA) techniques to study various structural aspects of the networks. This paper discusses the swelling responses of the polymeric networks as a function of time, temperature, pH and [NaCl]. Equilibrium swelling has been observed to be dependent on both structural aspects of the polymers and swelling environment. Percent swelling (Ps) has been observed to be decrease with increase in [NN-MBAAm] in the polymeric networks. It increases abruptly from 1437% to 4975% by changing the swelling medium from distilled water to solution of 0.5 M NaOH, which indicates the smart behavior of the network. Maximum Ps 4975 was observed at 6.4 x 10(-3) mol/L of [NN-MBAAm]. These observations indicate that these hydrogels are pH sensitive and have potential for use in colon specific drug delivery. (c) 2006 Elsevier Ltd. All rights reserved.