Abstract

The paper addresses development of novel pH sensitive interpenetrating polymeric network (IPN) beads composed of chitosan-glycine-glutamic acid cross linked with glutaraldehyde and their use for controlled drug release. A comparative study has been carried out on these IPN beads with the beads that of chitosan, chitosan-glycine and chitosan-glutamic acid cross linked with glutaraldehyde. The beads were characterized by FTIR to confirm the cross linking reaction and drug interaction with cross linked polymer in beads, scanning electron microscopy (SEM) to understand the surface morphology and internal structure and DSC to find out the thermal stability of beads. The swelling behavior of the beads at different time intervals was monitored in solutions of pH 2.0 and pH 7.4. The release experiments were performed in solutions of pH 2.0 and pH 7.4 at 37°C using chlorpheniramine maleate (CPM) as a model drug. The swelling behavior and release of drug were observed to be dependent on pH, degree of cross linking and their composition. The results indicate that the newly constructed cross linked IPN beads of chitosan-glycine-glutamic acid might be useful as a vehicle for controlled release of drug. The kinetics of drug release from beads was best fitted by Higuchi’s model in which release rate is largely governed by rate of diffusion through the matrix.

Key words: Cross-linked beads, chitosan, chlorpheniramine maleate, glycine, glutamic acid, controlled drug release.