Interpenetrating polymer networks hydrogels of chitosan and poly(2-hydroxyethyl methacrylate) for controlled release of quetiapine

Polymer networks interpenetrated by chitosan and 2-hydroxyethyl methacrylate (HEMA) were synthesized. The FTIR spectra confirmed crosslinking of chitosan and polymerization of HEMA. The swelling properties were studied at different pHs and depend particularly on the chitosan content of the material and the pH sensitivity of the network. DSC studies showed two vitreous transitions at approximately 98 degrees C and 155 degrees C, which correspond to the networks of pHEMA and chitosan respectively, demonstrating that the materials obtained are amorphous and interpenetrated. Creep-recovery and stress relaxation studies showed that the materials demonstrate viscoelastic behavior. Quetiapine was used as a pharmacological model for studies of controlled release, and it was found that the process is controlled by diffusion and by relaxation of the polymer network. Finally, the synthesized materials were degraded using lysozyme under simulated physiological conditions. A higher degree of degradation was observed in conjunction with an increase in the chitosan content.