Characterization, dynamic swelling behaviour and solute transport in cationic networks with applications to the development of swelling-controlled release systems

Poly(diethylaminoethyl methacrylate-co-hydroxyethyl methacrylate), poly(diethylaminoethyl acrylate-co-hydroxyethyl methacrylate) and poly(methacrylaminopropyl ammonium chloride-co-hydroxyethyl methacrylate) were synthesized by free radical polymerization and characterized using differential scanning calorimetry and dynamic mechanical analysis. Transport of citrate-phosphate-borate buffer solutions into the polymer network was investigated at different pH values. The anomalous transport behaviour in these polymers was analysed and the swelling front velocity was determined. The effect on the transport mechanism of polymer structural characteristics, such as the molecular weight between crosslinks and the concentration of ionizable pendent groups, was studied. The transport was found to be anomalous at acidic pH values where the polymer networks were ionized. Transport of oxprenolol HC1, insulin, myoglobin and albumin was investigated and was found to be strongly dependent on the mesh size of the polymer network.