Synthesis of iron-crosslinked chitosan succinate and iron-crosslinked hydroxamated chitosan succinate and their in vitro evaluation as potential matrix materials for oral theophylline sustained-release beads.

Chitosan succinate (CS) and hydroxamated chitosan succinate (HCS) were prepared. The generated semisynthetic polymers were employed in the formation of drug-loaded, iron(III)-crosslinked polymeric beads. Infrared spectroscopy was employed to prove the crosslinking. The produced beads were evaluated in vitro as drug prolonging and potentially orally administered delivery system. Theophylline was used as the loaded model drug. The generated beads proved to be successful in prolonging drug release. Iron leaching from the generated beads was minimal (<2%), and it only took place under acidic conditions (pH 1).