Polyelectrolyte complexes of chitosan with dextran sulphate. Synthesis and characterization

Chitosan (CS), the unique cationic groups-containing polysaccharide, is a natural, renewable, nontoxic and biodegradable material, considered as an ecologically-friendly product. Several studies on the obtaining of intermolecular complexes (IMC) between CS and natural or synthetic anionic polyelectrolytes have been reported. CS and dextran sulphate (sodium salt form) (DS), among other applications, may be also used to obtain various complexes with special applications in protein, cell and enzyme encapsulation. The present investigation discussed some new results on CS interaction with DS, for obtaining suitable systems for controlled release of drugs and of other bioactive agents. The interaction between these two partners was investigated in solution by conductometric, Potentiometric and turbidimetric titration, and in solid phase, by FTIR spectroscopy and thermogravimetric analysis. All titration methods confirmed the formation of complexes in a stoichiometric ratio between partners. Solid phase analysis of the obtained complex by FTIR spectroscopy evidenced the presence of new bands characteristic of electrostatic interaction.