Novel polyelectrolyte complexes between N-carboxyethylchitosan and synthetic polyelectrolytes

Novel polyelectrolyte complexes (PEC) between the polyampholyte N-carboxyethylchitosan (CECh) and polyacid or polybase have been prepared. The complex formation between CECh and poly(2-acryloylamido-2-methylpropanesulfonic acid) (PAMPS), poly(acrylic acid) (PAA) or poly(ethylene imine) (PEI) has been studied. The complex CECh/PAMPS is formed in the pH range from 1.2 to 6.0. The complex CECh/PAA is formed in the range 4.8-6.0 and CECh/PEI—from pH 5.4 to 7.0. The stoichiometry of the complexes depends on the pH value of the medium. In case of CECh/PAMPS and CECh/PAA the maximum quantity of complex is formed in excess of CECh and in the case of CECh/PEI—in excess of PEI. It has been shown that PEC formation between CECh and PAMPS improves the haemocompatibility of CECh.