Chitosan derivatives: Coating onto polymer substrates

Abstract

<P>PHOTOCROSSLINKABLE ITACONYL SULFATED CHITOSAN (ISC) HYDROGEL WAS PREPARED STARTING FROM SULFATION OF CHITOSAN USING SULFUR TRIOXIDE PYRIDINE COMPLEX AS SULFATING AGENT. THIS WAS FOLLOWED BY ITACONYLATION OF SULFATED CHITOSAN WITH ITACONIC ANHYDRIDE. THE OBTAINED ISC IS PHOTOCROSSLINKABLE UNDER UV 365 NM TO FORM A HYDROGEL. THIS HYDROGEL WAS IMMOBILIZED ONTO POLYMERIC SUBSTRATES. THE ANTICOAGULANT PROPERTIES OF THE COATED SUBSTRATES WERE ASSAYED BY APTT, PT AND FIBRINOGEN CONCENTRATION. ISC COATED SUBSTRATES SHOWED MARKEDLY IMPROVEMENT FOR APTT, BUT NOT PT. THIS RESULT INDICATED THAT THE ISC COATED SUBSTRATES MAY INHIBIT THE FACTORS THAT TRIGGER THE INTRINSIC PATHWAY COAGULATION CASCADE BUT MAY NOT INHIBIT FACTORS THAT TRIGGER THE EXTRINSIC PATHWAY. THE ISC COATED SUBSTRATES DID NOT SHOW MUCH DIFFERENCE FOR FIBRINOGEN CONTENT COMPARED TO THAT OF CONTROL VALUE. THUS, NO OR LESS PLASMA PROTEIN ADSORPTION OCCURRED WHEN BLOOD CAME INTO CONTACT WITH SURFACES OF THE COATED SUBSTRATES. </P