Polymeric systems based on derivatives of ethylene-vinyl alcohol copolymers

To obtain polymers with improved hemocompatibility properties, commercial e thylene-vinyl alcohol copolymers (EVAL) were chemically modified, by the in troduction of stearoyl groups to bind albumin and quaternary ammonium group s to bind heparin. These novel polymer composites were characterized by FT- IR and H-1-NMR spectroscopy. The amount of heparin and albumin bonded by th ese polymers were determined and the influence of the adsorption sequence ( heparin + albumin or vice versa) was evaluated. The amount of adsorbed albu min was proportional to the stearoyl content of the polymer. When heparin w as exposed to polymer surfaces containing quaternary ammonium groups, the a mount of bonded heparin was proportional to the content of positively charg ed groups. An in vitro evaluation of the anti-clotting properties and of th e adhesion characteristics of the polymer surfaces containing both stearoyl groups and quaternary ammonium groups exhibited, after heparinization, goo d anticoagulant activity. This activity was retained after the albuminizati on. Platelet adhesion tests showed that albuminization of polymer films con taining only stearoyl residues improved their behavior towards platelet adh esion.