STUDY OF HEMODIALYSIS MATERIALS - PHYSICOCHEMICAL AND BIOLOGICAL CHARACTERIZATION OF EVALVA, EVAPA AND HEPARINIZED EVAPA

Partially hydrolyzed ethylene/vinyl acetate copolymers were modified b y the covalent binding of a heparin-complexing polymer and further hep arinized in order to improve their blood compatibility. These heparini zable polymeric materials (EVAPA) were obtained by a two-step reaction between an ethylene/vinyl alcohol/vinyl acetate (EVALVA) terpolymer, and the heparin complexing polymer N2LL. The physico-chemical characte rization of EVALVA, EVAPA and heparinized-EVAPA was carried out throug h thermal analysis, SEM, contact angle, potentiometric measurements, w ater uptake and FT-IR spectroscopic measurements. The biocompatibility of the above-mentioned samples was evaluated using in vitro methods, through the determination of heparin release in phosphate buffer solut ion (PBS) and in human plasma, and with the investigation of hemostasi s activation.