IN-VITRO EVALUATION OF HEPARIN ADSORPTION DURING HEMOPERFUSION WITH DOWEX 1X2 ANION-EXCHANGE RESIN

Haemoperfusion treatments have found clinical applications in various pathologies, even though problems due to the insufficient biocompatibi lity of sorbents have often limited its employment. Among these proble ms, there is that of heparin adsorption which can determine coagulatio n disorders or the necessity of a dosage correction during the extra c orporeal circulation. The aim of the study was to test the influence o f different methods of coating on heparin adsorption from an anion exc hange resin coated with poly-hydroxyethyl-methacrylate. Eight haemoper fusion cartridges were prepared using 8 g of resin for each (4 cartrid ges contained resin coated by spray-coating technique and 4 coated by phase-separation one). Haemoperfusion was performed by using 600 IU of heparin (25,000 IU) corresponding to 0.12 ml in 500 ml of swine blood and a closed circuit. Blood flow rate was maintained at 15 ml/min and the circuit pressure was 70 torr during haemoperfusion. Blood samples were withdrawn at timed intervals before and after the column in orde r to evaluate blood heparin levels. The results demonstrated the super iority of the phase-separation technique that does not permit any inte ractions between adsorbent substance and drug. As a result of this, th e adjustment of the dosage may not be necessary during further in vivo experiments.