Introduction

The invention describes the synthesis of new polymeric adsorbent materials able to sequester the anticoagulant heparin from aqueous solutions and biological fluids. These are haemocompatible materials that could find application in the development of blood filters useful in surgery and dialysis to restore normal coagulation parameters after the use of heparin.

Technical features

Heparin is an anticoagulant drug used in hemodialysis to prevent clot formation in extracorporeal blood circulation circuits. Heparinized patients are exposed to a high risk of bleeding and have a probability of developing chronic diseases. Controlling the use of the anticoagulant is therefore a clear clinical need. We have synthesized a new adsorbent cryopolymer that allows the selective neutralization of heparin. The material is hemocompatible and does not interfere with plasma proteins and other blood components. These properties could allow the design and development of a new filtering device able to neutralize the excess of heparin before the blood returns to the patient’s circulation.

The cryogel is an acrylic copolymer with adaptable lysine concentrations. As lysine is a basic amino acid, at physiological pH, it confers to the material a positive electric charge. Heparin is the biological molecule with the highest negative charges ( ̴ 76 for high molecular weight heparin), so recognition is mainly regulated by an electrostatic mechanism. The absorption performances were measured with three materials with different compositions in lysine, in suitably heparinized solutions of water, physiological buffer, plasma and whole blood. The results show that 1 g of cryogel with 50% lysine is able to neutralize 160 mg of high molecular weight heparin. During dialysis, a patient with an average body weight of 70 kg is treated with 4500 IU of heparin, corresponding to  ̴  25 mg. Extrapolating, we can say as a filter with 200 mg of material could be enough to neutralize all the heparin of the dialysis cycle.

Possible Applications

• Hematology and coagulation;
• Medical devices;
• Surgery;
• Nephrology and Dialysis.

Advantages

• Enhanced safety in extracorporeal blood circulation protocols;
• Better quality of life for dialysis patients;
• Cost reduction for the NHS.