Heparinized polyurethanes: in vitro and in vivo studies

Area of Science:

• Biomaterials Science
• Medical Device Engineering
• Thrombosis Research

Background:

• Polyurethane (PU) materials are widely used in medical devices.
• Preventing thrombus formation on implanted devices is critical for patient safety.
• Heparin is a well-established anticoagulant used to improve device biocompatibility.

Purpose of the Study:

• To optimize heparin immobilization chemistry on PU surfaces.
• To evaluate the antithrombotic efficacy of immobilized heparin (HI) in vitro and in vivo.
• To compare the performance of HI with a heparin-releasing (HR) system.

Main Methods:

• Adapted heparin immobilization chemistry using alkyl spacer arms on PU.
• Assessed in vitro biological activity by measuring thrombin and Factor Xa inactivation.
• Evaluated in vivo antithrombogenicity using canine femoral and jugular vein catheter models.

Main Results:

• Immobilized heparin retained significant anticoagulant activity, binding and inactivating thrombin and Factor Xa.
• In vivo studies showed a significant reduction in thrombus formation on HI-PU catheters compared to untreated controls.
• Heparin-releasing (HR) PU catheters demonstrated superior antithrombogenicity compared to HI-PU and untreated controls.

Conclusions:

• Heparin immobilization on PU surfaces is a viable strategy to enhance antithrombogenicity.
• Immobilized heparin maintains biological activity and reduces thrombus formation in vivo.
• Heparin-releasing systems offer enhanced antithrombotic benefits for medical devices.