Antithrombogenic Heparin-Bound Polyurethanes

Abstract

Many kinds of heparin-bound polyurethanes have been developed. Polyurethanes are a family of elastomers displaying better blood-compatibility than other polymeric materials. It is useful to modify this material by heparinization. Several approaches to heparinization have been devised: 1) a general method of heparinization, applicable to all polymeric materials, 2) a heparinization method specific to polyurethanes, and 3) the design of heparinizable polyurethane derivatives. These three approaches are first explained in detail. Then, the antithrombogenic mechanism of the heparinized polymers is discussed. Finally, the interactions of the heparinized polymers with blood coagulation factors, plasma proteins, and platelets are discussed.

Biopolymers; Definition, Classification and Applications

“…Polymer membranes immobilize platelet tranquilizers to yield highly nonthrombogenic materials. Ebert et al; [59] report that PGI2-immobilized polystyrene beads has a great inhibition effect on platelet in both adhesion and activation and their team also pointed out that adhesion and activation of platelets are suppressed on heparin-immobilized materials too [60,61].…”

Modification of Biomaterials to Improve Blood Compatibility

“…We have attached the drug to the hydroxylic polymers dextran and poly(ethylene glycol) by direct esterification with the aid of the coupling agent dicyclohexyl carbodiimide (DCCI) to obtain adducts such as those shown in [2) and [3).…”

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“…One of the most widely employed approaches in the synthesis of blood compatible materials is heparinization, in which synthetic polymers are coated or immobilized with heparins (Ito, 1987). Heparins are a linear anionic polysaccharide chain; they are typically heterogeneously sulphated on alternating L-iduronic acid and D-glucosamino sugars, and are nearly ubiquitous in animal tissues as heparan sulphate proteoglycans on cell surfaces and in the extracellular matrix (Casu, 1995).…”