Synthesis and antithrombogenicity of polyetherurethaneurea containing quaternary ammonium groups in the side chains and of the polymer/heparin complex.

Novel polyetherurethaneureas containing tertiary amino groups in the side chains (PAEUU) were synthesized, quaternized with different alkyl halides (Q-PAEUU), and heparinized (H-PAEUU). The antithrombogenicity of PAEUU in vitro was improved by quaternization, and further by heparinization. The excellent antithrombogenicity of H-PAEUU was controlled by the kind of quaternizing agent through the polar effect of quaternizing agent on the water content and through the steric effect of quaternizing agent on the heparin content of H-PAEUU. The antithrombogenicity of H-PAEUU was found to be affected by the water content more strongly than by the heparin content. H-PAEUUs containing tertiary amino groups in the main chain, which were synthesized previously, showed a little better short-term antithrombogenicity than the present H-PAEUUs containing tertiary amino groups in the side chains. Since ammonium groups in the side chains of Q-PAEUU impose little steric hindrance against the heparin adsorption, the release of heparin from the side chains of H-PAEUU was slower but lasted longer than that from the main chain. Therefore, the present H-PAEUU is expected to be a long-term antithrombogenic material.