New polyurethanes able to bind high amounts of heparin, suitable as biomedical compositions

The synthesis of new segmented polyurethanes containing different amounts of N,N-diethylaminoethyl-N-2,2 hydroxymethylpropionamide, and able to bind, after, suitable quaternization, high amounts of heparin, is described. The quaternization is carried out on organic solutions of the polymers. Polymers have been characterized by spectroscopic techniques, molecular weight measurements and differential scanning calorimetry. The heparin content of the polymer films was determined by a colorimetric system, and its biological activity was evaluated in vitro by activated thromboplastin time (APTT) measurements. The distribution of heparin on the surface and in bulk of the heparinized films was evaluated by scanning electron microscopy (SEM) with X-ray energy dispersive spectroscopy.