Immobilization of a nonsteroidal antiinflammatory drug onto commercial segmented polyurethane surface to improve haemocompatibility properties

ABRAHAM,G.A.; DE QUEIROZ,A.A.A.; SAN ROMAN,J

BIOMATERIALS

Elsevier Science, Ltd.

Lugar: Oxford, U.K.; Año: 2002 vol. 23 p. 1625 - 1638

0142-9612

A method has been developed in which a layer of p-aminosalicylic  acid (4-amino-2-hydroxybenzoic acid) (PAS), a water soluble pharmaceutical compound of the nonsteroidal anti-inflammatory drug (NSAID) class with antiaggregant platelet activity, is covalently immobilized on to a segmented polyurethane, Biospan™ (SPU) surface. Thus, SPU surfaces were modified by grafting of hexamethylenediisocyanate, and the free isocyanate remaining on the SPU surface were then coupled through a condensation reaction to amine groups of p-aminosalicylic acid.  The bonding of PAS from aqueous solution on to SPU surface was studied by ATR-FTIR, UV and fluorescence spectroscopy.  Plateau levels of coupled PAS were reached within  1.2 mg/cm2 using PAS solution concentrations of 1 mg/mL. The surface wettability of the polymeric films measured by contact angle indicate that the introduction of the PAS turns the surface more hydrophilic (qwater = 43.1º + 2.1º) relatively to the original SPU films (qwater = 70.3º + 1.9º). The in vitro albumin (BSA) adsorption shows that the PAS-SPU films adsorb more BSA (250 mg.mm-2) than the original SPU (112 mg.mm-2). Thrombogenicity was assessed by measuring the thrombus formation and platelet adhesion of the SPU containing PAS relatively to nonmodified SPU surfaces. The polymeric surfaces with immobilized  PAS had better nonthrombogenic characteristics as indicated by the low platelet adhesion, high adsorption of albumin relatively to fibrinogen and low thrombus formation, making them potentially good candidates for biomedical applications.