Improved blood compatibility by sustained release of heparin-deoxycholic acid conjugates in a PCL-PEG multiblock copolymer matrix.

The heparin and deoxycholic acid conjugate (heparin-DOCA) synthesized in this study has an amphiphilic property and could be completely dissolved in a co-solvent made of 1,4-dioxane (50 v/v%), n-propanol (25 v/v%), and water (25 v/v%). A polycaprolacton (PCL)-polyethylene glycol (PEG) multiblock copolymer was used as the coating matrix; this polymer also dissolved readily in the same co-solvent. Heparin-DOCA and the PCL-PEG multiblock copolymer were mixed well to produce a transparent coated film on an angio-catheter. The bioactivity of the released heparin-DOCA was determined by evaluating platelet adhesion and fibrin formation on the coated surfaces. The release rate could be controlled by the loading amount of the drug and drug release was maintained for 12 h. The released heparin-DOCA significantly prevented platelet adhesion and fibrin formation at the surfaces, as well as in the bulk in the plasma.