The present invention relates to coating a porous, hydrophobic polymer with
a hemocompatible coating and to the materials produced thereby. One
embodiment of the present invention relates to the coating of expanded
poly(tetrafluoroethylene) with one or more complexes of heparin, typically
containing heparin in combination with a hydrophobic counter ion. The
hemocompatible coating is dissolved in a mixture of solvents in which a
first solvent wets the polymer to be coated and the second solvent
enhances the solubility of the hemocompatible coating material in the
solvent mixture. Typical first solvents wetting hydrophobic polymers
include non-polar such as hydrocholorofluorocarbons. Typical second
solvents include polar solvents such as organic alcohols and ketones.
Azeotropic mixtures of the second solvent in the first solvent are used in
some embodiments of the present invention although second solvents may be
employed in a range of concentration ranges from less than 0.1% up to
saturation. An example is provided of coating heparin complex onto an
endoluminal stent, typically consisting of coating DURAFLO onto an ePTFE
stent covering material.
