Hemocompatible polymers on hydrophobic porous polymers

Abstract

The present invention relates to providing a porous, hydrophobic polymer with a hemocompatible substance and to the materials produced thereby. One embodiment of the present invention relates to the providing of expanded poly(tetrafluoroethylene) with one or more complexes of heparin, typically containing heparin in combination with a hydrophobic counter ion. The hemocompatible substance 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 substance material in the solvent mixture. Typical first solvents wetting hydrophobic polymers include non-polar such as hydrochlorofluorocarbons. 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. A typical example providing a heparin complex to an endoluminal stent, consisting of coating DURAFLO onto an ePTFE stent-covering material.