Tissue-compatible medical device and method for manufacturing the same

DETAILED DESCRIPTION The class of materials used to form the polyurethane elastomeric matrix of the present invention, which as previously related are known per se, are referred to as "silicone polyurethanes" for the purposes of the present invention.
The preparation and properties of such materials are not critical for the present invention and can be derived from the state of the art, depending on the desired requirements without inventive activity within the scope of the teachings herein.
In particular, the preparation and properties of such materials are set forth in previously mentioned U.
S.
Pat.
No.
3,562,352 (Nyilas) and European Pat.
No.
0 068 385, both of which are hereby incorporated by reference.
The polyol compounds used in the manufacture of the polyurethane elastomers of the present invention may comprise any compound of the type used for reaction with isocyanate to form polyurethanes.
Included in this category are diol compounds such as polyethers, polyesters and polycaprolactones.
The organic silicone polymer compounds used in the present invention are preferably polysiloxanes such as polydimethylsiloxane, methylphenylsiloxane, fluoroalkylmethylpolysiloxane and the like.
Further, it is possible to use any isocyanate compound of the type used for the manufacture of polyurethane, although diisocyanates are particularly preferred.
The medical device of the present invention can penetrate living body tissues due to its excellent tissue compatability while providing a substantially increased delivery capacity for oligodynamic agents which release metal ions when exposed to body tissues.
The spatially uniform embedment of 1 to 15 wt.
% of these oligodynamic agents according to the invention in the silicone polyurethane matrix increases the usable amount of the available ions over the customary coatings by 40% or more.
Because of the matrix utilized herein and the unique nature in which it is formed, the medical devices of the present invention are capable of releasing these metal ions in controlled amounts over an extended period of time to each of its exposed surfaces when in contact with body fluids and the like