Medical device coated with interpenetrating network of hydrogel polymers

Claim 2

A medical device comprising an organic polymer substrate material having a coating thereon, the coating comprising an interpenetrating network of two different hydrogel polymers, one of which is a polyurethane/polyurea hydrogel polymer, the polyurethane/polyurea hydrogel polymer being linked to the substrate material by covalent urea linkages.

Claim 3

A device as in claim 1 wherein the second of said two hydrogel polymers is selected from the group consisting of polysaccharide polymers, metal salts of polysaccharide polymers, poly(ethylene oxide)homopolymers and poly(N-vinylpyrrolidone)polymers.

Claim 4

A device as in claim 1 wherein said substrate material is selected from the group consisting of polyethylene terephthalate, polyether-polyester block copolymers, polyether-polyamide block copolymers, polyamide, polyimides, polyurethanes, polyofin polymers, hydrocarbon elastomers, nitrile rubbers, ethylene/alkyl acrylate copolymers and natural rubber.

Claim 5

A device as in claim 1 formed by a process comprising the steps of: a) providing the substrate material with isocyanate-reactive chemical groups on the surface thereof, at least some of which are amine groups; b) forming a tie-coat layer by applying a first formulation to the substrate surface, the first formulation comprising an isocyanate functional hydrogel-forming prepolymer formed by reaction of a polyether and a polyisocyanate compound, whereby some of the isocyanate groups of the prepolymer react with said amine groups to form urea linkages between the substrate material and the prepolymer and some of the isocyanate groups of the prepolymer remain unreacted; and c) applying a second formulation to the tie-coat layer, the second formulation having therein at least one isocyanate-reactive component and comprising an aqueous solution of a second hydrogel polymer different from said polyurethane/polyurea hydrogel polymer, whereby water in the second formulation forms a hydrogel with tie-coat layer prepolymer; the second hydrogel polymer penetrates into the tie-coat layer; and the free isocyanate groups of the tie-coat layer prepolymer react with said isocyanate-reactive component in the second formulation to form said polyurethane/polyurea hydrogel polymer, such that at least a portion of the tie-coat layer and the barrier layer are commingled and form said interpenetrating network of polyurethane/urea and second hydrogel polymers.

Claim 6

A device as in claim 4 wherein said amine groups were provided on substrate material surface by treatment thereof with a plasma of a nitrogen-containing gas.

Claim 7

A device as in claim 4 wherein said second hydrogel polymer is a poly(N-vinylpyrrolidone)polymer.

Claim 8

A device as in claim 1, the device being a catheter, a catheter balloon or a stent.