Medical device polymer

Claim 1

A method for forming a medical device the function of which requires exposure to the tissue of a patient, comprising: forming an internal polymer layer defining a reservoir for a therapeutic agent selected from the group consisting of antithrombogenic agents, antiplatelet agents, prostaglandins, thrombolytic drugs, antiproliferative drugs, antirejection drugs, antimicrobial drugs, growth factors, and anticalcifying agents, that inhibits adverse reaction to the presence of the device, the internal polymer layer comprising a polymer selected from the group consisting of polyurethanes and its copolymers, silicone and its copolymers, ethylene vinylacetate, thermoplastic elastomers, polyvinylchloride, polyolefins, cellulosics, polyamides, polytetrafluoroethylenes, polyesters, polycarbonates, polysulfones, acrylics, and acrylonitrile butadiene styrene copolymers, and, forming a tissue-exposed overlying outer polymer metering layer supported by said internal polymer layer, said outer polymer metering layer having a stable, uniform, predetermined thickness covering the underlying reservoir so that no portion of the reservoir is directly exposed to body fluids, and incorporating a distribution of an elutable component which, upon exposure to body fluids, elutes from said outer polymer metering layer to form a predetermined porous network capable of exposing said therapeutic agent in said reservoir in said internal polymer layer to said body fluid, said elutable component being selected from the group consisting of polyethylene oxide, polyethylene glycol, polyethylene oxide/polypropylene oxide copolymers, polyhydroxyethylmethacrylate, polyvinylpyrollidone, polyacrylamide and its copolymers, liposomes, albumin, dextran, proteins, peptides, polysaccharides, polylactides, polygalactides, polyanhydrides, polyorthoesters and their copolymers, and soluble cellulosics, wherein said reservoir defined by said internal polymer layer incorporates said therapeutic agent in a manner that permits substantially free outward release of said agent from said reservoir into said porous network of said outer polymer metering layer as said elutable component elates from said polymer metering layer, said predetermined thickness of said outer polymer layer and the concentration and particle size of said elutable component are selected to enable said outer polymer metering layer to meter the rate of outward migration of the therapeutic agent from the reservoir through the outer polymer metering layer, and said outer polymer metering layer and said internal polymer layer, in combination, enable prolonged controlled release, at said predetermined dosage level, from said exposed surface of said medical device to the tissue of said patient to inhibit adverse reaction of the patient to the prolonged presence of the body of said medical device in said patient.

Claim 2

A method for forming a medical device the function of which requires exposure to the tissue of a patient, comprising: forming an internal polymer layer defining a reservoir for a therapeutic agent selected from the group consisting of antithrombogenic agents, antiplatelet agents, prostaglandins, thrombolytic drugs, antiproliferative drugs, antirejection drugs, antimicrobial drugs, growth factors, and anticalcifying agents, that inhibits adverse reaction to the presence of the device, the internal polymer layer comprising a polymer selected from the group consisting of polyurethanes and its copolymers, silicone and its copolymers, ethylene vinylacetate, thermoplastic elastomers, polyvinylchloride, polyolefins, cellulosics, polyamides, polytetrafluoroethylenes, polyesters, polycarbonates, polysulfones, acrylics, and acrylonitrile butadiene styrene copolymers, and, forming a tissue-exposed overlying outer polymer metering layer supported by said internal polymer layer, said outer polymer metering layer having a stable, uniform, predetermined thickness covering the underlying reservoir so that no portion of the reservoir is directly exposed to body fluids, and incorporating a distribution of an elutable component which, upon exposure to body fluids, elutes from said outer polymer metering layer to form a predetermined porous network capable of exposing said therapeutic agent in said reservoir in said internal polymer layer to said body fluid, said elutable component being selected from the group consisting of polyethylene oxide, polyethylene glycol, polyethylene oxide/polypropylene oxide copolymers, polyhydroxyethylmethacrylate, polyvinylpyrollidone, polyacrylamide and its copolymers, liposomes, albumin, dextran, proteins, peptides, polysaccharides, polylactides, polygalactides, polyanhydrides, polyorthoesters and their copolymers, and soluble cellulosics, wherein said reservoir defined by said internal polymer layer incorporates said therapeutic agent in a manner that permits substantially free outward release of said agent from said reservoir into said porous network of said outer polymer metering layer as said elutable component elates from said polymer metering layer, said predetermined thickness of said outer polymer layer and the concentration and particle size of said elutable component are selected to enable said outer polymer metering layer to meter the rate of outward migration of the therapeutic agent from the reservoir through the outer polymer metering layer, and said outer polymer metering layer and said internal polymer layer, in combination, enable prolonged controlled release, at said predetermined dosage level, from said exposed surface of said medical device to the tissue of said patient to inhibit adverse reaction of the patient to the prolonged presence of the body of said medical device in said patient.

Claim 8

The method of any one of claims 4 or 5 further comprising: selecting the size and concentration of said elutable component to produce a continuous network in said polymer.