Medical devices having adherent polymeric layers with depth-dependent properties

Abstract

According to one aspect of the invention, a method of forming a medical device is provided, which includes: (a) contacting a substrate with a solution that contains (i) one or more types of polymers, (ii) a solvent that contains one or more types of solvent species, and (iii) one or more optional agents, for example, one or more therapeutic agents, among others; and (b) removing the solvent from the solution, thereby forming a polymeric layer on the substrate. The composition of the solution is changed over the course of forming the polymeric layer. In another aspect of the invention, a medical device is provided, which includes a substrate and a polymeric layer over the substrate. The polymeric layer contains a copolymer that contains differing first and second monomers. The lower surface of the polymeric layer contacting the substrate has a surface concentration of the first monomer relative to the second monomer that is higher than that of the upper surface of the polymeric layer opposite the substrate.

1 - 21 . (canceled) 
     
     
         22 . A medical device comprising a substrate and a polymeric layer that comprises a copolymer disposed over the substrate, the copolymer comprising differing first and second monomers, wherein a first homopolymer of the first monomer adheres to the substrate better than a second homopolymer the second monomer, and wherein the lower surface of the polymeric layer contacting the substrate has a higher surface concentration of the first monomer relative to the second monomer than does the upper surface of the polymeric layer opposite the substrate. 
     
     
         23 . The medical device of  claim 22 , wherein the upper surface of the polymeric layer has a higher surface concentration of the second monomer relative to the first monomer. 
     
     
         24 . The medical device of  claim 22 , wherein the first monomer is isobutylene and the second monomer is styrene. 
     
     
         25 . The medical device of  claim 22 , wherein the copolymer is a block copolymer comprising a first polymer block comprising the first monomer and a second polymer block comprising the second monomer. 
     
     
         26 . The medical device of  claim 25 , wherein the first monomer is isobutylene and the second monomer is styrene. 
     
     
         27 . The medical device of  claim 22 , wherein the substrate is a metallic substrate. 
     
     
         28 . The medical device of  claim 22 , wherein the medical device is selected from a stent, a filter, a lead for a cardiac rhythm management (CRM) device, a sensor, a valve and an aneurism filler coil. 
     
     
         29 . The medical device of  claim 22 , wherein the medical device is a stent. 
     
     
         30 . The medical device of  claim 22 , wherein the layer further comprises a therapeutic agent. 
     
     
         31 . The medical device of  claim 30 , wherein the therapeutic agent is selected from anti-thrombotic agents, anti-proliferative agents, anti-inflammatory agents, anti-migratory agents, agents affecting extracellular matrix production and organization, antineoplastic agents, anti-mitotic agents, anesthetic agents, anti-coagulants, vascular cell growth promoters, vascular cell growth inhibitors, cholesterol-lowering agents, vasodilating agents, agents that interfere with endogenous vasoactive mechanisms, and combinations thereof. 
     
     
         32 . The medical device of  claim 23 , wherein the substrate is a metallic substrate. 
     
     
         33 . The medical device of  claim 23 , wherein the medical device is selected from a stent, a filter, a lead for a cardiac rhythm management (CRM) device, a sensor, a valve and an aneurism filler coil. 
     
     
         34 . The medical device of  claim 23 , wherein the medical device is a stent. 
     
     
         35 . The medical device of  claim 23 , wherein the layer further comprises a therapeutic agent. 
     
     
         36 . The medical device of  claim 35 , wherein the therapeutic agent is selected from anti-thrombotic agents, anti-proliferative agents, anti-inflammatory agents, anti-migratory agents, agents affecting extracellular matrix production and organization, antineoplastic agents, anti-mitotic agents, anesthetic agents, anti-coagulants, vascular cell growth promoters, vascular cell growth inhibitors, cholesterol-lowering agents, vasodilating agents, agents that interfere with endogenous vasoactive mechanisms, and combinations thereof. 
     
     
         37 . The medical device of  claim 25 , wherein the substrate is a metallic substrate. 
     
     
         38 . The medical device of  claim 25 , wherein the medical device is selected from a stent, a filter, a lead for a cardiac rhythm management (CRM) device, a sensor, a valve and an aneurism filler coil. 
     
     
         39 . The medical device of  claim 25 , wherein the medical device is a stent. 
     
     
         40 . The medical device of  claim 25 , wherein the layer further comprises a therapeutic agent. 
     
     
         41 . The medical device of  claim 40 , wherein the therapeutic agent is selected from anti-thrombotic agents, anti-proliferative agents, anti-inflammatory agents, anti-migratory agents, agents affecting extracellular matrix production and organization, antineoplastic agents, anti-mitotic agents, anesthetic agents, anti-coagulants, vascular cell growth promoters, vascular cell growth inhibitors, cholesterol-lowering agents, vasodilating agents, agents that interfere with endogenous vasoactive mechanisms, and combinations thereof.