Stent drug delivery system

Abstract

Expandable intraluminal stents are provided as well their method of manufacture. These stents are made of metal, the metal characterized by a desired porosity, with a drug compressed into the pores of the stent. The stents are formed by subjecting one or more powdered metals in a die cavity to a pressure treatment followed by a heat treatment. The metal may be cast directly in a stent-like form or cast into sheets or tubes from which the inventive stents are produced. The so-formed porous metal stent is then loaded with one or more drugs.

What is claimed is as follows:  
     
         1 . A method of forming a stent comprising the steps of: 
 providing a first powdered metal;    providing a second powdered metal, the first powdered metal and second powdered metal having a different composition or different physical properties or both;    treating the first and second powdered metals to form a stent-preform;    forming a stent from the stent preform.    
     
     
         2 . The method of    claim 1    wherein the stent preform is a sheet.  
     
     
         3 . The method of    claim 2    wherein the sheet is rolled into tubular form during the forming step.  
     
     
         4 . The method of    claim 3   , the sheet having opposing edges, wherein an edge is secured to an opposing edge during the forming step.  
     
     
         5 . The method of    claim 1    where the preform is laser cut during the forming step.  
     
     
         6 . The method of    claim 1    wherein the stent preform is a tube.  
     
     
         7 . The method of    claim 1    wherein the treating step includes subjecting the first and second powdered metals to high pressure to form the preform.  
     
     
         8 . The method of    claim 1    wherein the treating step includes subjecting the first and second powdered metals to high pressure to form a compact and sintering the compact to form the preform.  
     
     
         9 . The method of    claim 1    wherein the treating step includes sintering the first and second powdered metals to form the preform.  
     
     
         10 . The method of    claim 1    wherein: 
 the treating step includes subjecting the first and second powdered metals to high pressure to form a compact and sintering the compact to form a preform selected from the group consisting of sheets and tubes and either  
 rolling the preform in the case where the preform is a sheet to form the stent or  
 laser cutting the preform in the case where the preform is a tube to form the stent.  
 
     
     
         11 . The method of    claim 1    wherein the first and second metals are characterized by different average particle size.  
     
     
         12 . The method of    claim 1    wherein the first and second metals are elementally different metals.  
     
     
         13 . A method of forming a stent comprising the steps of: 
 providing a tube formed from a powdered metal;    cutting the tube to a desired shape using a laser.    
     
     
         14 . The method of    claim 13    wherein the powdered metal has been sintered.  
     
     
         15 . The method of    claim 13    wherein the powdered metal has been subjected to high pressure to form a compact and the compact sintered.  
     
     
         16 . The method of    claim 15    wherein the tube is formed from at least two powdered metals, a first powdered metal and a second powdered metal, the first and second powdered metals having a different composition or different physical properties or both.  
     
     
         17 . The method of    claim 13    wherein the tube is formed from at least two powdered metals, a first powdered metal and a second powdered metal, the first and second powdered metals having a different composition or different physical properties or both.  
     
     
         18 . A method of forming a stent comprising the steps of: 
 providing a sheet formed from at least one powdered metal;    rolling the sheet to form a tubular stent.    
     
     
         19 . The method of    claim 18    wherein the sheet has been sintered.  
     
     
         20 . The method of    claim 18    wherein the powdered metal has been subjected to high pressure to form a compact and the compact sintered.  
     
     
         21 . The method of    claim 20    wherein the sheet is formed from at least two powdered metals, a first powdered metal and a second powdered metal, the first and second powdered metals having a different composition or different physical properties or both. which are characterized  
     
     
         22 . The method of    claim 18    wherein the sheet is formed from at least two powdered metals, a first powdered metal and a second powdered metal, the first and second powdered metals having a different composition or different physical properties or both.