Gradient coated stent and method of fabrication

Abstract

The gradient coated stent 150 of the present invention provides a coated stent having a continuous coating 130 disposed on the stent elements. The continuous coating 130 includes a first coating component and a second coating component. The concentration of the first coating component varies continuously over at least part of the thickness of the continuous coating 130. The concentration of the second coating component can also vary over at least part of the thickness of the continuous coating 130. In one embodiment, the concentration of the first coating component decreases in the direction from the stent element towards the outer edge of the continuous coating 130 and the concentration of the second coating component increases in the direction from the stent element towards the outer edge of the continuous coating 130.

1 - 18 . (canceled) 
     
     
         19 : A method for coating a stent comprising:
 providing a first coating solution  270 ;   providing a second coating solution  272 ;   applying the first coating solution to the stent through an applicator  274 ; and   applying the second coating solution to the stent through the applicator  276 .   
     
     
         20 : The method of  claim 19  wherein applying the first coating solution to the stent through an applicator; and applying the second coating solution to the stent through the applicator comprises:
 mixing the first coating solution and the second coating solution to form a gradient mixture; and 
 applying the gradient mixture to the stent through the applicator. 
 
     
     
         21 : The method of  claim 20  wherein the first coating solution includes a first coating component, and mixing the first coating solution and the second coating solution to form a gradient mixture comprises mixing the first coating solution and the second coating solution to vary concentration of the first coating component in the gradient mixture with time. 
     
     
         22 : The method of  claim 21  wherein the concentration of the first coating component in the gradient mixture varies linearly with time. 
     
     
         23 : The method of  claim 21  wherein the concentration of the first coating component in the gradient mixture decreases with time. 
     
     
         24 : The method of  claim 21  wherein the second coating solution includes a second coating component, and mixing the first coating solution and the second coating solution to form a gradient mixture further comprises mixing the first coating solution and the second coating solution to vary concentration of the second coating component in the gradient mixture with time. 
     
     
         25 : The method of  claim 24  wherein the concentration of the first coating component in the gradient mixture decreases with time and the concentration of the second coating component in the gradient mixture increases with time. 
     
     
         26 : The method of  claim 21  wherein the first coating component is selected from the group consisting of drugs, therapeutic agents, polymers, bi-polymers, co-polymers, and combinations thereof. 
     
     
         27 : The method of  claim 19  wherein the first coating solution and the second coating solution are incompatible. 
     
     
         28 : The method of  claim 19  wherein applying the first coating solution to the stent through an applicator comprises applying the first coating solution to the stent through an applicator using an application method selected from a group consisting of spraying, ultrasonic spraying, pressure spraying, painting, wiping, rolling, printing, ink jet printing, and combinations thereof. 
     
     
         29 : A system for producing a coated stent comprising:
 means for mixing a first coating component with a first solvent to form a first coating solution;   means for mixing a second coating component with a second solvent to form a second coating solution;   means for mixing the first coating solution and the second coating solution to form a gradient mixture so that the ratio of the first coating solution to the second coating solution in the gradient mixture varies with time;   means for applying the gradient mixture to a stent.   
     
     
         30 : The system of  claim 29  wherein the means for mixing the first coating solution and the second coating solution to form a gradient mixture so that the ratio of the first coating solution to the second coating solution in the gradient mixture varies with time comprises means for mixing the first coating solution and the second coating solution so that concentration of the first coating component in the gradient mixture varies with time. 
     
     
         31 : The system of  claim 30  wherein the means for mixing the first coating solution and the second coating solution to form a gradient mixture so that the ratio of the first coating solution to the second coating solution in the gradient mixture varies with time comprises means for mixing the first coating solution and the second coating solution so that concentration of the second coating component in the gradient mixture varies with time. 
     
     
         32 : A method for coating a stent comprising:
 mixing a first coating component with a first solvent to form a first coating solution  280 ;   mixing a second coating component with a second solvent to form a second coating solution  282 ;   mixing the first coating solution and the second coating solution to form a gradient mixture so that the ratio of the first coating solution to the second coating solution in the gradient mixture varies with time  284 ;   applying the gradient mixture to the stent  286 .   
     
     
         33 : The method of  claim 32  wherein mixing the first coating solution and the second coating solution to form a gradient mixture so that the ratio of the first coating solution to the second coating solution in the gradient mixture varies with time comprises mixing the first coating solution and the second coating solution so that concentration of the first coating component in the gradient mixture varies with time. 
     
     
         34 : The method of  claim 33  wherein the concentration of the first coating component in the gradient mixture varies linearly with time. 
     
     
         35 : The method of  claim 33  wherein the concentration of the first coating component in the gradient mixture decreases with time. 
     
     
         36 : The method of  claim 33  wherein mixing the first coating solution and the second coating solution to form a gradient mixture so that the ratio of the first coating solution to the second coating solution in the gradient mixture varies with time comprises mixing the first coating solution and the second coating solution so that concentration of the second coating component in the gradient mixture varies with time. 
     
     
         37 : The method of  claim 36  wherein the concentration of the first coating component in the gradient mixture decreases with time and the concentration of the second coating component in the gradient mixture increases with time. 
     
     
         38 : The method of  claim 32  wherein the first coating component is selected from the group consisting of drugs, therapeutic agents, polymers, bi-polymers, co-polymers, and combinations thereof. 
     
     
         39 : The method of  claim 32  wherein at least one pair of materials selected from the group consisting of the first coating component, the first solvent, the second coating component, and the second solvent are incompatible. 
     
     
         40 : The method of  claim 32  applying the gradient mixture to the stent comprises applying the gradient mixture to the stent using an application method selected from the group consisting of spraying, ultrasonic spraying, pressure spraying, painting, wiping, rolling, printing, ink jet printing, and combinations thereof. 
     
     
         41 : A system for producing a coated stent comprising:
 means for mixing a first coating component with a first solvent to form a first coating solution;   means for mixing a second coating component with a second solvent to form a second coating solution;   means for mixing the first coating solution and the second coating solution to form a gradient mixture so that the ratio of the first coating solution to the second coating solution in the gradient mixture varies with time;   means for applying the gradient mixture to a stent.   
     
     
         42 : The system of  claim 41  wherein the means for mixing the first coating solution and the second coating solution to form a gradient mixture so that the ratio of the first coating solution to the second coating solution in the gradient mixture varies with time comprises means for mixing the first coating solution and the second coating solution so that concentration of the first coating component in the gradient mixture varies with time. 
     
     
         43 : The system of  claim 42  wherein the means for mixing the first coating solution and the second coating solution to form a gradient mixture so that the ratio of the first coating solution to the second coating solution in the gradient mixture varies with time comprises means for mixing the first coating solution and the second coating solution so that concentration of the second coating component in the gradient mixture varies with time.