Stent with polymer coating containing amorphous rapamycin

Abstract

A coated coronary stent, comprising: a stainless steel sent framework coated with a primer layer of Parylene C; and a rapamycin-polymer coating having substantially uniform thickness disposed on the stent framework, wherein the rapamycin-polymer coating comprises polybutyl methacrylate (PBMA), polyethylene-co-vinyl acetate (PEVA) and rapamycin, wherein substantially all of the rapamycin in the coating is in amorphous form and substantially uniformly dispersed within the rapamycin-polymer coating.

1 . A coated coronary stent, comprising:
 a stainless steel sent framework coated with a primer layer of Parylene C; and   a rapamycin-polymer coating having substantially uniform thickness disposed on the stent framework, wherein the rapamycin-polymer coating comprises polybutyl methacrylate (PBMA), polyethylene-co-vinyl acetate (PEVA) and rapamycin, wherein substantially all of the rapamycin in the coating is in amorphous form and substantially uniformly dispersed within the rapamycin-polymer coating.   
   
   
       2 . The stent of  claim 1 , wherein PBMA, PEVA and rapamycin are present in a ratio of about 1:1:1. 
   
   
       3 . The stent of  claim 1 , wherein rapamycin is in the form of particles having an average diameter from 2 nm to 500 nm. 
   
   
       4 . The stent of  claim 1 , wherein said coating has a thickness of about 1 to about 30 microns. 
   
   
       5 . The stent of  claim 1 , wherein said coating is substantially free of solvent residue. 
   
   
       6 . The stent of  claim 1 , wherein the rapamycin-polymer coating is sintered in dense carbon dioxide at a temperature of about 50 C to about 60 C and a pressure below 1000 psig, whereby bulk properties and adhesion of the coating to said stent are improved without altering the quality of the rapamycin, PBMA or PEVA. 
   
   
       7 . The stent of  claim 1 , wherein said rapamycin-polymer coating covers substantially the entire surface of said stent framework. 
   
   
       8 . The stent of  claim 1 , wherein said rapamycin-polymer coating is substantially free of aggregated particles. 
   
   
       9 . A stent coated with a polymer and rapamycin, comprising:
 a stainless steel stent framework coated with a primer layer of Parylene C; and   a rapamycin-polymer coating disposed on the stent framework, wherein the rapamycin-polymer coating comprises PBMA, PEVA; and rapamycin substantially uniformly dispersed within the rapamycin-polymer coating, wherein substantially all of rapamycin in the coating is in amorphous form, wherein disposing said coating is carried out by a spray coating process whereby rapamycin spray particles are formed by rapid expansion of a supercritical or near critical fluid mixture, and said rapamycin spray particles and said stent framework are oppositely charged so that said spray particles are electrostatically attracted to said stent framework.   
   
   
       10 . The stent of  claim 9 , wherein said spray coating process is carried out under RESS conditions. 
   
   
       11 . The stent of  claim 10 , wherein said supercritical or near critical fluid mixture comprises PBMA, PEVA and rapamycin dissolved in dimethylether, chlorofluorocarbon, hydrofluorocarbon, carbon dioxide or mixtures thereof. 
   
   
       12 . The stent of  claim 10 , wherein PBMA, PEVA and rapamycin are co-deposited from a single mixture. 
   
   
       13 . The stent of  claim 10 , wherein PBMA, PEVA and rapamycin are separately deposited on the stent.