Coatings for medical devices

Abstract

The present invention is directed to improved coatings and coating methods for medical devices.

We claim: 
     
         1 . A coated medical device, comprising:
 at least one metal surface, at least a portion of which is coated with a metal oxide nanolayer;   at least a portion of the surface of the metal oxide nanolayer is coated with covalently bonded organosilane groups substituted with at least one reactive organic substituent; and   an optional active pharmaceutical agent bonded to or complexed with at least a portion of the reactive organic substituents.   
     
     
         2 . The coated medical device of  claim 1 , wherein the medical device is selected from the group consisting of an intra-cranial stent, a carotid stent, a cardiac stent, a peripheral vascular stent, a vascular graft, a cardiac valve, and an intra-vascular device. 
     
     
         3 . The coated medicals device of  claim 1 , wherein the at least one metal surface comprises a metal or alloy selected from the group consisting of biomedical grade titanium, iron, nickel, magnesium, cobalt, and chromium. 
     
     
         4 . The coated medical device of  claim 1 , wherein at least 90% of the metal surface is coated with the metal oxide nanolayer. 
     
     
         5 . The coated medical device of  claim 1 , wherein the metal oxide nanolayer comprises a metal oxide selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide, hafnium oxide, zirconium oxide, zinc oxide, tin oxide, strontium oxide, ytterbium oxide, Zn 1-x Sn x O y , ZTO, SrTiO 3 , SrCO 3 ), and combinations thereof. 
     
     
         6 . The coated medical device of  claim 1 , wherein the metal oxide nanolayer has a thickness of less than about 30 nm. 
     
     
         7 . The coated medical device of  claim 1 , wherein the organosilane groups have the general formula:
   (X—R) n Si—Y 4-n  or
     Y 3 Si—R—Z—R—SiY 3  
   wherein n is an integer from 1-3,   each X is independently H, substituted or unsubstituted vinyl, halo, hydroxyl, substituted or unsubstituted amino, acryloxy, methacryloxy, —SH, or substituted or unsubstituted ureido, each R is independently alkyl aryl, or arylalkyl,   Z is disulfide or tetrasulfide, and   Each Y is independently halo or alkoxy.   
     
     
         8 . The coated medical device of  claim 1 , in which the active pharmaceutical agent is not present. 
     
     
         9 . The coated medical device of  claim 1 , in which the active pharmaceutical agent is present. 
     
     
         10 . The coated medical device of  claim 9 , wherein the active pharmaceutical agent is selected from the group consisting of hepatocyte growth factor, anti-thrombotic agents, antiplatelet agent and combinations thereof. 
     
     
         11 . The coated medical device of  claim 1 , wherein the surface tension of the organosilane coated surface ranges from about 0-30°.