Drug delivery system and method of manufacturing thereof

Abstract

A method of modifying the surface of a medical device to release a drug in a controlled way by providing a barrier layer on the surface of one or more drug coatings. The barrier layer consists of modified drug material converted to a barrier layer by irradiation by an accelerated neutral beam derived from an accelerated gas cluster ion beam. Also medical devices formed thereby.

What is claimed is: 
     
         1 . A medical device having a surface adapted for delivering one or more drugs, comprising: and one or more drug coating layers on the surface of the device, at least one of the drug coating layers having at least one barrier layer adapted for controlling a rate of flow of material across the at least one barrier layer, and further wherein the at least one barrier layer consists of drug modified by Neutral Beam irradiation. 
     
     
         2 . The medical device of  claim 1 , wherein the at least one barrier layer:
 controls a release rate of drugs;   controls an elution rate of drugs; or   controls an inward diffusion rate of a fluid into at least one of the one or more drug coating layers.   
     
     
         3 . The medical device of  claim 1 , wherein at least one drug coating layer of the one or more drug coating layers contains a first quantity of a first drug, said first drug overlaid by a first barrier layer comprising modified first drug, said first barrier layer overlaid by a second quantity of a second drug, said second drug overlaid by a second barrier layer comprising modified second drug. 
     
     
         4 . The medical device of  claim 3 , wherein:
 the first drug and the second drug are the same drug or different drugs; and   the first barrier layer and the second barrier layer are constructed to control a temporal release profile of the first and second drugs.   
     
     
         5 . The medical device of  claim 1 , wherein the controlled flow rate is:
 a drug elution rate;   a drug release rate; or   a fluid diffusion rate.   
     
     
         6 . The medical device of  claim 1 , wherein the medical device is any of:
 a vascular stent;   a coronary stent;   an artificial joint prosthesis;   an artificial joint prosthesis component; or   a coronary pacemaker.   
     
     
         7 . The medical device of  claim 1 , wherein the at least one barrier layer comprising modified drug is selected from the group consisting of:
 cross-linked drug molecules;   a densified drug;   a carbonized organic drug material;   a polymerized drug; or   a denaturized drug; and   combinations thereof.   
     
     
         8 . The medical device of  claim 1 , wherein the at least one barrier layer comprises a biologically active material.