Ethylene-carboxyl copolymers as drug delivery matrices
A coated stent is provided including a coating composed of one or more co-polymers of ethylene with carboxylic acid wherein the carboxylic acid co-monomer content is 5-50 wt %.
1. A method of coating an implantable medical device, comprising:
adding a copolymer of an ethylene comonomer with a carboxylic acid comonmer to a solvent system to form a composition;
mixing a therapeutic drug with the copolymer composition to allow the drug uniformly dispersed in the copolymer composition, wherein the drug concentration is 5% to 20% by weight;
applying the composition to an implantable medical device; and
allowing the solvent system to evaporate;
wherein the carboxylic acid comonomer content is 5%-50 wt %.
2. The method of claim 1 , wherein the carboxylic acid comonomer is selected from a group consisting of acrylic acid, methacrylic acid, maleic acid, itaconic acid, and esters thereof.
3. The method of claim 1 , wherein adding the copolymer to the solvent system further comprises neutralizing the copolymer in a volatile or a non-volatile base and dispersing the copolymer in water and/or a co-solvent.
4. The method of claim 1 , wherein the solvent system comprises toluene.
5. The method of claim 4 , wherein the solvent system further comprises a chlorinated solvent and a lower alcohol.
6. The method of claim 1 , wherein the carboxylic acid co-monomer has a content in the copolymer 15% to 40% by weight.
7. The method of claim 1 , wherein the co-polymer is ethylene acrylic acid.
8. The method of claim 1 , wherein the device comprises a stent.