Coated medical device and method of coating such a device
A medical device such as a stent ( 10 ) or medical balloon ( 40 ) is functionalised prior to coating with a bioactive material ( 54 ), specifically by acidification or basification of the contact surface or surfaces ( 50 ) of the medical device. Functionalisation with subsequent coating of bioactive agent directly onto the functionalised surface provides a significantly more consistent and reliable coating of bioactive agent on a medical device without requiring containment or time release devices.
1. A method of coating a medical device having a structure for implantation or disposition inside a patient, the structure including at least one surface for coating, the method including the steps of:
functionalizing the at least one surface of the structure by subjecting the at least one surface to acidification by a carboxylic acid, to form at least one functionalized surface; and
applying a material coating directly to the at least one functionalized surface of the medical device, the coating comprising a bioactive material to be released from the medical device, the coating being a conjugate base or including a conjugate base component of the carboxylic acid,
wherein the functionalizing does not form a polymer matrix on the at least one surface.
2. A method according to claim 1 , wherein the step of functionalizing the at least one surface causes an increase in acidic polar components at the at least one surface.
3. A method according to claim 1 , wherein the coating:
a) consists of or is principally of bioactive material;
b) is or includes a therapeutic substance;
c) is or includes an anti proliferative bioactive substance; or
d) is or includes paclitaxel.
4. A method according to claim 1 , wherein the coating is free of at least one of:
a) containment elements;
b) binding agents;
c) time control release agents; and
d) polymer or other matrix material.
5. A method according to claim 1 , wherein the functionalized surface is substantially impervious to the material coating.
6. A method according to claim 1 , wherein the entirety of the at least one surface is functionalized.
7. A method according to claim 1 , wherein the step of functionalizing the at least one surface does not remove or altering oxide on the at least one surface.
8. A method according to claim 1 , further including the step of atomically cleaning the at least one surface prior to functionalization, said atomic cleaning being without removal of oxide on the at least one surface.
9. A method according to claim 1 , further including the step of cleaning the at least one surface with an alcohol prior to functionalization.
10. A method according to claim 1 , wherein the at least one surface is functionalized by treatment for around five minutes.
11. A method according to claim 1 , wherein the at least one surface is functionalized by treatment with one or more of: citric acid, acetic acid, lactic acid, alginic acid, adipic acid and conjugates and derivatives thereof.
12. A method according to claim 1 , wherein the at least one functionalized surface includes a dispersal facilitator including a C—C component.
13. A method according to claim 1 , wherein the medical device is or includes:
a) a stent or balloon;
b) a stent and wherein the structure is made of nickel titanium alloy; or
c) a balloon and the coating includes an excipient.
14. A medical device including: a structure for implantation or disposition inside a patient, the structure including at least one surface for coating;
wherein the at least one surface is functionalized by a carboxylic acid, so as to be a functionalized surface; and a material coating disposed directly on the at least one functionalized surface of the medical device, the coating comprising a bioactive material to be released from the medical device, the coating being a conjugate base or including a conjugate base component of the carboxylic acid, and
wherein the functionalizing does not form a polymer matrix on the at least one surface.
15. A medical device according to claim 12 , wherein the at least one functionalized surface has an increased acidic polar composition compared to a remainder of the structure of the medical device.
16. A medical device according to claim 12 , wherein the coating:
a) consists of or is principally of bioactive material;
b) is or includes a therapeutic substance;
c) is or includes an anti proliferative bioactive substance; or
d) is or includes paclitaxel.
17. A medical device according to claim 12 , wherein the coating is free of at least one of:
a) containment elements;
b) binding agents;
c) time control release agents; and
d) polymer or other matrix material.