Medical devices for delivering a therapeutic agent and method of preparation

• US 20080275544A1
• Filed: 10/30/2007
• Published: 11/06/2008
• Est. Priority Date: 04/26/1993
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Berg, Eric P., Tuch, Ronald J., Wolff, Rodney G., Dror, Michael
• Granted Patent: US 7,811,317 B2
• Time in Patent Office: Days
• US Class Current: 623/1.42
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2/88 the wire-like elements formed as helical or spiral coils forming a net-like or mesh-like structure A61F2/90
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 2300/236 Glycosaminoglycans, e.g. heparin, hyaluronic acid, chondroitin
• CPC Class Codes: A61L 2300/42 Anti-thrombotic agents, anticoagulants, anti-platelet agents
• CPC Class Codes: A61L 2300/432 Inhibitors, antagonists A61L2300/402 - A61L2300/43 take precedence
• CPC Class Codes: A61L 29/041 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 29/044 Proteins; Polypeptides; Degradation products thereof
• CPC Class Codes: A61L 29/06 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 29/145 Hydrogels or hydrocolloids
• CPC Class Codes: A61L 29/146 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 29/16 Biologically active materials, e.g. therapeutic substances A61L29/048 takes precedence
• CPC Class Codes: A61L 31/042 Polysaccharides
• CPC Class Codes: A61L 31/043 Proteins; Polypeptides; Degradation products thereof
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/06 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/145 : Hydrogels or hydrocolloids
• CPC Class Codes: A61L 31/146 : Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 31/16 : Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence

Abstract

A method for making an intravascular stent by applying to the body of a stent a solution which includes a solvent, a polymer dissolved in the solvent and a therapeutic substance dispersed in the solvent and then evaporating the solvent. The inclusion of a polymer in intimate contact with a drug on the stent allows the drug to be retained on the stent during expansion of the stent and also controls the administration of drug following implantation. The adhesion of the coating and the rate at which the drug is delivered can be controlled by the selection of an appropriate bioabsorbable or biostable polymer and the ratio of drug to polymer in the solution. By this method, drugs such as dexamethasone can be applied to a stent, retained on a stent during expansion of the stent and elute at a controlled rate.

Claims

1. A method for delivery of a therapeutic substance to the interior of a body lumen using a radially expandable intravascular stent, the stent being made by applying to the stent a mixture of a solvent, a polymer dissolved in the solvent and a therapeutic substance dispersed in the solvent, evaporating the solvent to provide a coat of therapeutic substance and polymer on the stent, and repeating the applying and evaporating until a plurality of coats of therapeutic substance and polymer are on the stent, said method for delivery comprising the steps of:

introducing the stent and the plurality of coats of therapeutic substance and polymer transluminally into a selected portion of the body lumen; and

radially expanding the stent and the plurality of coats of therapeutic substance and polymer into contact with the body lumen such that the plurality of coats of therapeutic substance and polymer are retained on the stent.

2. The method according to claim 1, wherein the stent has a metal surface.

3. The method according to claim 1, wherein the mixture is applied to the stent by spraying.

4. The method according to claim 1, wherein the ratio of therapeutic substance to polymer in the mixture is in the range of about 10:

1 to 1;

100.

5. A method for delivery of a therapeutic substance to the interior of a body lumen, comprising the steps of:

introducing a stent having a plurality of coats of therapeutic substance and polymer on a surface thereof transluminally into a selected portion of the body lumen; and

radially expanding the stent and the plurality of coats of therapeutic substance and polymer into contact with the body lumen such that the plurality of coats of therapeutic substance and polymer are retained on the surface,

wherein the stent is made by the process of;

(a) providing a generally cylindrical, balloon expandable metal stent body having a surface;

(b) spraying onto the stent body a solution which includes a solvent, a polymer dissolved in the solvent and a therapeutic substance dispersed in the solvent;

(c) evaporating the solvent to provide a coat of therapeutic substance and polymer on the surface; and

(d) repeating steps (b) and (c) until a plurality of coats of therapeutic substance and polymer are on the surface.

6. The method according to claim 5, wherein the ratio of therapeutic substance to polymer in the mixture is in the range of about 10:

1 to 1;

100.