Method of Drying Bioabsorbable Coating Over Stents

• US 20100323093A1
• Filed: 04/23/2010
• Published: 12/23/2010
• Est. Priority Date: 12/28/2000
• Status: Active Grant

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Hossainy, Syed F.A., Chen, Yung-Ming, Pacetti, Stephen D., Van Sciver, Jason
• Granted Patent: US 8,632,845 B2
• Time in Patent Office: Days
• US Class Current: 427/2.25
• 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 2/86 Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• 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: A61F 2310/00389 The prosthesis being coated or covered with a particular material
• CPC Class Codes: A61L 2420/02 Methods for coating medical devices
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 31/148 Materials at least partially resorbable by the body
• CPC Class Codes: B05D 1/38 with intermediate treatment intermediate treatment per se B05D3/00
• CPC Class Codes: B05D 3/0254 After-treatment
• CPC Class Codes: B05D 3/0473 for heating, e.g. vapour heating
• CPC Class Codes: B29C 65/10 using hot gases (e.g. combustion gases) or flames coming in contact with at least one of the parts to be joined
• CPC Class Codes: B29C 65/76 Making non-permanent or releasable joints
• CPC Class Codes: B29K 2067/046 PLA, i.e. polylactic acid or polylactide
• CPC Class Codes: B29K 2105/258 Tubular
• CPC Class Codes: B29L 2031/7534 Cardiovascular protheses

Abstract

Various embodiments of methods for coating stents are described herein. Applying a composition including polymer component and solvent to a stent substrate followed by exposing the polymer component to a temperature equal to or greater than a Tg of the polymer component is disclosed. Repeating the applying and exposing one or more times to form a coating with the result that the solvent content of the coating after the final exposing step is at a level suitable for a finished stent is further disclosed.

Claims

1. A method of coating a stent, comprising:

applying a composition to a stent substrate, the composition including a polymer component and a solvent;

exposing the polymer component to a temperature equal to or greater than a Tg of the polymer component, wherein the exposing removes solvent from the applied composition; and

repeating the applying and exposing one or more times to form a coating, wherein the solvent content of the coating after the final exposing step is at a level suitable for a finished stent.

2. The method of claim 1, wherein the Tg of the polymer component is greater than room temperature.

3. The method of claim 1, wherein the Tg of the polymer component is greater than human body temperature.

4. The method of claim 1, wherein the stent substrate is a bioabsorbable polymer.

5. The method of claim 1, wherein the polymer component is a bioabsorbable polymer.

6. The method of claim 1, wherein the solvent content of the coating in the finished stent is less than 2 wt %.

7. The method of claim 1, wherein the exposing comprises blowing a heated gas on the polymer component to heat the polymer component to a temperature equal to or greater than a Tg of the polymer component.

8. The method of claim 1, wherein the stent substrate is PLLA and the polymer component is PDLA, the composition and the coating further comprising a therapeutic agent.

9. The method of claim 1, wherein each exposing comprises a different time and different temperature, all temperatures being at a temperature equal to or greater than a Tg of the polymer component.

10. A method of coating a stent, comprising:

applying a composition to a stent substrate, the composition including a polymer component and a solvent;

thermally treating the applied composition, wherein the thermal treatment removes solvent from the applied composition; and

repeating the applying and thermal treatment one or more times to form a coating,

wherein a duration of each of the thermal treatments is less than 60 s.

11. The method of claim 10, wherein the stent substrate is a bioabsorbable polymer.

12. The method of claim 10, wherein the polymer component is a bioabsorbable polymer.

13. The method of claim 10, wherein the thermal treatment comprises blowing a heated gas on the stent.

14. The method of claim 10, wherein stent is not baked after the final repetition of the thermal treatment.

15. The method of claim 10, wherein the solvent content of the coating is reduced to less than 2 wt % by the thermal treatment.

16. The method of claim 10, wherein no additional thermal treatment of the stent is performed after the final repetition of the thermal treatment.

17. The method of claim 10, wherein the thermal treatment comprises exposing the polymer component to a temperature equal to or greater than a Tg of the polymer component.

18. The method of claim 10, wherein no additional thermal treatment involving exposure of the stent to a temperature greater than 40°

C. is performed or no additional thermal treatment involving exposure for greater than 60 s is performed on the stent.

19. A method of making a stent, comprising:

depositing a composition onto a stent substrate, the composition including a polymer component and a solvent;

blowing a heated gas onto the deposited composition, wherein the heated gas removes solvent from the deposited composition; and

repeating the applying and thermal treatment one or more times to form a coating, wherein the coating comprises less than 2 wt % solvent.

20. The method of claim 19, wherein further processing steps do not include baking the stent to remove residual solvent.

21. The method of claim 19, wherein the heated gas is nitrogen to create an inert blanket.

22. The method of claim 19, wherein the heated gas is applied in a pulsed sequence.