Post electron beam conditioning of polymeric medical devices

Patent metadata

Field	Value
Publication number	US-9566723-B2
Application number	US-201314139740-A
Country	US
Kind code	B2
Filing date	Dec 23, 2013
Priority date	Apr 21, 2010
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

Methods are disclosed for conditioning a polymeric stent after sterilization, and/or after crimping and before packaging, such that the properties of the polymeric stent fall within a narrower range of values. The stent is exposed to a controlled temperature at or above ambient for a period of time after radiation sterilization and/or after crimping and before sterilization. As a result, the polymeric stent properties, particularly radial strength and number-average molecular weight of the polymer of the polymeric stent, fall within a narrower range.

First claim

What is claimed is:

1. A method for conditioning a polymeric stent, the method comprising:
determining a specified value of the radial strength of a polymeric stent including a polymeric scaffolding to result from exposing the polymeric stent to a controlled temperature for a duration of time, wherein the specified value is 10% to 40% lower than an initial value of the radial strength of the polymeric stent;
exposing the polymeric stent to the controlled temperature of 30° C. to 40° C. for the duration of time of from 1 day to 20 days sufficient to reduce the radial strength of the polymeric stent to the specified value;
wherein the polymeric scaffolding is made of a polymer derived from reaction of monomers including L-lactide, and
wherein the polymeric stent has been crimped onto a delivery device, packaged, and sterilized prior to the exposure.

2. The method of claim 1 , wherein the polymeric scaffolding is formed from a polymeric tube that has been deformed by the application of stress, the deformation comprising radial expansion of the polymeric tube at a temperature greater than that of the glass transition temperature of the polymeric tube.

3. The method of claim 1 , wherein the polymeric scaffolding comprises a polymer selected from the group consisting of poly(L-lactide), poly(DL-lactide), poly(L-lactide-co-glycolide), and all combinations thereof in all proportions.

4. The method of claim 1 , wherein the scaffolding is made of a random, alternating, or block copolymer of two or more of the group of claim 3 .

5. The method of claim 1 , wherein the exposure temperature is not higher than 20° C. below the glass transition temperature of the polymeric scaffolding.

6. The method of claim 1 , wherein the duration of exposure is from about 8 hours to about 20 days and the exposure temperature is from about 32° C. to about 40° C.

7. The method of claim 1 , wherein the duration of exposure is from about 1 day to about 10 days.

8. The method of claim 1 , wherein the duration of exposure is from about 2 days to about 6 days.

9. The method of claim 1 , wherein the specified value is 10% to 20% lower than the initial value of the radial strength.

10. The method of claim 1 , wherein the exposure temperature is controlled to within ±3° C.

11. The method of claim 1 , wherein the specified value is a pseudo-steady state or plateau value.

12. The method of claim 1 , wherein the specified value is 20% to 30% lower than the initial value of the radial strength.

13. The method of claim 1 , wherein the specified value is 30% to 40% lower than the initial value of the radial strength.

Assignees

• Abbott Cardiovascular Systems Inc

Inventors

• Wang Yunbing
• Ma Xiao
• Tang Fuh-Wei
• Ding Ni

Classifications

• A61L2103/15

  Laboratory, medical or dentistry appliances, e.g. catheters or sharps · CPC title

• A61L2/087

  Particle radiation, e.g. electron-beam, alpha or beta radiation · CPC title

• A61L2103/05

  Living organisms or biological materials · CPC title

• A61L2202/21

  Human Necessities · mapped topic

• C08L67/04

  Polyesters derived from hydroxycarboxylic acids, e.g. lactones (C08L67/06 takes precedence) · CPC title