Solid-state drawing method for preparing a surgical suture or a biodegradable stent

Patent metadata

Field	Value
Publication number	US-10722388-B2
Application number	US-201715716620-A
Country	US
Kind code	B2
Filing date	Sep 27, 2017
Priority date	Jun 1, 2017
Publication date	Jul 28, 2020
Grant date	Jul 28, 2020

Abstract

A solid-state drawing method for preparing a surgical suture or a biodegradable stent having improved flexibility and mechanical strength. The method for preparing a biodegradable stent includes (a) providing a biodegradable filament that comprises a material which is biodegradable; (b) solid-state drawing the biodegradable filament to provide a drawn biodegradable filament; (c) shaping the drawn biodegradable filament to provide a shaped biodegradable filament; and (d) annealing the shaped biodegradable filament to provide the biodegradable stent, wherein the biodegradable filament has a draw ratio that ranges from 1.1 to 5.0; and wherein the draw ratio is calculated by Equation 1 below:

Draw ratio=( L SSD /L O ) 2 ,
where L O is length of the biodegradable filament before the solid-state drawing, and L SSD is the length of the biodegradable filament after the solid-state drawing.

First claim

What is claimed is:

1. A method for preparing a biodegradable stent, comprising:
(a) providing a biodegradable filament that comprises a material which is biodegradable, that comprises polylactic acid, and that has a glass transition temperature and a melting temperature;
(b) solid-state drawing the biodegradable filament to provide a drawn biodegradable filament, the biodegradable filament having a draw ratio that ranges from 1.1 to 5.0, that is calculated by Equation 1 below:
Draw ratio=( L SSD /L O ) 2 ,

where L O is length of the biodegradable filament before the solid-state drawing, and L SSD is the length of the biodegradable filament after the solid-state drawing;
(c) shaping the drawn biodegradable filament to provide a shaped biodegradable filament; and
(d) annealing the shaped biodegradable filament to provide the biodegradable stent,
wherein the solid-state drawing is performed by:
fixing ends of the biodegradable filament between a rotatable releasing structure and a rotatable winding structure; and
rotating the rotatable releasing structure and the rotatable winding structure in the same direction, such that the rotatable winding structure is rotated at a rotational velocity that is higher than that of the rotatable releasing structure and provides a rotational velocity ratio of the rotatable winding structure to the rotatable releasing structure that ranges from 1.01 to 3.0, and
wherein the solid-state drawing is performed by heat-treating the biodegradable filament in a heat treatment zone present between the rotatable releasing structure and the rotatable winding structure at a heat-treating temperature ranging between the glass transition temperature and the melting temperature of the biodegradable filament by heat-treating with air maintained at the heat-treating temperature which ranges from 120 to 150° C., and with a passage speed within the heat treatment zone that ranges from 4.3 to 4.5 mm/min.

2. The method for preparing a biodegradable stent according to claim 1 , wherein the biodegradable filament has a draw ratio ranging from 1.8 to 2.5.

3. A method for preparing a biodegradable stent, comprising: according to claim 2 , (a) providing a biodegradable filament that comprises a material which is biodegradable, that comprises polylactic acid, and that has a glass transition temperature and a melting temperature;
(b) solid-state drawing the biodegradable filament to provide a drawn biodegradable filament, the biodegradable filament having a draw ratio that ranges from 1.1 to 5.0, that is calculated by Equation 1 below:
Draw ratio=( L SSD /L O ) 2 ,

where L O is length of the biodegradable filament before the solid-state drawing, and L SSD is the length of the biodegradable filament after the solid-state drawing;
(c) shaping the drawn biodegradable filament to provide a shaped biodegradable filament; and
(d) annealing the shaped biodegradable filament to provide the biodegradable stent,
wherein the solid-state drawing is performed by:
fixing ends of the biodegradable filament between a rotatable releasing structure and a rotatable winding structure; and
rotating the rotatable releasing structure and the rotatable winding structure in the same direction, such that the rotatable winding structure is rotated at a rotational velocity that is higher than that of the rotatable releasing structure and provides a rotational velocity ratio of the rotatable winding structure to the rotatable releasing structure that ranges from 1.01 to 3.0, and
wherein the solid-state drawing is performed by heat-treating the biodegradable filament in a heat treatment zone present between the rotatable releasing structure and the rotatable winding structure at a heat-treating temperature ranging between the glass transition temperature and the melting temperature of the biodegradable filament by heat-treating with air maintained at the heat-treating temperature which ranges from 120 to 150° C., and with a passage speed within the heat treatment zone that ranges from 4.3 to 4.5 mm/min, and wherein the annealing is performed by heat treating with air maintained at a heat treating temperature ranging from 60 to 100° C. for a time period ranging from 30 to 180 minutes.

4. The method for preparing a biodegradable stent according to claim 3 , wherein the biodegradable filament has a draw ratio ranging from 1.8 to 2.5.

Assignees

• Korea Inst Sci & Tech

Inventors

• Kim Soo Hyun
• Jung Young Mee
• Im Seung Hyuk

Classifications

• D02G3/448

  Yarns or threads for use in medical applications (D02G3/449 takes precedence; surgical suture materials A61L17/00) · CPC title

• A61L31/148 Primary

  Materials at least partially resorbable by the body · CPC title

• A61L31/04

  Macromolecular materials · CPC title

• A61L17/12

  Homopolymers or copolymers of glycolic acid or lactic acid · CPC title

• A61L17/10 Primary

  containing macromolecular materials · CPC title