Method Of Producing A Tube For Use In The Formation Of A Stent, And Such Tube

• US 20150230946A1
• Filed: 09/24/2013
• Published: 08/20/2015
• Est. Priority Date: 09/24/2012
• Status: Active Grant

• Current Assignee: Arterius Limited
• Original Assignee: Arterius Limited
• Inventors: Kelly, Adrian, Thompson, Glen P., Caton-Rose, Phil, Al-Lamee, Kadem, Coates, Philip D.
• Granted Patent: US 10,299,944 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61F 2/04 Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts A61F2/18, A61F2/20 take precedence; devices, other than stent-grafts, providing patency to, or preventing collapsing of, tubular structures of the body other than stent-grafts, e.g. stents A61F2/82; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95
• 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 2210/0004 bioabsorbable
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/152 the inner surfaces thereof
• CPC Class Codes: B29C 55/22 of tubes B29C61/08 takes precedence
• CPC Class Codes: B29C 55/24 radial
• CPC Class Codes: B29C 55/26 biaxial
• CPC Class Codes: B29C 55/30 Drawing through a die pultrusion B29C70/52
• CPC Class Codes: B29C 70/52 Pultrusion, i.e. forming and compressing by continuously pulling through a die
• CPC Class Codes: B29D 23/00 Producing tubular articles B29D24/00 takes precedence
• CPC Class Codes: B29K 2995/006 Bio-degradable, e.g. bioabsorbable, bioresorbable or bioerodible
• CPC Class Codes: B29L 2023/007 Medical tubes other than catheters catheters B29L2031/7542

Abstract

Bioresorbable polymeric tubes suitable for use in a stent have been produced by a using a die drawing technique, comprising: —deforming an orientable, thermoplastic polymer tubing (4) in the solid phase by drawing it over a mandrel (1) and/or through a die (3), where the mandrel (1) has a lead end and an exit end and the die (3) has an entry side and an exit side, wherein a drawing mechanism applies a drawing tension to the tubing (4) from the exit end of the mandrel (1) and/or the exit side of the die (3), said tension being insufficient to cause tensile failure of the tubing but sufficient to deform the tubing, thereby drawing the tubing over the mandrel (1) and/or through the die (3) in the solid phase to induce uniaxial or biaxial orientation of the polymer; and —collecting the deformed tubing from the exit end of the mandrel (1) and/or the exit side of the die (3).

Claims

1-58. -58. (canceled)

59. A method of producing a tube for use in the formation of a stent, said method comprising:

deforming an orientable, thermoplastic polymer tubing in the solid phase by drawing it over a mandrel and/or through a die, where the mandrel has a lead end and an exit end and the die has an entry side and an exit side, wherein;

a drawing mechanism applies a drawing tension to the tubing from the exit end of the mandrel and/or the exit side of the die, said tension being insufficient to cause tensile failure of the tubing but sufficient to deform the tubing, thereby drawing the tubing over the mandrel and/or through the die in the solid phase to induce uniaxial or biaxial orientation of the polymer; and

collecting the deformed tubing from the exit end of the mandrel and/or the exit side of the die.

60. A method according to claim 59, wherein the orientable, thermoplastic polymer tubing is at a temperature above the glass transition temperature and below the melting temperature of the thermoplastic polymer.

61. A method according to claim 59, wherein the bulk cross-sectional area of the polymeric tubing is reduced by drawing said tubing over the mandrel and/or through the die.

62. A method according to claim 59, wherein the diameter of the mandrel at its widest point is from 0.01 to 15 mm.

63. A method according to claim 59, wherein the mandrel is an expanding cone mandrel.

64. A method according to claim 59, wherein the angle of inclination of the taper is from 5 to 60 degrees, optionally wherein the angle of inclination of the taper is from 20 to 40 degrees.

65. A method according to claim 59, wherein the entry side of the die has a diameter from 0.4 to 8.0 mm and/or the exit side of the die has a diameter from 1.0 to 15 mm, optionally wherein the entry side of the die has a diameter from 2.0 to 4.0 mm.

66. A method according to claim 59, wherein the die is selected from:

a conical die;

a converging (reducing) die;

a diverging (expanding) die; and

a parallel (sizing) die, optionally wherein the die is a diverging die.

67. A method according to claim 59, wherein the semi angle of the die entry and/or exit is from 0 to 50 degrees, optionally wherein the semi angle is from 20 to 40 degrees.

68. A method according to claim 59, wherein the ratio of the die entry or exit angle and the angle of inclination of the mandrel taper is in the range of 1:

1 to 10;

1, optionally in the range of 1;

1 to 5;

1.

69. A method according to claim 59, wherein the inner hoop draw ratio is at least 1.5 and/or wherein the axial draw ratio is from 1.5:

1 to 15;

1, optionally from 2.5;

1 and 4;

1.

70. A method according to claim 59, wherein the ratio of the axial draw ratio to the inner hoop draw ratio is in the range of 0.5:

1 to 10;

1.

71. A method according to claim 59, further comprising the step of extruding the thermostatic polymeric tubing from an upstream extruder prior to the deformation step.

72. A method according to claim 59, wherein the cooling of the orientable, thermoplastic polymer tubing starts while in contact with the die and/or mandrel or immediately after said tubing has been drawn over the mandrel and/or through the die.

73. A method according to claim 59, wherein the orientable, thermoplastic polymer tubing for use in said method has an inner diameter from 0.5 mm to 4.0 mm, and an outer diameter from 0.9 mm and 15 mm and/or wherein the orientable, thermoplastic polymer tubing for use in said method has a wall thickness of 0.1 mm to 1.0 mm.

74. A method according to claim 59 further comprising preparing a stent from a tubing subjected to the process of said claim.

75. A tube for use in a stent comprising a polymeric material produced by the method of claim 59 wherein the tube has been subjected to orientation by die drawing with a mandrel and/or a die.

76. A tube for use in a stent comprising a polymeric material according to claim 75 having a wall thickness that is from 75 microns to 150 microns, optionally wherein the tube has a tensile modulus from 2,500 to 6,000 MPa and a tensile yield strength from 90 to 600 MPa.

77. The tube of claim 75, wherein the polymeric material is bioresorbable and the breakdown products are biocompatible.

78. The tube of claim 75, wherein the polymeric material is oriented in the axial and radial directions of the tube.

79. The tube of claim 75, wherein the ultimate tensile strength is from 120 to 800 Mpa and/or wherein the tube has an inner diameter from 0.5 to 4.0 mm and an outer diameter from 1.5 mm to 15 mm.

80. The tube of claim 75 wherein the polymeric material is:

albumin;

collagen;

hyaluronic acid and derivatives thereof;

sodium alginate and derivatives thereof;

chitosan and derivatives thereof;

gelatine;

starch;

cellulose polymers;

casein;

dextran and derivatives thereof;

polysaccharides;

fibrinogen;

copolymers prepared from caprolactone and/or lactide and/or glycolide and/or polyethylene glycol, poly(valerolactone), polydioxanone and lactide;

copolymers of lactide and 1,4-dioxane-2-one;

poly(hydroxybutyrate);

poly(hydroxyvalerate);

poly(hydroxybutyrate-co-hydroxyvalerate) copolymers;

poly(alkylcarbonate);

poly(orthoesters);

tyrosine based polycarbonates and polyarylates;

poly(ethylene terephthalate);

poly(anhydrides);

poly(ester-amides);

polyphosphazenes;

poly(amino acids);

poly-L-lactic acid (PLLA);

poly-D,L-lactic acid (PDLLA);

polyglycolic acid (PGA);

copolymers of polylactic acid;

polyglycolic acid (PLGA);

polycaprolactone;

poly (4-hydroxybutyrate) (P4HB);

polydioxanone;

poly (trimethylene carbonate);

poly (hydroxybutyrate-hydroxyvalerate);

polyorthoester;

poly(ester amides);

poly (ortho esters);

polyanhydrides;

poly (anhydride-co-imide);

poly (propylene fumarate);

pseudo poly (amino acid);

poly (alkyl cyanoacrylates);

polyphosphazenes; and

polyphosphoester, optionally wherein the polymeric material is Poly (L-lactide), Poly (D,L-lactide), Poly(glycolide) or copolymers and/or blends thereof.

81. The tube of claim 75 wherein the polymeric material has a crystallinity from 5 to 90%, preferably from 30 to 70%.

82. A stent formed from the tubing of claim 75, optionally wherein the stent is a vascular stent, a ureteral stent, a urethral stent, a duodenal stent, a colonic stent or a biliary stent, optionally wherein the stent is a coronary stent or a peripheral, a cardiothoracic, or a neuro vascular stent, optionally wherein the stent is expandable.