Multi-layer cannula structure

• US 4,994,047 A
• Filed: 05/06/1988
• Issued: 02/19/1991
• Est. Priority Date: 05/06/1988
• Status: Expired due to Term

• Current Assignee: Cardinal Health Switzerland 515 GmbH (Cardinal Health, Inc.)
• Original Assignee: Menlo Care, Inc. (Johnson & Johnson)
• Inventors: Thomas, Joseph R., Walker, Jack M.
• Primary Examiner(s): Yasko, John D.
• Assistant Examiner(s): Gutowski, Anthony M.
• Application Number:
  US07/191,007
• Time in Patent Office: 1,019 Days
• Field of Search: 604/21, 604/27, 604/48, 604/54, 604/96, 604/264-266, 604/270, 604/275, 604/280, 604/282
• US Class Current: 604/264
• CPC Class Codes: A61L 29/06 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61M 2025/0057 Catheters delivering medicament other than through a conventional lumen, e.g. porous walls or hydrogel coatings
• CPC Class Codes: A61M 2025/0064 which become stiffer or softer when heated
• CPC Class Codes: A61M 25/0045 multi-layered, e.g. coated coating materials A61L29/08
• CPC Class Codes: A61M 25/0054 with regions for increasing flexibility
• CPC Class Codes: C08L 75/04 Polyurethanes

Abstract

A swellable cannula is formed of concentric inner and outer hydrophilic and substantially non-hydrophilic layer structures. The hydrophilic layer structure comprises at least 2/3rds of the cross-sectional area of the wall of the cannula. The substantially non-hydrophilic layer structure is either substantially water impermeable or allows water to pass through at a controlled rate. The substantially non-hydrophilic layer structure may also control the diffusion of medicaments. The cannula has controlled softenability and swellability characteristics.

Claims

1. A swelling multilayer cannula having proximal and distal end portions and a wall defining an inner lumen, comprising:

(a) a hydrophilic layer structure having one or more hydrophilic layers having respective outer and inner surfaces and being formulated of a hydrophilic material characterized in that it increases in volume more than 1.3;

1 upon contact with an aqueous medium at 37°

C., said hydrophilic layer structure comprising at least 2/3rds of the cross-sectional area of said wall, said inner lumen swelling such that its cross-sectional area increases more than 20% upon contact of said hydrophilic layer structure with said aqueous medium at 37°

C.; and

(b) a substantially non-hydrophilic layer structure having one or more substantially non-hydrophilic layers having respective outer and inner surfaces and being formulated of a substantially non-hydrophilic material, an outer or inner surface of each of said hydrophilic layers being bonded to a corresponding inner or outer surface of at least one of said substantially non-hydrophilic layers, said bonded hydrophilic and substantially non-hydrophilic layers being of a construction such that they remain bonded to one another following swelling of said lumen such that its cross-sectional area increases more than 20% upon contact of said hydrophilic layer structure with said aqueous medium at 37°

C.

2. A cannula as set forth in claim 1, wherein an innermost of said hydrophilic and substantially non-hydrophilic layers is a first of said substantially non-hydrophilic layers and defines said lumen and wherein a first of said hydrophilic layers has its inner surface bonded to the outer surface of said first substantially non-hydrophilic layer.

3. A cannula as set forth in claim 2, further including, in said lumen:

at least one partition separating said lumen into at least two generally coextensive channels.

4. A cannula as set forth in claim 1, wherein said first substantially non-hydrophilic layer extends from a proximal end portion of said cannula but stops short of said distal end portion of said cannula.

5. A cannula as set forth in claim 1, wherein an innermost of said hydrophilic and substantially non-hydrophilic layer is a first of said hydrophilic layers and defines said lumen and wherein a first of said non-hydrophilic layers has its inner surface bonded to the outer surface of said first hydrophilic layer.

6. A cannula as set forth in claim 5, wherein said first substantially non-hydrophilic layer controls the diffusion rate of water or medicaments from said first hydrophilic layer to said outer surface of said first substantially non-hydrophilic layer.

7. A cannula as set forth in claim 1, wherein at least a first substantially non-hydrophilic layer of said substantially non-hydrophilic layer structure includes controlling means for controlling the lengthwise expansion of said cannula as it swells.

8. A cannula as set forth in claim 7, wherein said controlling means comprises a plurality of fibers oriented lengthwise and located in said first substantially non-hydrophilic layer.

9. A cannula as set forth in claim 7, wherein said controlling means comprises residual axial stress in said first substantially non-hydrophilic layer.

10. A cannula as set forth in claim 7, wherein said controlling means controls said lengthwise expansion to be no more than 5% when an outer diameter of said wall increases 15%.

11. A cannula as set forth in claim 1, wherein said one substantially non-hydrophilic layer is formulated of a thermoplastic material.

12. A cannula as set forth in claim 1, wherein said one substantially non-hydrophilic layer is formulated of a polyurethane material.

13. A cannula as set forth in claim 1, wherein said one substantially non-hydrophilic layer is formulated of an elastomeric material.

14. A cannula as set forth in claim 1, wherein said one substantially non-hydrophilic layer has a softening ratio of more than 5:

1 on being raised from about 20°

C. to 37°

C.

15. A cannula as set forth in claim 1, wherein said one hydrophilic layer is formulated of a material having a 2.5% Secant modulus of less than 20,000 psi when hydrated at 37°

C.

16. A cannula as set forth in claim 1, wherein said cannula decreases in 2.5% Secant modulus more than 10:

1 upon exposure to an aqueous medium at 37°

C.

17. A cannula as set forth in claim 1, wherein said hydrophilic layer material of said cannula comprises:

(a) a first phase which comprises a substantially non-hydrophilic polymeric component; and

(b) a second phase which comprises a hydrophilic polymeric component;

said material (i) being capable of absorbing water to an extent that it softens with a softening ration of at least about 2;

1 and/or swells with a swelling ratio of at least about 1.3;

1; and

(ii) when substantially completely hydrated at 37°

C., having an energy to break of at least about 700 N-cm/cm³ and a 2.5% Secant modulus of less than about 7,000 N/cm².

18. A cannula as set forth in claim 1, wherein said material, when at 37°

C., has an energy to break of at least about 700 N-cm/cm³ and a 2.5% Secant modulus of less than about 7,000 N/cm².

19. A swelling multilayer cannula having proximal and distal end portions and a wall defining an inner lumen, comprising:

(a) a hydrophilic layer structure having one or more hydrophilic layers having respective outer and inner surfaces and being formulated of a hydrophilic material characterized in that it increases in volume more than 1.3;

1 upon contact with an aqueous medium at 37°

C., said hydrophilic layer structure comprising at least 1/2rds of the cross-sectional area of said wall, said inner lumen swelling such that its cross-sectional area increases more than 20% upon contact of said hydrophilic layer structure with said aqueous medium at 37°

C.;

(b) a substantially non-hydrophilic layer structure having one or more substantially non-hydrophilic layers having respective outer and inner surfaces and being formulated of a substantially non-hydrophilic material, an outer or inner surface of each of said hydrophilic layers being bonded to a corresponding inner or outer surface of at least one of said substantially non-hydrophilic layers, said bonded hydrophilic and substantially non-hydrophilic layers being of a construction such that they remain bonded to one another following swelling of said lumen such that its cross-sectional area increases more than 20% upon contact of said hydrophilic layer structure with said aqueous medium at 37°

C.; and

wherein an innermost of said hydrophilic and substantially non-hydrophilic layers is a first of said substantially hydrophilic layers and defines said lumen, wherein a first of said substantially non-hydrophilic layers has its inner surface bonded to the outer surface of said first substantially hydrophilic layer and wherein a second of said hydrophilic layers has its inner surface bonded to the outer surface of said first substantially non-hydrophilic layer.

20. A swelling multilayer cannula having proximal and distal end portions and a wall defining an inner lumen, comprising:

(a) a hydrophilic layer structure having one or more hydrophilic layers having respective outer and inner surfaces and being formulated of a hydrophilic material characterized in that it increases in volume more than 1.3;

1 upon contact with an aqueous medium at 37°

C., said hydrophilic layer structure comprising at least 2/3rds of the crosssectional area of said wall, said inner lumen swelling such that its cross-sectional area increases more than 20% upon contact of said hydrophilic layer structure with said aqueous medium at 37°

C.;

(b) a substantially non-hydrophilic layer structure having one or more substantially non-hydrophilic layers having respective outer and inner surfaces and being formulated of a substantially non-hydrophilic material, an outer or inner surface of each of said hydrophilic layers being bonded to a corresponding inner or outer surface of at least one of said substantially non-hydrophilic layers, said bonded hydrophilic and substantially non-hydrophilic layers being of a construction such that they remain bonded to one another following swelling of said lumen such that its crosssectional area increases more than 20% upon contact of said hydrophilic layer structure with said aqueous medium at 37°

C.;

an innermost of said hydrophilic and substantially non-hydrophilic layers being a first of said substantially non-hydrophilic layers and defining said lumen;

a first of said hydrophilic layers having its inner surface bonded to the outer surface of said first substantially non-hydrophilic layer; and

wherein said substantially non-hydrophilic layer structure includes a second substantially non-hydrophilic layer having its inner surface bonded to the outer surface of said first hydrophilic layer.

21. A cannula as set forth in claim 20, wherein a second of said hydrophilic layers has its inner surface bonded to the outer surface of said second substantially non-hydrophilic layer and wherein said substantially non-hydrophilic layer structure includes a third substantially non-hydrophilic layer having its inner surface bonded to the outer surface of said second hydrophilic layer.

22. A cannula as set forth in claim 21, wherein said first substantially non-hydrophilic layer controls the diffusion rate of water or medicaments between said first hydrophilic layer and said lumen, said third substantially non-hydrophilic layer controls the diffusion rate of water or medicaments between said second hydrophilic layer and the outer surface of said third substantially non-hydrophilic layer, and said second substantially non-hydrophilic layer substantially prevents the diffusion of water or medicaments between said first and second hydrophilic layers.

23. A cannula as set forth in claim 20, wherein said first substantially non-hydrophilic layer controls the diffusion rate of water or medicaments between said first hydrophilic layer and said lumen and wherein said second substantially non-hydrophilic layer controls the diffusion rate of water or medicaments between said first hydrophilic layer and the outer surface of said second substantially non-hydrophilic layer.