Fluid extraction or filtration device, associated materials and methods

• US 8,585,682 B2
• Filed: 02/09/2009
• Issued: 11/19/2013
• Est. Priority Date: 02/09/2008
• Status: Active Grant

• Current Assignee: Renephra Limited
• Original Assignee: Renephra Limited
• Inventors: Mitra, Sandip, Brenchley, Paul Ernest Charles, Ulijn, Rein Vincent
• Primary Examiner(s): Ho, (Jackie) Tan-Uyen T.
• Assistant Examiner(s): BRYANT, ERIC C
• Application Number:
  US12/866,882
• Publication Number:
  US 20100318070A1
• Time in Patent Office: 1,744 Days
• Field of Search: None
• US Class Current: 604/540
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150091 by electricity
• CPC Class Codes: A61B 5/150358 Strips for collecting blood, e.g. absorbent optical reagent test strips G01N21/8483; chemical reagent test strips G01N33/4875, G01N33/52
• CPC Class Codes: A61B 5/150969 Low-profile devices which resemble patches or plasters, e.g. also allowing collection of blood samples for testing
• CPC Class Codes: A61B 5/150984 Microneedles or microblades
• CPC Class Codes: A61B 5/151 Devices specially adapted for taking samples of capillary blood, e.g. by lancets , needles or blades
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61F 13/15203 Properties of the article, e.g. stiffness or absorbency chemical aspects A61L15/00
• CPC Class Codes: A61M 1/14 Dialysis systems; Artificial kidneys; Blood oxygenators semi-permeable membranes characterised by the material, manufacturing processes therefor B01D71/00; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis
• CPC Class Codes: A61M 1/3679 by absorption A61M1/3675 takes precedence
• CPC Class Codes: A61M 1/3687 Chemical treatment A61M1/3675 takes precedence
• CPC Class Codes: A61M 1/71 Suction drainage systems containers therefor A61M1/60, A61M1/64; negative pressure wound therapy systems A61M1/90
• CPC Class Codes: A61M 2037/003 having a lumen
• CPC Class Codes: A61M 2037/0061 Methods for using microneedles
• CPC Class Codes: A61M 37/0015 by using microneedles

Abstract

A fluid extraction or filtration device for removing fluid from a body, the device comprising an array of microneedles for contacting fluid in said body and an absorbent gel matrix in fluid communication with said array of microneedles. There is further provided a combined fluid extraction and sampling device and methods employing the device(s), for example in determining the level of a target species in a sample of fluid, transdermal dialysis and renal replacement therapy. There is further provided an absorbent gel matrix for use in the treatment of uraemia and a haemodialysis filter comprising an absorbent gel matrix. Use of such a matrix is described in the context of methods including haemodialysis, transdermal dialysis and gastrointestinal dialysis.

Claims

1. A method employing a device comprising an array of microneedles for contacting fluid in a body of a patient and a dry absorbent gel matrix in fluid communication with said array of microneedles, wherein a first region of the array of microneedles is arranged for contacting the fluid and a second region of the array of microneedles is arranged for contacting the dry absorbent get matrix, separate from the first region, the method comprising

contacting said fluid with said first region of the array of microneedles so as to establish an osmotic gradient between the fluid and the dry absorbent gel matrix such that said fluid flows from said body to said dry absorbent gel matrix via said microneedles.

2. The method of claim 1 wherein said fluid comprises a target species, said patient is in need of having said target species removed from said fluid and said dry absorbent target species are retained in said gel matrix.

3. The method of claim 2 wherein the method comprises transdermal purification wherein said patient is in need of having said fluid purified by removal of said target species.

4. The method of claim 2 wherein the method comprises transdermal filtration and wherein said patient is in need of having said target species filtered from said fluid.

5. The method of claim 1 comprising transdermal dialysis wherein said patient is in need of dialysis.

6. The method of claim 1 wherein said patient is in need of renal replacement therapy.

7. The method of claim 1 wherein the method is used for the treatment of uremia;

and wherein said patient suffers from uremia; and

wherein said fluid that flows from said body to said dry absorbent gel matrix via said array of microneedles contains one or more uremic toxin.

8. The method of claim 7 wherein said method treats salt and water overload in said patient.

9. A fluid extraction or filtration device adapted for removing fluid from a body of a patient, comprising:

an array of microneedles for contacting fluid in said body, comprising a first region configured for contacting said fluid, and a separate second region, and

an absorbent gel matrix in fluid communication with said array of microneedles, in contact said separate second region of said array of microneedles so as to establish an osmotic gradient between the fluid and the absorbent gel matrix;

wherein said absorbent gel matrix is dry prior to contacting the fluid.

10. The fluid extraction or filtration device according to claim 9, wherein the absorbent gel matrix is configured to retain said fluid after its removal from the body.

11. The fluid extraction or filtration device according to claim 9, wherein said fluid contains one or more toxins, and wherein the body is a human or animal body and the device is arranged to effect the selective removal of one or more said toxins from said human or animal body fluid.

12. The fluid extraction or filtration device according to claim 9, wherein the fluid is interstitial tissue fluid or at least one component thereof.

13. The fluid extraction or filtration device according to claim 12, wherein said at least one component of interstitial fluid is selected from the group consisting of water, a uremic toxin, a metabolic product, a salt and an ion.

14. The fluid extraction or filtration device according to claim 9, wherein at least some of the microneedles comprise a hollow section and define side and/or end pores to provide access to the hollow section of said microneedles.

15. The fluid extraction or filtration device according to claim 14, wherein said hollow section of the microneedles is substantially empty of liquid prior to using the device to remove fluid from said body.

16. The fluid extraction or filtration device according to claim 9, wherein the microneedle array comprises up to 900 microneedles.

17. The fluid extraction or filtration device according to claim 9, wherein at least some of the needles in said microneedle array possess a height of up to 500 μ

m.

18. The fluid extraction or filtration device according to claim 9, wherein at least some of the needles in said microneedle array possess a maximum outer cross-sectional diameter of 1 μ

m to 200 μ

m.

19. The fluid extraction or filtration device according to claim 9, wherein the absorbent gel matrix exhibits an ability to entrap water of up to 90% w/w.

20. The fluid extraction or filtration device according to claim 9, wherein the absorbent gel matrix exhibits an ability to absorb up to 30 times its own weight of water.

21. The fluid extraction or filtration device according to claim 9, wherein the absorbent gel matrix comprises polyethylene glycol and/or derivatives thereof.

22. The fluid extraction or filtration device according to claim 9, wherein the absorbent gel matrix comprises a polyethylene glycol/polyacrylate copolymer.

23. The fluid extraction or filtration device according to claim 22, wherein the device exhibits an ability to absorb up to 50 grams of fluid or water per gram of matrix material.