METHOD AND APPARATUS FOR LIMITING DIAFILTRATE WASTE

• US 20110100909A1
• Filed: 08/19/2008
• Published: 05/05/2011
• Est. Priority Date: 08/23/2007
• Status: Active Grant

• Current Assignee: Albutec GmbH
• Original Assignee: Albutec GmbH
• Inventors: Stange, Katrin
• Granted Patent: US 9,302,038 B2
• Time in Patent Office: Days
• US Class Current: 210/636
• CPC Class Codes: A61M 1/1696 with dialysate regeneration
• CPC Class Codes: A61M 1/3431 upstream of the filter
• CPC Class Codes: A61M 1/3434 with pre-dilution and post-dilution
• CPC Class Codes: A61M 1/3437 downstream of the filter, e.g. post-dilution with filtrate
• CPC Class Codes: A61M 1/3441 Substitution rate control as a function of the ultrafiltration rate
• CPC Class Codes: A61M 1/3468 using treated filtrate as substitution fluid
• CPC Class Codes: A61M 1/3472 with treatment of the filtrate
• CPC Class Codes: A61M 1/3486 Biological, chemical treatment, e.g. chemical precipitation; treatment by absorbents

Abstract

The present invention describes a process and a device for saving diafiltrate by partial regeneration using adsorbers. An object of the invention is to decrease the requirement of dialysate and/or substituate in the depletion of a substance of class X by means of special microstructured adsorption/filtration devices. An object of the invention is also to enable control of the concentration of a substance group X by hemodialysis and/or hemofiltration, such that by partial recirculation of the diafiltrate in the regeneration circuit, the net throughput of diafiltrate can be kept lower. The process serves for saving dialysate and/or substituate solution in control of the concentration of a substance group X in a complex biological liquid compartment, wherein the net throughput of dialysate and/or substituate is minimized by some of the diafiltrate being regenerated by an internal regeneration cycle (RKL) which is able to deplete substrates or products (substance group Y) of the substance group X in the biological liquid compartment.

Claims

1-24. -24. (canceled)

25. A dialysis process for the removal of at least one undesired substance from a biological fluid comprising:

supplying an unfiltered biological fluid comprising a concentration of a substance X and a concentration of a substance Y that is a precursor or metabolite of the substance X to a first side of a separation apparatus in which the first side is separated from a second side of the separation apparatus by a porous membrane;

providing a dialysate fluid on the second side of the separation apparatus;

the porous membrane having pores of a preselected size through which the substance X and the substance Y of the unfiltered biological fluid can pass;

whereby the substance X and the substance Y pass through the pores to the second side and enter the dialysate fluid, forming a diafiltrate fluid on the second side, the passing of the substance X from the unfiltered biological fluid producing a filtered biological fluid;

removing the filtered biological fluid from the first side of the separation apparatus;

removing the diafiltrate fluid from the second side of the separation apparatus;

separating the diafiltrate fluid into a first fluid and second fluid;

discarding the first fluid as a net-diafiltrate fluid;

supplying the second fluid to a regeneration circuit having a substance Y removal component;

contacting the second fluid with the substance Y removal component;

whereby at least a portion of the substance Y is removed from the second fluid to produce a regenerate flow fluid having a reduced concentration of the substance Y;

producing a replenishment dialysate fluid comprised of regenerate flow fluid and fresh dialysate fluid; and

introducing the replenishment dialysate fluid to the second side of the separation apparatus;

whereby, the inclusion of the regenerate flow fluid in the replenishment dialysate fluid effects a reduction in a total amount of dialysate fluid employed in the dialysis process.

28. The process any one of claims 25 to 27 wherein the substance X is urea, and the substance Y is selected from the group consisting of amino acids, peptides, and proteins, with the proviso that the amino acid is not glutamine, and the substance Y removal component comprises a charcoal-based adsorbent.

29. The process of claim 28 wherein the substance Y removal component further comprises a plurality of channels sized in a range of 10 nanometers to 100 micrometers that provide a short diffusion distance for the substance Y to reach the charcoal-based adsorbent.

30. The process of any one of claims 25 to 27 wherein the substance X is urea, the substance Y is ammonia, and the substance Y removal component is free of urease and comprises a zirconium phosphate adsorbent.

31. The process any one of claims 25 and 27 wherein the dialysate fluid comprises a bicarbonate solution.

32. The process of claim 31 wherein the substance Y removal component comprises adsorbents including zirconium phosphate, and the removal of at least a portion of the substance Y from the second fluid occurs at a pH greater than 7.2.

33. The process of any one of claims 25 to 27 wherein the substance X is ammonia, the substance Y is glutamine, and the substance Y removal component comprises a charcoal-based adsorbent.

34. The process any one of claims 25 to 27 wherein the substance X is NO, the substance Y is arginine, and the substance Y removal component comprises a charcoal-based adsorbent.

35. The process of any one of claims 25 to 27 wherein the substance X is tumor necrosis factor, the substance Y is interleukin 1, and the substance Y removal component comprises a filter having adsorption capacity for interleukin 1.

36. The process of claim 35 wherein the substance Y removal component further comprises a filter made from a material selected from the group consisting of polysulfone, polyamide, polymethylmethacrylate, and polyacrylonitrile.

37. The process of any one of claims 25 and 27 wherein the replenishment dialysate fluid has a flow rate less than or equal to 500 ml/min.

38. The process of any one of any one of claims 25 and 27 wherein the replenishment dialysate fluid has a flow rate less than or equal to 300 ml/min.

39. The process of any one of any one of claims 25 and 27 wherein the replenishment dialysate fluid has a flow rate less than or equal to 100 ml/min.

43. The process of any one of claims 25 to 27 wherein the second fluid has a flow rate through the regeneration circuit that is greater than 5 ml/min.

44. The process of any one of claims 25 to 27 wherein the second fluid has a flow rate greater than 50 ml/min.

45. The process of any one of claims 25 to 27 wherein the second fluid has a flow rate greater than 100 ml/min.

46. The process any one of claims 25 to 27 wherein the porous membrane of the separation apparatus has a pore size in the range of 5,000 to 500,000 Daltons.

26. A filtration process for the removal of at least one undesired substance from a biological fluid comprising:

supplying an unfiltered biological fluid comprising a concentration of a substance X and a concentration of a substance Y that is a precursor or metabolite of the substance X to a first side of a separation apparatus in which the first side is separated from a second side of the separation apparatus by a porous membrane;

the porous membrane having pores of a preselected size through which the substance X and the substance Y and a fluid portion of the unfiltered biological fluid can pass;

whereby the substance X, the substance Y, and the fluid portion of the unfiltered biological fluid pass through the pores to the second side, forming a diafiltrate fluid on the second side of the separation apparatus;

whereby the passing of the substance X from the unfiltered biological fluid produces a filtered biological fluid;

removing the filtered biological fluid from the first side of the separation apparatus;

removing the diafiltrate fluid from the second side of the separation apparatus;

separating the diafiltrate fluid into a first fluid and second fluid;

discarding the first fluid as a net-diafiltrate fluid;

supplying the second fluid to a regeneration circuit having a substance Y removal component;

contacting the second fluid with the substance Y removal component;

whereby at least a portion of the substance Y is removed from the second fluid to produce a regenerate flow fluid having a reduced concentration of the substance Y;

producing a replenishment substitute fluid comprised of the regenerate flow fluid and a substitute fluid;

combining the replenishment substitute fluid with one of the unfiltered biological fluid, the filtered biological fluid, and a combination of the unfiltered and filtered biological fluid;

whereby, the inclusion of the regenerate flow fluid in the replenishment substitute fluid effects a reduction in a total amount of substitute fluid employed in the filtration process.

40. The process of any one of any one of claims 26 and 27 wherein the replenishment substitute fluid has a flow rate less than or equal to 500 ml/min.

41. The process of any one of claims 26 and 27 wherein the replenishment substitute fluid has a flow rate less than or equal to 300 ml/min.

42. The process of any one of claims 26 and 27 wherein the replenishment substitute fluid has a flow rate less than or equal to 100 ml/min.

27. A diafiltration process for the removal of at least one undesired substance from a biological fluid comprising:

supplying an unfiltered biological fluid comprising a concentration of a substance X and a concentration of a substance Y that is a precursor or metabolite of the substance X to a first side of a separation apparatus in which the first side is separated from a second side of the separation apparatus by a porous membrane;

providing a dialysate fluid on the second side of the separation apparatus;

the porous membrane having pores of a preselected size through which the substance X and the substance Y of the unfiltered biological fluid can pass;

whereby the substance X and the substance Y pass through the pores to the second side and enter the dialysate fluid, forming a diafiltrate fluid on the second side, the passing of the substance X from the unfiltered biological fluid producing a filtered biological fluid;

removing the filtered biological fluid from the first side of the separation apparatus;

removing the diafiltrate fluid from the second side of the separation apparatus;

separating the diafiltrate fluid into a first fluid and second fluid;

discarding the first fluid as a net-diafiltrate fluid;

supplying the second fluid to a regeneration circuit having a substance Y removal component and contacting the second fluid with the substance Y removal component;

whereby at least a portion of the substance Y is removed from the second fluid to produce a regenerate flow fluid having a reduced concentration of the substance Y;

producing a replenishment dialysate fluid comprised of a first portion of the regenerate flow fluid and fresh dialysate fluid;

producing a replenishment substitute fluid comprised of a second portion of the regenerate flow fluid and a substitute fluid;

introducing the replenishment dialysate fluid to the second side of the separation apparatus;

combining the replenishment substitute fluid with one of the unfiltered biological fluid, the filtered biological fluid, and a combination of the unfiltered and filtered biological fluid;

whereby, the inclusion of the regenerate flow fluid in the replenishment dialysate fluid effects a reduction in a total amount of dialysate fluid employed in the diafiltration process, and

the inclusion of the regenerate flow fluid in the replenishment substitute fluid effects a reduction in a total amount of substitute fluid employed in the diafiltration process.

47. A device for filtering a biological fluid, comprising:

a separation apparatus having a porous membrane that separates the separation apparatus into first and second sides wherein a diafiltrate stream is produced on the second side, the diafiltrate stream comprising a fluid, a substance X and a substance Y, the substance X and the substance Y passing through the porous membrane from a biological fluid located on the first side of the porous membrane;

a first fluid line in communication with the first side of the separation apparatus for the removal of a filtered biological fluid;

a second fluid line in communication with the separation apparatus and a regeneration circuit downstream of the separation apparatus through which the diafiltrate stream flows, the second fluid line having a first branch and a second branch, wherein a first portion of the diafiltrate stream is drawn through the first branch and discarded as a net diafiltrate and the second branch of the second fluid line carries a second portion of the diafiltrate stream;

the second branch communicating with a regeneration circuit having a substance Y removing component, the second branch directing the second portion into the regeneration circuit where the second portion of the diafiltrate steam contacts the substance Y removing component, effecting a reduction of the concentration of substance Y and forming a regenerate flow stream;

a regenerate flow line for carrying the regenerate flow stream away from the regeneration circuit;

a supply source of fresh fluid in communication with the regenerate flow line, wherein a fresh fluid from the supply source of fresh fluid combines with the regenerate flow stream to produce a replenishment fluid;

a replenishment fluid flow line for carrying the replenishment fluid to a preselected entrance point on the diafiltrate device.

48. The device of claim 47 wherein the fresh fluid is a dialysate fluid.

49. The device of claim 47 wherein the fresh fluid is a substitute fluid.

50. The device of any one of claims 47 to 49 wherein the substance Y removal component comprises activated charcoal.

51. The device of any one of claims 47 to 49 wherein the substance Y removal component comprises a membrane filter.

52. The device of any one of claims 47 to 49 wherein the substance Y removal component comprises a charcoal material that passes glutamine.

53. The device of any one of claims 47 to 49 wherein the substance Y is selected from the group consisting of peptides and proteins;

the porous membrane of the separation apparatus having pores with a pore size of 70,000 Daltons, and the substance Y removal component is a charcoal filter having a plurality of channels sized in the range of 10 nanometers to 100 nanometers.

54. The device of any one of claims 47 to 49 wherein the porous membrane of the separation apparatus allows arginine to pass from the biological fluid on the first side of the separation apparatus to the second side of the separation apparatus, and the substance Y removal component is a charcoal-based adsorbent.

55. The device of any one of claims 47 to 49 wherein the porous membrane of the separation apparatus allows the passage of Interleukin 1 from the unfiltered biological fluid on the first side of the separation apparatus to the second side of the separation apparatus and the substance Y removal component is a charcoal filter having a plurality of channels sized in the range of 10 nanometers to 100 nanometers.