Cation exchange materials for dialysis systems

Patent metadata

Field	Value
Publication number	US-11331597-B2
Application number	US-201916532161-A
Country	US
Kind code	B2
Filing date	Aug 5, 2019
Priority date	Aug 5, 2019
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

A sorbent cartridge device includes an ion-exchange material containing zirconium phosphate and no more than about 0.1 mg of leachable phosphate ions per about 1 g of the ion-exchange material. In one example, the cartridge also includes a phosphate-adsorbing material containing zirconium oxide. In this example, the weight ratio between zirconium phosphate and zirconium oxide in the cartridge is from about 10:1 to about 40:1. The zirconium phosphate may be alkaline zirconium phosphate prepared by a process including the following steps: (i) drying acid zirconium phosphate to obtain a dry acid zirconium phosphate; (ii) combining the dry acid zirconium phosphate with an aqueous solution to obtain an aqueous slurry; and (iii) combining the slurry with an alkali hydroxide to obtain the alkaline zirconium phosphate. During step (ii), any free phosphate ions in the dry acid zirconium phosphate leach out into the aqueous phase of the slurry.

First claim

What is claimed is:

1. A sorbent cartridge device, comprising:
an ion-exchange material comprising zirconium phosphate,
wherein the device comprises less than about 0.1 mg of leachable phosphate ions per about 1 g of the ion-exchange material, and
weight ratio of P to Zr in the ion-exchange material is from about 1.5:1 to about 2:1.

2. The device of claim 1 , comprising from about 0.01 mg to about 0.03 mg of leachable phosphate ions per about 1 g of the ion-exchange material.

3. The device of claim 1 , further comprising a phosphate-adsorbing material comprising a zirconium oxide.

4. The device of claim 3 , wherein the weight ratio between the zirconium phosphate and the zirconium oxide in the device is from about 10:1 to about 40:1.

5. The device of claim 3 , comprising a homogenous mixture of the zirconium phosphate and the zirconium oxide.

6. The device of claim 3 , comprising a layer of the zirconium phosphate and a layer of the zirconium oxide.

7. The device of claim 1 , further comprising a urea-decomposing material.

8. The device of claim 7 , wherein the urea-decomposing material is a urease enzyme.

9. The device of claim 7 , further comprising alumina.

10. The device of claim 1 , wherein the zirconium phosphate comprises an alkaline zirconium phosphate.

11. The device of claim 10 , wherein the alkaline zirconium phosphate is prepared by a process comprising:
drying an acid zirconium phosphate to obtain a dry acid zirconium phosphate;
combining the dry acid zirconium phosphate with an aqueous solution to obtain an aqueous slurry of the acid zirconium phosphate; and
combining the slurry with an alkali hydroxide to obtain the alkaline zirconium phosphate.

12. The device of claim 1 , comprising:
sodium content of about 60 mg to about 100 mg per about 1 g of the ion-exchange material;
ammonia or ammonium adsorption capacity of about 15 mg to about 20 mg per about 1 g of the ion-exchange material.

13. A dialysis system comprising:
a dialysate generation machine;
a pump adapted to move fluid through the dialysate generation machine; and
a sorbent cartridge device fluidically connected to the dialysate generation machine, wherein
the device comprises an ion-exchange material comprising zirconium phosphate and less than about 0.1 mg of leachable phosphate ions per about 1 g of the ion-exchange material, wherein weight ratio of P to Zr in the ion-exchange material is from about 1.5:1 to about 2:1.

14. The system of claim 13 , wherein the device comprises from about 0.01 mg to about 0.03 mg of leachable phosphate ions per about 1 g of the ion-exchange material.

15. The system of claim 13 , wherein the device comprises a phosphate-adsorbing material comprising a zirconium oxide.

16. The system of claim 15 , wherein the weight ratio between the zirconium phosphate and the zirconium oxide in the device is from about 10:1 to about 40:1.

17. The system of claim 13 , wherein the device comprises a urea-decomposing material.

18. The system of claim 13 , wherein the zirconium phosphate comprises an alkaline zirconium phosphate.

19. A method of removing one or more substances from a spent dialysis solution, the method comprising passing the spent dialysis solution through a sorbent cartridge device comprising an ion-exchange material comprising zirconium phosphate,
wherein the device comprises less than about 0.1 mg of leachable phosphate ions per about 1 g of the ion-exchange material and wherein weight ratio of P to Zr in the ion-exchange material is from about 1.5:1 to about 2:1.

20. The method of claim 19 , the one or more substances comprise ammonia or ammonium.

Assignees

• Fresenius Medical Care Holdings Inc

Inventors

• Barrett Spencer
• Kaufman Colin

Classifications

• B01J47/00 Primary

  Ion-exchange processes in general; Apparatus therefor (ion-exchange chromatography processes or apparatus B01D15/08) · CPC title

• B01J39/12

  Compounds containing phosphorus · CPC title

• B01J39/10

  Oxides or hydroxides · CPC title

• A61M1/1696 Primary

  with dialysate regeneration · CPC title

• A61M1/1672

  using membrane filters, e.g. for sterilising the dialysate · CPC title