Sorbent for a dialysis device

Abstract

There is provided a sorbent for removing metabolic waste products from a dialysis liquid, the sorbent comprising a layer of immobilized uremic toxin-treating enzyme particles intermixed with cation exchange particles.

1 . A fixed bed sorbent for removing metabolic waste products from a dialysis liquid, the sorbent comprising a primary layer of uremic toxin-treating enzyme particles covalently immobilized on a biocompatible material intermixed with cation exchange particles and anion exchange particles,
 wherein a pressure drop of the dialysis liquid across the primary layer is dependent on the size of said cation exchange particles;   wherein said uremic toxin-treating enzyme particles and said cation exchange particles are, when in use, in direct contact with the dialysis liquid; and   wherein the anion exchange particles and cation exchange particles are selected to create pH buffering conditions when in direct contact with the dialysis liquid.   
     
     
         2 . The fixed bed sorbent as claimed in  claim 1  further comprising a secondary layer of organic compounds absorber particles. 
     
     
         3 . The fixed bed sorbent as claimed in  claim 2 , wherein the direction of the dialysis liquid flow is from said primary layer to said secondary layer. 
     
     
         4 . The fixed bed sorbent as claimed in  claim 1 , wherein said uremic toxin-treating enzyme particles convert urea to ammonium carbonate. 
     
     
         5 . The fixed bed sorbent as claimed in  claim 4 , wherein said uremic toxin-treating enzyme is urease. 
     
     
         6 . The fixed bed sorbent as claimed in  claim 1 , wherein said cation exchange particles are zirconium phosphate particles. 
     
     
         7 . The fixed bed sorbent as claimed in  claim 1 , wherein said anion exchange particles are zirconium oxide particles. 
     
     
         8 . The fixed bed sorbent as claimed in  claim 2 , wherein said organic compounds absorber particles are activated carbon particles. 
     
     
         9 . The fixed bed sorbent as claimed in  claim 5 , wherein said urease is immobilized on at least one of cellulose, nylon, polycaprolactone and chitosan. 
     
     
         10 . The fixed bed sorbent as claimed in  claim 7 , wherein said zirconium oxide is hydrous zirconium oxide. 
     
     
         11 . The fixed bed sorbent as claimed in  claim 5 , wherein said urease particles have an average particle size in the range of from 10 microns to 1000 microns. 
     
     
         12 . The fixed bed sorbent as claimed in  claim 6 , wherein said zirconium phosphate particles have an average particle size in the range of from 10 microns to 1000 microns. 
     
     
         13 . The fixed bed sorbent as claimed in  claim 7 , wherein said zirconium oxide particles have particle size in the range of from 10 microns to 1000 microns. 
     
     
         14 . The fixed bed sorbent as claimed in  claim 8 , wherein said activated carbon particles have an average particle size in the range of from 10 microns to 1000 microns. 
     
     
         15 . A fixed bed sorbent for removing metabolic waste products from a dialysis liquid, the sorbent comprising a layer of uremic toxin-treating enzyme particles covalently immobilized on a biocompatible material intermixed with cation exchange particles having an average particle size in the range of 50 microns to 200 microns and anion exchange particles;
 wherein said uremic toxin-treating enzyme particles and said cation exchange particles are, when in use, in direct contact with the dialysis liquid; and   wherein the anion exchange particles and cation exchange particles are selected to create pH buffering conditions when in direct contact with the dialysis liquid.   
     
     
         16 . The fixed bed sorbent as claimed in  claim 1 , wherein said cation exchange particles are ammonia absorbers. 
     
     
         17 . The fixed bed sorbent as claimed in  claim 1 , wherein said cation exchange particles comprise ions of a metal whose phosphate is poorly soluble in water.