Filtration

Abstract

Filtration methods comprise virus-filtering a solution containing a least one macromolecule. The total salt content of the solution for virus-filtering is within the range of from about 0.2 M up to saturation with the salt. Salts that can be used in the filtering methods include sodium chloride, potassium chloride, sodium acetate, sodium citrate, sodium phosphate, potassium dyhydrophosphate and combinations thereof.

1 . A filtration method comprising virus-filtering a solution containing at least one macromolecule, wherein the total salt content of the solution is within the range of about 0.6 M up to saturation of the solution with the salt concerned.  
     
     
         2 . A method according to  claim 1 , characterized in that the total salt content of the solution lies within the range of from 0.4 up to 2.5 M.  
     
     
         3 . A method according to  claim 2 , characterized in that the total salt content of the solution lies within the range of from 0.6 up to 2.0 M.  
     
     
         4 . A method according to  claim 1 , characterized in that the salt is selected from the group consisting of sodium chloride, potassium chloride, sodium acetate and sodium citrate and combinations thereof.  
     
     
         5 . A method according to  claim 1 , characterized in that the macromolecule is selected from the group consisting of proteins, polysaccharides and polypeptides and combinations thereof.  
     
     
         6 . A method according to  claim 5 , characterized in that the macromolecule is factor IX.  
     
     
         7 . A method according to  claim 5 , characterized in that the macromolecule is gammaglobulin.  
     
     
         8 . A method according to  claim 5 , characterized in that the macromolecule is albumin.  
     
     
         9 . A method according to  claim 5 , characterized in that the macromolecule is antithrombin III.  
     
     
         10 . A method according to  claim 5 , characterized in that the macromolecule is a deletion derivative of recombinant factor VIII.  
     
     
         11 . A method according to  claim 1 , characterized in that the virus-filtering process is carried out in accordance with the “dead-end” filtering technique.  
     
     
         12 . A method according to  claim 1 , characterized in that the virus-filtering process reduces the content of non-enveloped viruses by at least 4 logs.  
     
     
         13 . A method according to  claim 1 , wherein a non-lipid enveloped virus is removed from the solution.  
     
     
         14 . A method according to  claim 13 , wherein the non-lipid enveloped virus is selected from the group consisting of hepatitis virus A, polio virus and parvo virus.  
     
     
         15 . A method according to  claim 1 , wherein a lipid-enveloped virus is removed from the solution.  
     
     
         16 . A method according to  claim 15 , wherein the lipid-enveloped virus is selected from the group consisting of hepatitis virus B, hepatitis virus C and the human immuno-deficiency virus (HIV).  
     
     
         17 . A method according to  claim 1 , wherein a virus smaller than about 350 nm is removed from the solution.  
     
     
         18 . A method according to  claim 17 , wherein the virus removed from the solution is smaller than 200 nm.  
     
     
         19 . A method according to  claim 18 , wherein the virus removed from the solution is smaller than 150 nm and larger than about 20 nm.