Media For Membrane Ion Exchange Chromatography Based On Polymeric Primary Amines, Sorption Device Containing That Media, And Chromatography Scheme And Purification Method Using The Same

Abstract

Media and devices, such as anion exchangers including such media, wherein the media is a membrane having a surface coated with a polymer such as a polyallylamine. The resulting membrane offers stronger binding of protein impurities and superior removal of host cell proteins from biological samples than conventional ligands based on quaternary ammonium salts, including trimethylammonium ligands. Also described is a chromatography scheme and method for purifying monoclonal antibodies, wherein the anion exchange sorber is placed downstream of an affinity column (such as Protein A or Protein G affinity column) and optionally one or more polishing devices such as cationic exchange columns. Little or no dilution of the cation exchanger pool (or affinity column exchange pool where no cation exchanger is used) is necessary to lower the conductivity of the sample. The sorber functions well to strongly bind host cell proteins and other impurities in biological samples even at high conductivities and pH.

1 . A method of purifying a biological sample comprising antibodies and impurities, said sample having an ion conductivity up to 22 mS/cm, comprising subjecting said sample to porous sorptive media comprising a porous substrate and a porous coating on a surface of said substrate, said coating comprising one or more polymeric primary amines or copolymers thereof. 
   
   
       2 . The method of  claim 1 , wherein said ion conductivity is from 9.7 mS/cm to 22 mS/cm. 
   
   
       3 . The method of  claim 1 , wherein the ion conductivity of said biological sample is about 15 mS/cm. 
   
   
       4 . The method of  claim 1 , wherein said substrate comprises cellulose. 
   
   
       5 . The method of  claim 2 , wherein said substrate comprises cellulose. 
   
   
       6 . A method of purifying a biological sample comprising antibodies and impurities, said sample having a salt concentration up to 200 mM NaCl, comprising subjecting said sample to porous sorptive media comprising a porous substrate and a porous coating on a surface of said substrate, said coating comprising one or more polymeric primary amines or copolymers thereof. 
   
   
       7 . The method of  claim 6 , wherein said salt concentration is from 100 to 150 mM NaCl. 
   
   
       8 . The method of clam  6 , wherein said substrate comprises cellulose. 
   
   
       9 . The method of  claim 7 , wherein said substrate comprises cellulose.