Matrix for separation of polyethers and method of separation

Abstract

The present invention relates to a separation matrix comprised of a support to the surfaces of which polymer chains have been coupled, wherein each polymer chain presents recurring proton-donating groups and at least the surface of the support is substantially hydrophilic. In the most advantageous embodiment, the support is porous cross-linked agarose, the polymers are poly(acrylic acid) and the proton-donating groups are carboxyl groups. The matrix is useful e.g. to remove PEG from pegylated and/or native compounds in a liquid. Accordingly, the invention also encompasses a method, such as a chromatographic method, wherein the separation matrix according to the invention is used, for example as a pre-treatment of a reaction mixture that comprises unreacted PEG, pegylated proteins and native proteins.

1 . A separation matrix comprising a support having surfaces to which polymer chains have been coupled, wherein each polymer chain presents recurring proton-donating groups and at least the surface of the support is substantially hydrophilic.  
     
     
         2 . The separation matrix of  claim 1 , wherein the support is a crosslinked carbohydrate support.  
     
     
         3 . The separation matrix of  claim 1 , wherein the support is a surface-modified porous synthetic polymer support in which the surfaces exhibit hydroxyl groups.  
     
     
         4 . The separation matrix of  claim 3 , wherein the surface-modified synthetic polymer is crosslinked styrene and/or divinyl benzene.  
     
     
         5 . The separation matrix of  claim 1 , wherein the support is porous.  
     
     
         6 . The separation matrix of  claim 1 , wherein the proton-donating groups are predominantly carboxyl groups.  
     
     
         7 . The separation matrix of  claim 1 , wherein the polymer chains are predominantly poly(acrylic acid) chains.  
     
     
         8 . The separation matrix of  claim 1 , wherein each polymer chain is comprises about 100-500 monomer units.  
     
     
         9 . The separation matrix of  claim 1 , capable of separating polyether target substances from other components in a liquid chromatography method.  
     
     
         10 . The separation matrix of  claim 9 , capable of separating poly(ethylene glycol) (PEG) from pegylated proteins and/or native proteins in a liquid chromatography method.  
     
     
         11 . A system comprising the separation matrix of  claim 1  in a chromatography column.  
     
     
         12 - 14 . (canceled)  
     
     
         15 . A method of separating at least one polyether target substance from other components of a liquid, comprising the steps: 
 (a) providing a separation matrix comprised of a support having surfaces of which polymer chains have been coupled, wherein each polymer chain presents recurring proton-donating groups and at least the surface of the support is substantially hydrophilic;    (b) contacting, at a pH below about 6, the liquid with said separation matrix to allow hydrogen bonding between the proton-donating groups of the separation matrix and proton-accepting ether oxygens of the polyether target substance(s); and    (c) recovering one or more target substances from the separation matrix by contacting said matrix with an eluent.    
     
     
         16 . The method of  claim 15 , wherein the proton-donating groups of the separation matrix are predominantly carboxyl groups.  
     
     
         17 . The method of  claim 15 , wherein the polymer chains of the separation matrix are predominantly poly(acrylic acid) chains.  
     
     
         18 . The method of  claim 15 , wherein in step (b), the pH is below about 4, and preferably below about 3.  
     
     
         19 . The method of  claim 15 , wherein the eluent of step (c) comprises an increasing pH gradient.  
     
     
         20 . The method of  claim 15 , wherein the polyether target substance is PEG or a pegylated compound, such as a protein.  
     
     
         21 . The process of purifying a pegylated compound from a reaction mixture, which comprises a pre-treatment step to remove PEG and a subsequent step to isolate one or more pegylated compounds, wherein the pre-treatment is the method of  claim 15 .  
     
     
         22 . The process of  claim 21 , wherein the compounds are proteins.  
     
     
         23 . The process of  claim 21 , wherein the subsequent step to isolate one or more pegylated compounds is a liquid chromatography step.  
     
     
         24 . A process of converting an ion exchange matrix into the separation matrix of  claim 1 , comprising modifying a support surface of the ion exchange matrix with poly(acrylic acid) groups.  
     
     
         25 . A process of converting an ion exchange matrix into the separation matrix of  claim 1 , comprising grafting vinylethers onto a support surface of the ion exchange matrix.  
     
     
         26 . The process of  claim 25 , wherein vinyl ether monomers are grafted to the support surface of the ion exchange matrix.