Patent ID: 8222039

Claim:
A process for the separation of a water-soluble poly(ethylene oxide) (PEO) polymer of interest from other water-soluble poly(ethylene oxide) polymers, initially present as one component of a mixture, wherein the polymer of interest contains a different number of reactive terminal groups than the other water-soluble polymers in the mixture, wherein said reactive terminal groups are hydroxyl, sulfhydryl, mercapto, halide, carboxylate, amino, aldehyde, maleimide, or —CH 2 —X wherein X is a halide or sulfonic acid ester, said process comprising: reacting the initial mixture of polymers to covalently bind the reactive terminal group with a derivatizing molecule, said derivatizing molecule being capable of forming a covalent bond with said reactive terminal group, wherein said derivatizing molecule has 2 or 3 ionizable groups after the covalent binding, and wherein said 2 or 3 ionizable groups are all independently selected from the group consisting of carboxylate, phosphate, phosphonate, borate, sulfonate, and sulfate groups, or wherein said 2 or 3 ionizable groups are all independently selected from the group consisting of amine, aromatic amine, and heterocyclic nitrogen containing groups; and subjecting the reacted polymer mixture to ion exchange to separate the derivatized (PEO) polymer of interest from the other derivatized PEG polymers.