The present disclosure relates generally to compositions comprising a crosslinked cation-binding polymer comprising monomers containing carboxylic acid groups, and a base, wherein the polymer contains less than about 20,000 ppm of non-hydrogen cations, and wherein the base is present in an amount sufficient to provide from about 0.2 equivalents to about 0.95 equivalents of base per equivalent of carboxylic acid groups in the polymer. The present disclosure also relates to methods of preparation of said compositions and methods of using said compositions to treat various diseases or disorders, including those involving ion and/or fluid imbalances.
