The present disclosure relates generally to crosslinked cation-binding polymers comprising monomers containing carboxylic acid groups, wherein the polymer contains calcium and/or magnesium cations that are counterions to about 15% to about 35% of the carboxylic acid groups in the polymer. The present disclosure also relates to methods of preparation of the polymers, and compositions, formulations, and dosage forms containing the polymers, and methods of using the polymers, compositions, formulations, and/or dosage forms to treat various diseases or disorders, including those involving ion and/or fluid imbalances.
