The present invention features modified superporous hydrogels (SPHs) and methods for their formation. The SPHs of the present invention are prepared by careful selection of the hydrophobic/hydrophilic reactive ingredients and by harmonizing the foaming and polymerization reactions, which results in the formation of SPHs having a homogeneous structure and favorable physical and mechanical properties, including swelling, strength, ruggedness, and resiliency. The SPHs of the present invention are particularly useful when employed in very harsh swelling environments, such as the low pH environment of the gastric fluid of the stomach, for extended periods of time.