methods of enabling or improving the ability of a hydrogel to swell in the stomach of an animal and / or increasing the amount of time said hydrogel remains swollen in the stomach are described herein . in one embodiment , a polymer is administered in combination with one or more ph modifying agents which raise and maintain the ph of the micro environment of the polymer and / or the stomach in order inducing swelling in the polymer . the polymer can be a homopolymer , a copolymer , or a polymer blend or composite . in one embodiment , the polymer is a superabsorbent polymer . the polymers can also be administered with one or more active agents , such as appetite suppressants . the ph modifying agent and / or the active agent can be administered simultaneously with the polymer in the same dosage form , simultaneously with the polymer in separate dosage forms , or sequentially . the compositions are formulated for oral administration . the formulation can include drugs for delivery to the stomach , such as antibiotics , or the hydrogel can be used as a filler , for example , for obesity control . the formulation an also be used to enhance gastric retention , for example , for controlled drug delivery . methods of delivering a drug are also described herein , along with medicaments for carrying out the methods of the present invention .