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 (“SAP”). 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.
