In the present work, a gastroretentive in situ gelling liquid formulation for controlled delivery of ranitidine was formulated using sodium alginate (low, medium and high viscosity grades), calcium carbonate (source of cations) and ranitidine. Prepared formulations were evaluated for viscosity, buoyancy lag time and buoyancy duration, drug content and in vitro drug release. Formulation variables such as concentration of sodium alginate, calcium carbonate and drug significantly affected the formulation viscosity, floating behavior and in vitro drug release. Analysis of the release pattern showed that the drug release from in situ gel followed a diffusion mechanism.
