Objective: The present investigation deals with the formulation, optimization and evaluation of sodium alginate based floating oral In situ gel of Ranitedine HCl. Sodium alginate used as a polymer and CaCO3 was used as a cross-linking agent. In-situ forming polymeric formulation drug delivery systems is in sol form before administration in the body, but once administered, undergoes gelation in-situ to form a gel. The formulation of gel depends upon factors like temperature modulation, pH changes, presence of ions and ultraviolet irradiation from which drug gets released in sustained and controlled manner. Methods: The objective of this study was to develop a novel in- situ gel system for sustained drug delivery using natural biodegradable p...