This study aimed to develop a new in situ floating gel system that prevents oedema, congestive heart failures, and hypertension using hydrochlorothiazide. Sodium alginate solutions with a concentration of 0.25, 0.5, 1.0, and 1.5% (w/v) were formed by stirring alginate into ultra-pure water, with 0.25 percent (w/v) sodium citrate and 0.075 percent (w/v) calcium chlorine and heating up to 60 /v, then dissolved into 10 mL (pH 1.2) solution of 0.1N hydrochloride. Using 0.1N sodium hydroxide, the solvent was neutralized. A 1% (w/v) control solution was formed by dissolving hydrochlorothiazide into a 0.6% (w/v) solution of aqueous sodium alginate. Ultra-pure water provided a 1% (w/v) solution of hydrochlorothiazide. The resulting in situ alginate gel hydrochlorothiazide solution for viscosity and gelling proprieties was tested. The resulting gel was tested for in-vivo gelation and estimation of viscosity, physical appearance and drug content, in-vitro drug release, and gel water absorption measurement and was found to be compatible with the results discussed. This study shows that oral administration of aqueous solutions containing sodium alginate contributes to in situ stomach gel growth. The complete 32 factorial design findings indicate that sodium alginate concentration and calcium chloride concentration greatly influenced dependent variables such as viscosity, the content of medicinal products, Q50 and Q80.