This study aimed to formulate, develop, and evaluate sustained-release gastroretentive drug delivery systems for Quetiapine Fumarate (QF). The preformulation study involved determining the drug's organoleptic properties, melting point (173.33±0.58°C to 176.00±1.00°C), and UV absorbance maxima (248nm). Method validation confirmed the UV spectroscopic method's accuracy, precision, ruggedness, and robustness, with recovery percentages ranging from 99.152% to 100.031% and %RSD under 1%. Solubility studies revealed QF's solubility in water, methanol, ethanol, 0.1N HCl, and phosphate buffer pH 6.8.