Extended release model allows at least a twofold decrease in the drug dose frequency compared to the conventional (immediate release) dosage form. The current study investigates the guar gum modified release tablet containing gylcine and guar gum with different ratios and investigate the modified release tablets containingpolyvinyl-pyrolidone (PVP) by wet granulation method . The tablets were tested according to the British Pharmacopeia (BP) with the appropriate tests. The relation of the swelling factor to the concentration of guar gum and glycine depended on the ratios used such that decrease in glycine or increase in guar gum increased the swelling factor. The formulations having low amounts of glycine and high amounts of guar gum mainly depend on the high swelling index of guar gum. High glycine and low guar gum ratios enhance the matrix erosion in direct proportion manner. This proved that the higher swelling and the lower erosion could be obtained by reducing the glycine and increasing the guar gum to form stronger gel for the design extended release formulations. Moreover, the hydrophilic property of the PVP enhances dramatically the swelling index of the matrix with unclear increase in the erosion. The PVP increases the swelling of the matrix of formulation 2 from 297.6% to 342.7% and the erosion from 39.1% to 40.6%. The (5 % glycine and 55 % guar gum) formulation was the best formulation out of the glycine and guar gum blends for the sustained release purposes as it described the slowest release out of the guar gum and glycine formulations which enabled the table to be administered every 16 hours. Additionally, on adding polyvinyl-pyrolidone (PVP), it enabled the release of the theophylline dose over 20hours, which could lead to one-day administration of the theophylline tablet. According to the aforementioned results, the formulation including the glycine, guar gum and PVP blends was found to be the best model for the extended release tablets.