ABSTRACT:
The objective of this research work was to formulate and evaluate the floating drug delivery system containing theophylline as a model drug. Theophylline tablets were prepared by granulation method incorporating Methocel as swelling polymer, sodium bicarbonate, as gas generating agent, citric acid as release rate enhancer and excipients such as Magnesium stearate and lactose. Dissolution profiles were studied in medium 0.1N Hcl. The influence of variables like polymer type, citric acid on theophylline release profile was studied. The release mechanisms of theophylline from floating tablets were evaluated on the basis of Peppas’s model. The ‘n’ value of all the formulations ranges from lowest 0.752 to highest 0.960 which was in the range of 0.45-n-1.0 which indicate the mechanism of release of theophylline was anomalous (non-Fickian) transport. The thickness, hardness, friability, weight variation, drug content uniformity of the formulated floating tablets was evaluated. Tablets were also evaluated for swelling index, floating lag time and floating duration of all the formulations were within the range and floating duration of all the formulations were in the range of 7 to >10 hrs. Based on the evaluation results, S3 formulation was selected as the best formulation and was checked for stability at different temperatures 25ºC / 60% RH, 35ºC / 65% RH and 40ºC / 75% RH. These results indicated that the selected formulation was stable. The drug release profile of the best formulation was well controlled and uniform throughout the gastrointestinal tract. Scanning electron microscopy (SEM) study represents the formation of gel structure. Different excipients were tested for their compatibility with theophylline such as FT-IR and DSC studies, which revealed that there is no chemical interaction occurred with other excipients.