Preparation and In-Vitro Evaluation of Repaglinide Floating Oral Delivery System

Floating tablets of repaglinide were developed to prolong residence time and there by increased drug bioavalibility. Repaglinide was chosen as a model drug because it has a very short half life (1hr), low bioavailability (50%) and poor absorption in the upper intestinal tract. The tablets were prepared by effervescent technique using two different swelling polymers Hydroxy propyl methyl cellulose (HPMC) K15M and Sodium carboxy methyl cellulose (Na CMC) either alone or in combination with other standard excipients. Tablets were evaluated for physical properties viz, thickness, hardness, friability, weight variation, drug content uniformity, floating lag time, floating duration and swelling index. Further tablets were evaluated for in vitro release characteristics for 12 hrs. The prepared tablets exhibited good in vitro buoyancy and dissolution studies. The tablets swelled readily and axially during in vitro buoyancy studies. The release mechanism of repaglinide from floating tablets was evaluated on the basis of Peppas model. The ‘n’ (indicative of mechanism of drug release) value of all the formulations ranges from lowest 0.7327to highest 0.9772 which was in the range of 0.45<n<1.0 which indicate the mechanism of release of repaglinide was anomalous (Non-Fickian) transport. Floating tablets prepared based on combination of two polymers namely HPMC K15M and Na CMC exhibited desired floating and prolonged release for 12 hrs when compared with floating tablets prepared with individual polymer.