FORMULATION AND EVALUATION OF BILAYER FLOATING TABLETS OF METOPROLOL SUCCINATE
Metoprolol succinate is a beta blocker. Mainly used for the treatment of hypertension and angina pectoris. Metoprolol succinate is a suitable candidate for Controlled Release administration due to its short elimination time 3-7 hrs. The aim of present investigation is to increase the gastric residence time by preparing gastro retentive floating bilayered tablet thereby improving bioavailability. The prepared floating bilayer tablets were evaluated for hardness, weight variation, thickness, friability, drug content uniformity, buoyancy lag time, total floating time, water uptake (swelling index) and in-vitro dissolution studies. Bilayer floating tablets was formulated using direct compression technique. The immediate release layer comprised of cross caramellose sodium as a super disintegrant and the sustained release layer comprised of Ethyl celluloseE15, HPMC K4M, Guar gum and Xanthan gum as release retarding polymers. Sodium bicarbonate was used as a gas generating agent in the floating layer. The immediate release layer containing 5% cross caramellose sodium was found to be optimum and the floating sustained release tablet of metoprolol succinate (F10) containing Guar gum and HPMC K4M showed sustained release up to 12h. The final optimized formulation released 98.73% of metoprolol succinate in 12h while the floating lag time was 98 sec and the tablet remained floatable throughout the studies. Accelerarated Stability studies revealed that F10 were stable when stored at room temperature as well as different accelerated temperature and humidity conditions for a period of three months. The values were within permissible limits