The present study was carried out with an objective of preparation and in vitro evaluation of floating tablets of hydroxypropyl methyl cellulose (HPMC) and polyethylene oxide (PEO) using ranitidine hydrochloride as a model drug. The floating tablets were based on effervescent approach using sodium bicarbonate a gas generating agent. The tablets were prepared by dry granulation method. The effect of polymers concentration and viscosity grades of HPMC on drug release profile was evaluated. The effect of sodium bicarbonate and stearic acid on drug release profile and floating properties were also investigated. The result of in vitro dissolution study showed that the drug release profile could be sustained by increasing the concentration of HPMC K15MCR and Polyox WSR303. The formulation containing HPMC K15MCR and Polyox WSR303 at the concentration of 13.88% showed 91.2% drug release at the end of 24 hours. Changing the viscosity grade of HPMC from K15MCR to K100MCR had no significant effect on drug release profile. Sodium bicarbonate and stearic acid in combination showed no significant effect on drug release profile. The formulations containing sodium bicarbonate 20 mg per tablet showed desired buoyancy (floating lag time of about 2 minutes and total floating time of >24 hours). The present study shows that polymers like HPMC K15MCR and Polyox WSR303 in combination with sodium bicarbonate as a gas generating agent can be used to develop sustained release floating tablets of ranitidine hydrochloride.
Key words: Floating drug delivery system, gastroretentive drug delivery system, HPMC, PEO, ranitidine hydrochloride, sustained release