Development and Evaluation of Oral Gastroretentive Floating Matrix Tablet of Famotidine

Conventional drug therapy requires periodic doses of therapeutic agents. These agents are formulated to produce maximum stability, activity and bioavailability.  Floating drug delivery systems (FDDS) have a bulk density less than gastric fluids and so remain buoyant in the stomach without affecting gastric emptying rate for a prolonged period of time. While the system is floating on the gastric contents drug is released slowly at the desired rate from the system. The present study mainly focuses on the development and evaluation effervescent based floating matrix tablet of famotidine. This oral drug delivery offers several advantages over the standard conventional oral dosage forms. Effervescent based floating matrix tablet of famotidine was prepared using sodium bicarbonate as effervescent agent and by incorporating hydrophobic agent stearic acid which retards the drug release and allow the dosage form to float on gastric fluid for several hrs. Then the tablet was evaluated for hardness, friability, drug content and in vitro drug release. On the basis of the preliminary trials, a 32 full factorial design was employed to study the effect of independent variables, HPMC K4M: Carbopol 934P ratio (X1) and concentration of effervescent agent (X2) on dependent variables like floating lag time, Q4 and Q8. The best batch (F3) exhibited optimum floating lag time (16 sec), drug content (98.94%), Q4 (54.36 %), Q8 (93.98%) and similarity factor (83.92). The controlled release of famotidine was observed and good fit to the zero order was demonstrated.