floating drug delivery system

The aim of the present work was to develop and optimize gastroretentive floating system of Gemifloxacin mesylate using HPMC polymers, Gelucire 50/13 and Polyox WSR 301 to improve oral bioavailability of Gemifloxacin mesylate floating tablets by increasing gastric residence time. The tablets were prepared by direct compression method. The effect of polymers concentration and viscosity grades of HPMC on drug release profile was evaluated. The result of in vitro dissolution study showed that the drug release profile could be sustained by increasing the concentration of HPMC and Polyox WSR 301. The optimized formulation (F12) containing HPMC K100M, Gelucire 50/13 and Polyox WSR301 showed 99.12% drug release at the end of 12h. The optimized formulations (F12) containing showed desired buoyancy (floating lag time of about 35 seconds and total floating time of >12h). Optimized formulation (F12) followed diffusion controlled zero order kinetics and non-fickian transport of the drug. FTIR studies revealed the absence of any chemical interaction between drug and polymers used.

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.

  Technological attempts have been made in the research and development of rate-controlled oral drug delivery systems to overcome physiological adversities, such as short gastric residence times (GRT) and unpredictable gastric emptying times (GET). It is known that differences in gastric physiology, such as, gastric pH, and motility exhibit both intra-as well as inter-subject variability demonstrating significant impact on gastric retention time and drug delivery behavior. This triggered the attention towards formulation of stomach specific (gastro retentive) dosage forms. This dosage forms will be very much useful to deliver ‘narrow absorption window’ drugs. Several approaches are currently utilized in the prolongation of the GRT, including floating drug delivery systems (FDDS), swelling and expanding systems, polymeric bioadhesive systems, high-density systems, modified-shape systems and other delayed gastric emptying devices. In this review, current & recent developments of Stomach Specific FDDS are discussed. Key words: floating drug delivery system, hydrodynamically balanced system, effervescent, non-effervescent, gastric residence time.