BILAYER FLOATING TABLET- AN EMERGING TREND: A REVIEW

The absorption of drugs through the gastrointestinal tract is a highly variable process; prolonging gastric retention of the dosage form extends the time for drug absorption. A novel drug delivery system overcomes the physiological problems of short gastric retention by decreasing fluctuations in blood drug concentration with subsequent reduction in undesirable toxicity and poor efficiency. Various approaches have been introduced to prolong gastric residence time, including floating drug delivery systems (FDDS), swelling and expanding systems, polymeric bio-adhesive systems, high density systems, modified shape systems, etc. Bilayer floating drug delivery systems are the most promising drug delivery system, which exhibits a unique combination of floatation and bilayer, leading to prolongation in residence time in the stomach. Floatation is achieved due to bulk density being less than gastric fluids. So, the system remains buoyant in the stomach for a prolonged period, releasing the drug slowly at the desired rate and thus increasing the bioavailability of narrow absorption window drugs. This review entitles the floating drug delivery system principle and current technology used in the development. Also, it sheds light on the advantages and Total 6 disadvantages to be there disadvantages, the need for floating bilayer tablets, challenges in bi-layer tablet manufacturing, and characterization and evaluation methods for bilayer floating tablets.