Bilayer Floating Tablet Technology: An Overview

Novel drug delivery system overcomes the physiological problems of gastric retention by decreasing fluctuations in blood drug concentration with consequent reduction in undesirable toxicity and poor efficiency. Incorporation of drug in controlled release gastroretentive dosage forms which can remain in the gastric region for several hours would significantly prolong the gastric residence time of drugs and improve bioavailability, reduce drug waste and enhance the solubility of drugs that are less soluble in high pH environment. Several approaches are currently utilized in the prolongation of GRT, including floating drug delivery system, swelling and expanding systems, polymeric bioadhesive systems, high density systems, modified shape systems and other delayed gastric emptying devices. Bilayer floating drug delivery systems exhibit a unique combination of floatation and bilayer which prolongs residence in the stomach. Floatation due to bulk density less than gastric fluids and so, remain buoyant in the stomach for a prolonged period of time, releasing the drug slowly at the desired rate from the system and increase the bioavailability of narrow absorption window drugs. Bilayer tablet is better than the traditionally used dosage forms suitable for sequential release of two drugs in combination it is also capable of separating two incompatible substances and also for sustained release. Rahul kumar Garg, Indrajeet Singhvi Pacific College of Pharmacy, Pacific University, Udaipur, India. Submission: 3 June 2015 Accepted: 11 June 2015 Published: 25 June 2015 www.ijppr.humanjournals.com Citation: Rahul kumar Garg et al. Ijppr.Human, 2015; Vol. 3 (3): 302-322. 303 INTRODUCTION The oral route is considered as the most promising route of drug delivery. Conventional drug delivery system achieves as well as maintains the drug concentration within the therapeutically effective range needed for treatment, only when taken several times a day 1 . This results in a significant fluctuation in drug levels. Recently, several technical advancements have led to the development of several novel drug delivery systems (NDDS) that could revolutionize method of medication and provide a number of therapeutic benefits 2 . The most important objectives of these new drug delivery systems are: First, it would be single dose, which releases the active ingredient over an extended period of time. Second, it should deliver the active entity directly to the site of action, thus, minimizing or eliminating side effects. To overcome the limitations of conventional drug delivery system, bilayer floating tablets have been developed. Drugs that have narrow absorption window in the gastrointestinal tract (GIT) will have poor absorption. For these drugs, gastroretentive drug delivery systems offer the advantages in prolonging the gastric emptying time. The relatively brief gastric emptying time (GET) in humans which normally averages 2-3 h through the major absorption zone, i.e., stomach and upper part of the intestine can result in incomplete drug release from the drug delivery system leading to reduced efficacy of the administered dose 3 . Therefore, control of placement of a drug delivery system (DDS) in a specific region of the GI tract offers advantages for a variety of important drugs characterized by a narrow absorption window in the GIT or drugs with a stability problem 4 . These considerations have led to the development of a unique oral controlled release dosage form with gastroretentive properties. After oral administration, such a drug formulation would be retained in the stomach and release the drug there in a controlled and prolonged manner, so that the drug could be supplied continuously to its absorption sites in the upper gastrointestinal tract 5 .