Formulation and Evaluation of Bilayer Floating Tablets for Diabetes Mellitus

Abstract

Site specific or targeting drug to the stomach is found to be a novel approach during last decade. One of the approaches to develop gastro retentive drug delivery system which is designed to aim increased gastric residence time of the dosage form. Among various ways to increase gastric residence time; floating bioadhesive is one of them. Formulation of immediate release layer with floating bioadhesive sustained release layer to develop as a bilayer tablet is the novel purpose of this investigation. For immediate release layer and floating bioadhesive sustained release layer Repaglinide and Glipizide used as a model drug respectively during the study. With the aim bilayer floating bioadhesive tablet is prepared for giving immediate release of Repaglinide to attain onset of action quickly i.e. attaining therapeutic level with few minute and subsequently gastric retention time was prolonged with a controlled release of Glipizide from floating bioadhesive sustained release layer i.e. maintaining therapeutic level of drug for desired time period which is up to 12 hrs. Immediate release tablets of Repaglinide were initially prepared by using sodium starch glycolate as a superdisintegrant, microcrystallines cellulose as a diluents and sodium lauryl sulphate as a solubilizing agent. Superdisintegrant promotes the disintegration and ultimately dissolution of drug; consequently release rate of drug increases and its absorption lead to faster onset of action. Optimized immediate release layer selected from batches F1, F2 and F3 on the basis of drug release, wetting time and disintegration time. F1 was selected as optimized immediate layer for the formulation bilayer tablet. Further the formulated tablet A6 and C2 was found to be well floated in rabbit stomach for more than 8 hrs as well it was found that C2 does not alter its position in early hrs when subjected for In-vivo study, so it can be concluded that the formulated tablet was satisfactory adhered to the rabbit stomach mucosa. newline newline