Formulation and Evaluation of Bilayer Floating Tablets of Metformin Hydrochloride and Glibenclamide

The present research work was an attempt to design a formulation of Bilayer floating tablets with Metformin HCl as sustained release layer and Glibenclamide as immediate release layer for the treatment of type II diabetes mellitus. The extended release was prepared by wet granulation method using HPMC K 100M as sustained release polymer and sodium bicarbonate as gas generating agent to reduce floating lag time. Immediate release layer were prepared by direct compression using sodium starch glycolate as super disintegrant. Gastro retentive floating drug delivery systems have been designed to increase its residence time in the stomach. The granules were evaluated for bulk density, tapped density, Compressibility index, and hausner's ratio. The granules showed satisfactory flow properties. The tablets were subjected to weight variation test, hardness test, friability test, drug content test and swelling index. All the tablets were passed the tests. With the incorporation of a gas generating agent the floating lag time was 27 sec, and the duration of floating was >8hrs. The drug release from the prepared tablets was sufficiently sustained (more than 8hrs). The release kinetics of the Bilayer floating tablet was evaluated using regression coefficient analysis. The formulated tablets shows a Zero order drug release and the mechanism is correlated well with Korsmeyer peppas mode with super case II transport mechanism. Stability studies did not show any changes in physical appearance, physicochemical properties, and drug release.