DEVELOPMENT AND IN VITRO EVALUATION OF FLOATING DRUG DELIVERY SYSTEM OF VERAPAMIL HCl

Gastro retentive controlled release drug delivery system of Verapamil HCl was formulated to increase the gastric retention time of the dosage form with controlling the drug release pattern. Different grades of hydroxy propyl methyl cellulose derivatives; Methocel K4M and Methocel K15MCR were incorporated for their gel forming properties. Tablet buoyancy was achieved by incorporating a mixture of gas generating agents; sodium bicarbonate and anhydrous citric acid. In vitro dissolution studies were carried out for eight hours using USP XXII paddle type apparatus using 0.1N HCl as the dissolution medium. All the gastro retentive tablets showed good in vitro buoyancy. Tablets swelled radially and axially during buoyancy study. The release kinetics were explored and explained with zero order, first order, Higuchi and Korsmeyer equations. The release rate, extent and mechanisms were found to be governed by polymer type and content. Formulations were characterized by physical characterization, drug loading content and Fourier Transform Infrared spectroscopy (FT-IR). Good results were obtained in the tests and the FT-IR spectroscopic studies indicating no interaction and the stability of Verapamil HCl in the used excipients. Based up on the results, it was proved that a proper balance between rate retarding polymer and gas forming agents is obligatory for efficient buoyancy and controlled drug release.