Gamascintigraphic in Vivo-in Vitro Evaluation of Floating Matrix Tablet

Background of the work: Gastroretentive drug delivery system can retain the dosage form in the gastric region for several hours. Prolong gastric retention helps in improving bioavailability and improves solubility of drugs that are less soluble in a high pH environment. For designing of GRDDS Atenolol was selected as a model drug. It has been used for the treatment of hypertension. Atenolol has short elimination half-life, stable at pH 1.2 and as the pH increase, the drugs becomes unstable and thus low oral bioavailability.In order to improve its therapeutic effectiveness Atenolol is designed in the form of floating tablet formulation. Purpose: The aim of the present work was to develop hydrodynamically balanced system for atenolol, β-blocker as a single unit floating tablet. Formulation includes the use of rate controlling polymer such as Locust Bean gum (LBG) in combination of HPMC K4M and gas generating agent Sodium bicarbonate. Summary and conclusion: Tablet was prepared by direct compression method and evaluated for physico-mechanical properties. The statistical method was utilized to optimize the effect of independent variables namely amount of HPMC K4M, LBG and three dependent responses such as Cumulative drug release, Floating lag time, Floating time. Graphical and mathematical analysis of the results allowed the identification and quantification of the formulation variables influencing the selected responses. To study the gastrointestinal transit of the optimized Gastroretentive formulation, the in vivo Gamascintigraphy was carried out in six healthy rabbits, after radio labeling the formulation with 99mTc. The transit profiles demonstrated that the dosage form was retained in the stomach for more than 5 hrs. The study signifies the potential of the developed system for stomach targeted delivery of Atenolol with improved bioavailability.