FORMULATION AND EVALUATION OF BILAYER FLOATING TABLETS OF RANITIDINE HCL USING NATURAL POLYMERS

A. Praveen, T. Monika and K. Sandeep*

ABSTRACT

The purpose of this study is to prepare a bilayer gastro retentive tablet of ranitidine using direct compression technology and optimize the type and concentration of polymer to give maximum retentive effect with good drug release profile. Ranitidine H2 receptor antagonist having short biological half life (2-3.5 h), absorption in the initial part of the small intestine and 50% absolute bioavailability of drug favor development of sustained release floating formulation. In this study, a bilayer tablet was prepared which contains an immediate release portion and a floating layer. XANTHUM GUM, HPMC-K-4M, HPMC-E-15, GUAR GUM were used as gel forming agents either alone or in combination. Sodium bicarbonate, and citric acid as gas generating agent, lactose as additive combine with the polymer to form the floating layer.[1] The bilayer tablets were characterized by lag time, floating time, weight variation, drug content and dissolution profile. Best Formulation BLF6 [Xanthum gum (1:1)] shows lag time of 25 s, floating time of 24 h and drug release of 99.85%. The best formulation was taken up for animal studies as approved by Institutional Animal Ethical Committee. The X-ray studies for floating properties of tablet and the in vivo bioavailability studies for the formulation was carried out using rabbits which showed a significant increase in bioavailability of drug as compared with conventional dosage forms. The optimized formulation was subjected to stability studies at 40 ± 20 and 75 ± 5% RH for period of three months. Short term stability studies were carried for optimized formulation showed good result.

Keywords: Bilayer tablet, Floating tablet, Gastro retentive tablet, Ranitidine tablet.