DEVELOPMENT, FORMULATION AND EVALUATION OF A BILAYER GASTRIC RETENTIVE FLOATING TABLETS OF RANITIDINE HCL AND CLARITHROMYCIN USING NATURAL POLYMERS

Objective: Bilayer gastric retentive floating tablets (BGRFT) with ranitidine HCl and clarithromycin using natural gums have been developed to prolong the gastric residence time and increase drug bioavailability. Literature review revealed no published studies on the present study.Methods: Immediate release (IR) layer prepared by using different diluents and super disintegrants like sodium starch glycolate, crosscarmellose sodium and crospovidone. Controlled released (CR) layer prepared by using neem gum, damar gum and copal gum. Prepared tablets were evaluated for in vivo and in vitro buoyancy, in vitro dissolution studies and fourier transformation-infrared spectroscopy (FTIR). Drug release was evaluated with zero and first order for release kinetics, Higuchi, Hixson-Crowell erosion models for release mechanism.Results: Prepared IR layer followed first order rate kinetics and CR layer followed zero order rate kinetics with non-Fickian diffusion mechanism. BGRFT also showed similar results as that of the individual layer. Optimized formulations were characterized by FTIR studies and found no interactions between drug and polymer.Conclusion: The results demonstrate the feasibility of the model in the development of BGRFT. BGRFT enhanced the drug release and finally the bioavailability of clarithromycin when compared with commercial tablet (Biomycin 250). The present study could establish the suitability of neem gum as CR polymer in the design of BGRFT

QUALITY BY DESIGN APPROACH FOR DEVELOPMENT AND OPTIMIZATION OF CHITOSAN BASED FLOATING MICROSPHERES FOR TOPOTECAN HCl

Objective: To develop floating microspheres for the topotecan in order to prevent its onversion into inactive carboxylate form in intestinal pH conditions so as to improve its bioavailability. Methods: Chitosan based porous floating microspheres containing sodium bicarbonate by coacervation technique were developed. Quality by design approach using Box-Behnken Design was adopted to assess the influences of selected formulation variables and their importance on the quality of the finished product. Results: The selected model was analyzed and optimized. The microspheres floated immediately without any lag time upon addition into water and remained floatable for more than 24 hours. The optimized formulation was found to have the particle size of 379.2 µm, entrapment efficiency of 76.3% and the drug release rate constant of 0.29 h-1 i.e., the release was extended up to 16 hours. Conclusion: The results affirmed that controlled release porous microspheres of Topotecan with inherent floating without lag were successfully developed