Studies on Formulation Development and Evaluations on Losartan Floating and Bioadhesive Drug Delivery System

The present investigation was undertaken to formulate and evaluate the losartan floating and bioadhesive drug delivery system using different polymers in different ratios. The main objective of the present work is to develop a novel osmotically controlled drug delivery system of losartan. It was aimed to prepare for prolonged residence in the stomach over conventional gastro retentive approaches. As the drug has short biological half-life (2 hours) hence it becomes necessary that it should be administered in 2 or 3 doses of 2.5 to 10 mg per day. Thus, the development of controlled-release dosage forms would clearly be advantageous. Formulated tablets gave satisfactory results for various evaluation parameters like tablet hardness, friability, weight variation, thickness, floating lag time, floating duration, content uniformity, ex vivo osmotically controlled strength and in vitro drug release. In all formulations Carbopol 974P is used to add osmotically controlled strength but the concentration of this polymer has significantly influenced the drug release due to its retarding property. Comparing the three different grades of Hydroxy propyl methyl cellulose (HPLC) (K4M, K15M and K100M), it was found that low-viscosity grades of HPMC K4M formulations released drug rapidly compared to K15M HPLC and K100M HPLC. Among all formulations K15M grade provided better controlled release characteristics with excellent drug release and in vitro buoyancy. From the above, it was also evident that at higher viscosity grades of polymer concentrations, the rate of drug release was retarded greatly.