Design, development, and in vitro evaluation of sustained release tablet formulations of olmesartan medoxomil

Objective: The purpose of present research work is to develop the sustained release formulation for Olmesartan medoxomil using 3 2 factorial design.Olmesartan an Antihypertensive agent, angiotensin-II receptor (type AT1) blocker and BCS class-II agent.Methods: Sustained Release tablets of Olmesartan medoxomil were prepared using different quantities of HPMCK4M and Xanthan Gum in combinations by direct compression technique.The concentration of Polymers, HPMCK4M and Xanthan gum required to achieve the drug release was selected as independent variables, X 1 and X 2 respectively whereas, time required for 10% of drug release (t 10% ), 50% (t 50% ), 75% (t 75% ) and 90% (t 90% ) were selected as dependent variables.Results: Nine formulations were prepared and are evaluated for various pharmacopoeial tests.The results reveals that all formulations were found to be with in the pharmacopoeial limits and In vitro drug release profiles of all formulations were fitted in to various Kinetic models.The statistical parameters like intercept, slope & correlation coefficient were calculated.Polynomial equations were developed for dependent variables.Validity of developed polynomial equations were checked by designing 2 check point formulations (C 1 , C 2 ).Conclusion: According to SUPAC guidelines formulation (F 5 ) containing combination of 15% HPMCK4M and 15% Xanthan gum, is the most identical formulation (similarity factor f 2 = 91.979,dissimilarity factor f 1 = 1.546 & No significant difference, t=0.0338) to marketed product (BENICAR).Best Formulation F 5 follows First order, Higuchi's kinetics, and the mechanism of drug release was found to be Non-Fickian Diffusion Anomalous Transport.(n=0.828).