Design and evaluation of floating drug delivery systems of Metformin with natural gums as release retarding polymers

Abstract

Metformin hydrochloride floating tablets were prepared by wet granulation method by using optimized concentrations of gas generating agents, binding agents and natural gums as polymers like gum kondagogu and gum karaya. The formulations F1-F4 with concentrations 2-3.5% were prepared to optimize binding agent and formulations F5-F7 with concentrations 15-20% to optimize gas generating agent where optimum percentage of binding agent was found around 2.3% and gas generating agent was found around 17.25% to get quick floating lag time. The prepared granules evaluated for various parameters showed good results in which the Carrs index, hausner ratio and angle of repose, the values were found in between 9.05-16.78, 1.02-1.46 and 23.17-32.64 respectively. All compressed formulations were evaluated for various parameters and results of hardness, friability, drug content, were found around 7.1-8.8kg/cm2, 0.56-1.48% and 499.3-499.8mg respectively. The tablets prepared by these granules of two natural gums as polymers showed desired floating properties. F6 formulation containing gum kondagogu and F11 formulation containing gum karaya showed good release retardation with release 99.42% and 99.75% respectively after 12 hours in in vitro drug release studies. Formulations F6 and F11 after stability studies showed good results proving stable. In vivo studies also showed good correlation with the results of in vitro and X-ray pictograms proved the formulations is stable in vivo. Formulations F6 and F11 contains natural gums Kondagogu and karaya with 17.25% concentration were considered as best formulation as they showed good release retardation and, in release kinetic studies the n-value found appropriate for controlled release formulations.