The present research work was concerned with the development of effervescent floating matrix tablets of mefenamic acid. Matrix tablets were prepared by wet granulation method by using synthetic swelling polymers like HPMC K4M, HPMC K15M and HPMC K100M for ascertaining the best possible polymer. Sodium bicarbonate and citric acid was incorporated as gasgenerating agent. The prepared tablets were evaluated in terms of their pre-compression and post-compression parameters. The formulations were optimised for different viscosity grades of HPMC and its concentration using central composite design by taking HPMC K4M, HPMC K15M and HPMC K100M as independent variables and floating lag time, floating time and 90% drug release as dependent variables respectively. Pre-compression and post-compression studies of preliminary trials and initial optimised formulations were within the specified limits. The final optimised formulations containing HPMC K4M (OFT1) showed floating lag time of 46 sec, floating time of 24 h and maximum drug release of 95.08% when compared to the formulations containing HPMC K15M (OFT2) and HPMC K100M (OFT3) with floating lag time of 68 sec and 120 sec, floating time of 24 h and drug release of 92.04% and 81.14%. Respectively. The results of pre-compression and post-compression parameters of final optimised were within the specified limits. The accelerated stability studies of the final optimised formulations indicated no appreciable change in drug content and in vitro drug release rates of the formulations. Thus, it can be concluded that with increase in polymer concentration and increased viscosity grade of HPMC the drug release of mefenamic acid can be sustained by promoting extended gastric residence and buoyancy.
Sustained Release, Mefenamic acid, Floating lag time, Floating time
