Development and evaluation of floating tablet of metoprolol succinate for increased bioavailability

The present study is based on development and evaluation of gastroretentive floating tablets of metoprolol succinate by direct compression method, to increase the oral bioavailability of MS. For this, we used a combination of two different hydrophilic polymers that is polyethylene oxide PEO N-80 (X1) and hydroxy ethylcellulose HEC (X2) as independent variables and studied its effect on drug release (as dependent variable) at 20h for MS. A 3 2 factorial design was used for optimization purpose. The DSC result shows no interaction between two polymers and the drug (MS). Further, in vitro drug release studies have shown a sustained drug release for more than 20h in upper gastrointestinal region (stomach). In vivo study using rabbits have shown increased AUC 0-24 (bioavailability) of prepared optimized F6 formulation as compared to the marketed sustain release tablet of MS. Stability study shows no comparable differences on physical parameters and the drug release after 3 months of accelerated stability testing.  Hence, we can conclude that a floating tablet containing combination of hydrophilic polymers can be used for gastric retention for more than 20hr which will increase the oral bioavailability of MS.