Formulation and Evaluation of Metoprolol Tartrate Gastroretentive Floating Tablet Using Lannea Coromandelica Gum (Lannea Gum) as Natural Polymer

The objective of this work was to formulate and evaluate floating tablets of metoprolol tartrate with natural polymer Lannea coromandelica gum (Lannea gum) in comparison with synthetic polymer HPMC K100M. Metoprolol tartrate is used for the treatment of hypertension, angina pectoris, and cardiac arrhythmia. Its biological half-life is 3-4 hours, and it has a narrow absorption window. Different gastroretentive floating tablets of metoprolol tartrate were prepared using concentrations of Lannea gum ranging from 40% to 70% of the total weight of the tablet. For comparison, metoprolol tartrate gastroretentive floating tablets were also prepared using the synthetic polymer HPMC K100M with 70% concentration. The selected batches (F6, F7, F8 and F9) were evaluated for weight variation, thickness, friability, floating lag time, in vitro buoyancy time, drug content, and in vitro drug release kinetics. Formulation with L. coromandelica gum had shown better results than HPMC K100M. Based on the optimization process, F8 was selected, as it showed maximum drug release up to 12 hours, a buoyancy lag time of 3.1 minutes and the drug content was found to be 99.72%. Drug release from F8 followed first-order kinetics and the mechanism of release followed anomalous non-Fickian diffusion as the Peppas exponent value ‘n’ was in the range of 0.645 - 0.682 i.e. swelling followed by diffusion.