Floating Matrix Tablet of Metformin Hydrochloride Using Natural Polymers

The purpose of the study was to prolong the gastric residence time of  metformin hydrochloride  by designing its floating tablets and to study the influence of natural polymers like okra gum and fenugreek  gum on its release rate. Sodium bicarbonate was added as a gas generating agent that releases carbon dioxide in the gastric acidic environment which helped in maintain the buoyancy. Metformin hydrochloride  is a biguanide glucose-lowering agent that has been widely used in the management of NIDDM, whose hyperglycemia cannot be satisfactorily managed on diet alone. Metformin hydrochloride is incompletely absorbed from GI tract, with an absorption window confined to the upper part of GI tract. It also has a half life of about 2 hours and its absolute bioavailability is reported to be about 50-60% of the administered oral dose. An obstacle to the more successful use of metformin hydrochloride therapy is the high incidence of GI symptoms seen in about 30% patients, especially during initial weeks of treatment. Patient compliance decreases with frequent dosing regimen and side effects associated with the same. In order to optimize therapy research efforts have been focused on the development of oral sustained release (SR) preparations using natural polymers as well as controlled release gastroretentive dosage forms. The present study outlines a systematic approach for the development of hydrodynamically balanced tablet of metformin hydrochloride using natural polymers with a view to enhance its oral bioavailability and efficacy. Development of floating matrix tablets of metformin hydrochloride using natural polymers (okra and fenugreek).Comparative studies of both available marketed formulations and HPMC polymer.