Metformin HCl is an anti-hyperglycaemic agent having oral bioavailability of 52±5% due to its selective absorption from upper part of gastrointestinal tract. It has biological half-life of 1.74±0.2 hours, hence the development of floating sustained release drug delivery system is recommended in order to enhance the bioavailability. The high dose of metformin HCl in the form of SR dosage form results in increased tablet weight and dimensions making the dosage form difficult to be swallowed by the patient. The present investigation deals with use of minimum proportions of natural polymers for drug release control by utilizing the advantage of interactions of gums resulting in enhanced matrix strength.
Xanthan gum a heterodisperse system produces a highly ordered, helical or double helical molecular conformation and homodisperse system of locust bean gum is slowly soluble and ungelled at low temperatures. The xanthan gum component acts to produce a faster gelation of the homopolysaccharide component and the homopolysaccharide acts to cross-link the normally free heteropolysaccharide helices resulting in increased viscosity. The interaction of Xanthan and locust bean gum was confirmed by FT-IR spectroscopy and differential scanning calorimetry. Drug release from optimized batch containing metformin HCl: HPMC K100M in 1:1 and sodium bicarbonate 5, 10, 15% ratio has sustained the drug release for 12 hours. Metformin HCl: HPMC K100M in 1:1 and sodium bicarbonate 5, 10, 15% ratio with citric acid. Metformin: in combination of Xanthan and locust bean gum (2:8 optimum viscosity for synergism) in 1:0.5, 1:0.75 and 1:1 ratio with 5, 10, 15% sodium bicarbonate. Metformin: in combination of Xanthan and locust bean gum (2:8 optimum viscosity for synergism) in 1:0.5, 1:0.75 and 1:1 ratio with sodium bicarbonate and citric acid in 5, 10, 15% ratio respectively sustained the drug release upto 12 hours.
Cite this article:
P.S. Salve. Development and in vitro evaluation of gas generating floating tablets of metformin hydrochloride. Asian J. Res. Pharm. Sci. 1(4): Oct.-Dec. 2011; Page 105-112.