PREPARATION AND EVALUATION OF FLOATING TABLET OF METFORMIN HCL
Rehana Parveen* and Ranjeet Kumar Bhargav
ABSTRACT
The objective of the research work was to provide a gastroretentive
system for sustained release of metformin HCl in proximal part
gastrointestinal tract (GIT) in the form of oral floating tablet.
Metformin HCl is an anti-diabetic biguanid with poor bioavailability
and absorption window at the upper part of GIT. Floating tablets were
prepared by wet granulation method incorporating natural polymers
guar gum and k-Carrageen and a synthetic polymer HPMC K100
(HPMC) either alone or in combination. Sodium bicarbonate and citric
acid was used as gas generating agent. Floating tablets were evaluated
for weight variation, hardness, and friability, drug content, swelling
index, in vitro buoyancy and in vitro drug release study. The formulation optimized based on
floating ability, matrix integrity, and in vitro drug release in simulated gastric fluid pH 1.2.
Formulation prepared with combination of 6% w/w k-carrageen and 11%w/w guar gum
showed good gel strength, stable and persistent buoyancy for 12h, least floating lag time of
58 sec with good matrix integrity throughout dissolution period. The mechanism of drug
release was appears to be diffusion mechanism. Stability studies indicated absence of any
drug degradation on storage for 3 months at 40oC.
Keywords: Floating, Buoyancy, Gastro retentative, Sustained Release.
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