ABSTARCTObjectives: Metforminhydrochloride is a potent, biguanide antihyperglycemic agent generally recommendedas a first line drug for the treatment of diabetes mellitus (type II). Thepurpose of the present work is to formulate and characterize sustained release coatedmatrix granules of Metformin hydrochloride. Methods: Metforminhydrochloride granules were prepared using ethyl cellulose as release retardantby mixing the powder blend in a V – cone blender and wetting it with aqueoussolution of HPMC K100. The prepared granules (MG1-MG5) were investigated for drugrelease data. The granules which an exhibited extended release up to 4hrs werecoated in a standard coating pan with blends of Eudragit RS and RL to furtherenhance release period and marked as CMG3 and CMG4 which were later filled intoempty capsules.
The granules were evaluated for micromeretic properties andcharacterized for percentage yield, percent drug content, particle sizedistribution and in vitro release ofthe drug.Results: Allthe formulations showed percentage yield in the range of 77.66 to 82.86% anddrug content in the range of 78.23 to 96.62%. CMG3 showed drug release of97.02% for 12 hrs.
FTIR and DSC studies indicated that no possible interactionexisted between the drug and the polymers used. SEM images showed that thegranules were spherical in shape with smooth surface and completely coveredwith a coating of polymer. Kinetic analysis of drug release confirmed that drugrelease followed zero order kinetics where it is independent of theconcentration. Conclusion: Fromthe results it was analyzed that design of coated granules employing thepolymers used in the present work can produce a sustained release of the drugover a period of 12hrs.
Keywords: metformin, sustainedrelease, V- cone blender, Eudragit, standard coating pan INTRODUCTIONThedesign of sustained release dosage forms is to slowly release the drug over an extendedtime period. They possess a major advantage of improved patient compliance asthe dosing frequency is once or twice daily.1 In case of dosage forms for extended release, multiple unitforms are mostly preferred over single unit dosage forms as they contain minuteamount of the drug and thus have lower risk of dose dumping.2Metformin hydrochloride is a potent anti-diabeticdrug with a major drawback of shorter elimination half-life (6.2 hrs.
). It actsin the presence of insulin to enhance glucose use and decrease production of glucosetheir by counteracting insulin resistance. The effect of metformin includes enhancedglucose uptake and its and reduced hepatic gluconeogenesis. Drugs with shorterbiological half-life are suitable candidates for formulation in sustained releasedosage forms. 3-4The aim of the current investigation is to formulatecoated granules of Metformin hydrochloride.
In order to overcome the drawbackof shorter biological half-life and fluctuation in plasma level concentration ofthe drug, an attempt was made to sustain the release of the drug by formulatingit as coated granules using retardant polymers.