Formulation and Evaluation of Sustained Release Matrix Tablets of Metformin Hydrochloride Using pH Dependent and pH Independent Methacrylate Polymers.
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Date
2011-04
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Abstract
Metformin hydrochloride is recommended globally as first line therapy due to its favorable
profile on morbidity and mortality associated with type-2 diabetes mellitus. However,
limitations of multiple dosing and risk of triggering gastrointestinal symptoms make its
dose optimization difficult. Extended-release metformin matrix tablets were prepared by
direct compression of drug and different pH-dependent (Eudragit L-100 and S-100) and
pH-independent (Eudragit RLPO and RSPO) polymer combinations. The influence of
varying the polymer/polymer (w/w) ratio was evaluated. Among the different examined
polymer blends, matrix tablets based on S-100/RLPO and S-100/RSPO mixtures gave
the more sustained release pattern. The excipients used in this study did not alter
physicochemical properties of the drug, as tested by Fourier transform Infrared
Spectroscopy and the thermal analysis using differential scanning calorimetry. All the
batches were evaluated for thickness, weight variation, hardness, and drug content
uniformity. The in vitro drug dissolution study was carried out using USP 22 apparatus II,
paddle method and the release mechanisms were explored. Mean dissolution time is
used to characterize drug release rate from a dosage form and indicates the drug release
retarding efficiency of polymer. Kinetic modeling of in vitro dissolution profiles revealed
the drug release mechanism ranges from diffusion controlled to anomalous type. Fitting
the data to Korsmeyer equation indicated that diffusion along with erosion could be the
mechanism of drug release.
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Keywords
Metformin hydrochloride, extended release matrix tablet, pH-independent polymers,, pH-dependent polymers, release kinetics
Citation
Wadher Kamlesh J, Kakde Rajendra B, Umekar Milind J. Formulation and Evaluation of Sustained Release Matrix Tablets of Metformin Hydrochloride Using pH Dependent and pH Independent Methacrylate Polymers. British Journal of Pharmaceutical Research. 2011 Apr-Jun; 1(2): 29-45.