Formulation and Evaluation of Sustained Release Tablets of Ibuprofen and Metformin

Abstract

Conventional oral drug formulations often require multiple daily doses to sustain therapeutic plasma concentrations, which reduces patient adherence and increases the likelihood of adverse effects caused by fluctuating drug levels. This study aimed to design, develop, and characterize matrix-type sustained release (SR) tablets incorporating two clinically important drugs — Ibuprofen, a nonsteroidal anti-inflammatory agent, and Metformin hydrochloride, an oral antidiabetic biguanide — using hydrophilic polymers such as hydroxypropyl methylcellulose (HPMC K100M) and carboxymethylcellulose (CMC) as primary release-retarding excipients.
Ten formulations of Ibuprofen SR tablets (F1–F10) and four formulations of Metformin SR tablets (F1–F4) were prepared by direct compression. Preformulation parameters including bulk density, tapped density, Carr's compressibility index, angle of repose, and drug–excipient compatibility were evaluated. Post-compression evaluation encompassed weight variation, hardness, friability, disintegration time, drug content uniformity, and in-vitro dissolution profiling over 12 hours.
All formulations demonstrated acceptable physicochemical properties. Drug release followed a sustained, near-zero-order pattern, with Ibuprofen releasing approximately 96% and Metformin approximately 98% of the labeled dose by the end of 12 hours. Higher polymer concentrations markedly extended disintegration time (up to 90 min for F4) and slowed drug release, confirming that HPMC concentration is the primary determinant of release kinetics. These findings suggest that the optimized formulations hold significant potential for once or twice-daily oral delivery, improving therapeutic outcomes and patient compliance for chronic inflammatory and metabolic conditions.

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