Abstract

Mefenamic acid (MA), a member of nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), has been widely use to relief pain and inflammation. Its medical uses are limited by poor aqueous solubility resulting in low bioavailability and gastric irritation. The aim of this study was to develop a mefenamic acid delayed-release matrix tablet formulation using solid dispersion (SD). Delayed-release drug delivery systems were designed to retard drug release in upper gastrointestinal tract avoiding gastrointestinal (GI) adverse reactions. SDs of MA were successfully prepared by solvent evaporation method employing methanol as a solvent. SDs incorporated surfactant and super disintegrant gave much higher rates of dissolution than SDs with combined carriers (PEG and surfactant), SD containing PEG and pure drug, respectively. The optimal SD containing MA:PEG4000:poloxamer188:crospovidone in the ratio 1:8:1:3 exhibited higher amount of drug release up to 8-fold compared with pure MA. FTIR and DSC were performed to identify the physicochemical interaction between drug and polymers. The resulting data justified that no change in the chemical structure of MA and the crystalline MA transformed into the amorphous state after preparation. The formulation F4 delayed-release tablet comprising SD of MA dissolved less than 4 % in artificial gastric fluid in the initial 2 h and released more than 95 % at 3 h in the artificial intestinal fluid. Accordingly, formulation F4 containing polyethylene oxide as a time-controlled matrix-forming polymer was a promising delayed-release solid dispersion system of MA.