Simple,rapid and sensitive method for the determination of mefenamic acid in pharmaceutical preparations

Two simple and fast automated methods for the direct determination of mefenamic acid (MEF) in pharmaceutical samples are described. Continuous flow and stopped-flow systems with spectrophotometric detection of mefenamic acid with sodium nitroprusside and hydroxylamine hydrochloride were developed. Both methods show a good reproducibility (RSD < 1.5 and 1.8%, respectively) and a wide range of linearity (between 10–500 and 3–300 μg/mL). The stopped-flow protocol has a lower detection limit (1.2 μg/mL) with a sensitivity of about two times greater than the continuous flow technique. The proposed procedures are rapid, reliable and can be applied successfully to the estimation of mefenamic acid in different commercial forms.