Spectrophotometric investigations on protolytic equilibria of mefenamic acid and determination by means of Fe(III) in methanol-aqueous media.
Studies have been carried out on the effect of pH (from pH 11.33 to H(O) = -4.65) on the UV spectrum of mefenamic acid. The dissociation constant pKa was found to be 4.55 +/- 0.06 and the protonation constant pK(2) was -1.78 +/- 0.18 in methanol-aqueous media. Mefenamic acid was determined spectrophotometrically by formation of a coloured complex (2:5) with Fe(III). At 495 nm Beer's law was followed for the concentration range 96.52 to 579.12 mug ml(-1).
Zommer-Urbańska
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Department of Pharmaceutical Analysis, Medical Centre of Postgraduate Education, Debowa 3, 85-626 Bydgoszcz, Poland.
Bojarowicz
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