Micro determination of enfenamic acid, piroxicam and naproxen in pharmaceutical preparations.
Foods & Drugs Laboratory, School of Chemistry, Andhra University, Waltair 530 003,
C SP Sastry Foods & Drugs Laboratory, School of Chemistry, Andhra University, Waltair 530 003
Simple, senstive and accurate spectrophotometric method for the quantitative determination of enfenamic acid (EA), piroxicam (PX) and naproxen [(NP), after demethylation] was developed based on the formation of a coloured oxidative coupling product with 2,6-dichloro0p0benzoquinone-4-chlorimine (gibbs reagent) in phosphate buffer (pH 7.0). The reaction is sensitive to permit the determination of 0.25 ppm of EA, 16 ppm of PX and 5 ppm of NP.