Spectrophotometric determination of two N-(4-quinolyl) anthranilic acid derivative (glafenine and floctafenine).

Spectrophotometric methods were developed for the determination of glafenine and floctafenine. The first method depends upon the determination of glafenine in raw material and tablets as well as in the presence of its main degradation product glafenic acid (up to 40%). Differential first derivative spectral response at 245 nm in 0.1 N hydrochloric acid, where the corresponding degradation product exhibits no contribution in 0.1 N sodium hydroxide. The method allows the determination of 2.5-30 microg ml(-1). The second method depends upon the reaction of floctafenine with 2,3-dichloro 5,6-dicyano-p-benzoquinone (DDQ) in acetonitrile to give highly colored complex that could be measured quantitatively at (about) lambda(max) 538 nm. The method permits the determination of 40-180 microg ml(-1) or by measuring the first derivative spectral response of the color at 610 nm. The method permits the determination of floctafenine in presence of thiocolchicoside. The methods mentioned both simplicity and sensitivity, having excellent precision and accuracy (100.31 +/- 0.63, 100.78 +/- 0.77 and 99.90 +/- 0.56 for glafenine and floctafenine, respectively). The results were of comparable accuracy and reproducibility with the reported methods.