Oxidative behavior of the sulfonamidic diuretic bumetanide at carbon paste electrode

Abstract

AbstractThe oxidative behavior of the 3‐(aminosulfonyl)‐5‐(butylamino)‐4‐phenoxy‐benzoic acid, Bumetanide, was studied in hydroalcoholic media (9:91 MeOH:H2O, pH range 1–9) and in two different ionic media (KNO3 and KCl) at a carbon paste electrode. The oxidation process has been shown to be irreversible and predominantly diffusion‐controlled over the entire pH range and in both media. A voltammetric method was developed at pH = 2.5 (phosphate buffer) and 0.4 M KNO3 for the quantitative determination of Bumetanide. The peak current was linear with the Bumetanide concentration in the range 2.74 × 10−6 M‐2.74 × 10−5 M with a detection limit of 4.39 × 10−7 M (0.16 ppm) and a reproducibility (in terms of relative standard deviation) of 3.61 and 7.60% for 10 determinations of 1.25 × 10−5 M and 4.99 × 10−6 M concentrations, respectively. The method for Bumetanide was applied to assays of pharmaceuticals (Fordiuran, 1 mg) and urine.