Estimation of Furosemide Spectrophotometrically in Pharmaceutical preparations by Oxidative Coupling Reaction

Abstract

A simple, rapid and sensitive spectrophotometric method was described for the determination of Furosemide (FUR). The method is based on the oxidative coupling reaction between Furosemide and 1-Naphthylamine-4-sulfonic acid in the presence of potassium permanganate to form a yellow colored product with maximum absorptions at 465nm, which is soluble in water. Beer's law is obeyed in the concentration range of 3 to 23㎍.ml-1 with a molar absorptivity of 1.065×104 L.mol-1.cm-1, and Sandell's sensitivity of 0.0310㎍.cm-2, respectively. The correlation coefficient of 0.9994, with recovery average % of 99.948. Limit of detection (LOD), limit of quantification (LOQ) of 0.971㎍.ml- 1 and 3.237 ㎍.ml -1 and a relative standard deviation (RSD) % of 0.641 to 0.812. The proposed method has been used to successfully determine furosemide in pharmaceutical formulations (Tablet).