Analytical Utility of Potassium Permanganate for the Assay of Albendazole in Bulk Drug and Pharmaceuticals

Two rapid, simple, sensitive and cost-effective titrimetric and spectrophotometric methods are described for the determination of albendazole (ALB) in bulk drug and in pharmaceuticals. In titrimetry (method A), ALB is oxidized by a known excess of potassium permanganate (KMnO4) in H2SO4 medium followed by the determination of unreacted permanganate by titration with ferrous ammonium sulphate (FAS). In spectrophotometry (method B), ALB is treated with a measured excess of permanganate in acid medium and the unreacted oxidant is measured at 545 nm. The molar ratio (stoichiometry) in titrimetry and the optimum assay conditions are studied. Titrimetry is applicable over 2-9 mg range and the calculations are based on a 1:1 (ALB: KMnO4) molar-ratio. In spectrophotometry, Beers law is obeyed over 8.0-64.0 μg mL-1 concentration range of ALB. The molar absorptivity and Sandell sensitivity values are calculated to be 3.348 × 103 L mol-1 cm-1 and 0.08 μg cm-2, respectively. The limits of detection (LOD) and quantification (LOQ) are also reported for the spectrophotometric method. The applicability of the developed methods is demonstrated by the assay of ALB in pure drug as well as in commercial formulations.