Permanganometric determination of etamsylate in bulk drug and in tablets

Abstract

One titrimetric and two spectrophotometric methods which are simple, selective, sensitive, accurate, precise and economical for the determination of etamsylate (ETM) in bulk drug and in tablets employing permanganate as the oxidimetric reagent are described. In titrimetry, ETM is titrated directly with permanganate in sulphuric acid medium. A direct spectrophotometry (method A) involves treating the aqueous solution of the drug with permanganate in alkaline medium and measuring the bluish green product at 610 nm. In indirect spectrophotometry (method B), the drug solution was treated with a fixed concentration of permanganate in H2SO4 medium, and after a specified time, the unreacted permanganate was measured at 545 nm. The molar combining ratio in titrimetry and the optimum assay conditions were studied. Titrimetry is applicable over 1-10 mg range and the calculations are based on a 1:4 (ETM:KMnO4) molar ratio. In spectrophotometry, Beer's law is obeyed over 0.5- 5.0 and 1.5-15 ?g ml-1 for method A and B, respectively. The molar absorptivity values are calculated to be 2.79?104 and 4.17?104 l mol-1 cm-1 for method A and B, respectively and the corresponding sandell sensitivity values are 0.0094 and 0.0063 ?g cm-2. The limits of detection (LOD) and quantification (LOQ) are also reported for spectrophotometric methods. The applicability of the developed methods was demonstrated by the determination of etamsylate in pure drug as well as in commercial dosage forms.