Development and validation of spectrophotometric methods for simultaneous estimation of furosemide and spironolactone in combined tablet dosage form

Abstract

A simple, economical, precise and accurate method for simultaneous determination of Furosemide and Spironolactone in combined dosage form has been developed. First order Derivative spectroscopy method (Method A) and Absorbance Ratio (Q-Absorbance) method (Method B) were used. The amplitudes at 350 nm and 250.80 nm in the first order derivative spectra were selected to determine Furosemide and Spironolactone, respectively and wavelength ranges 261.21 nm (iso-absorptive point) and 276 nm (λmax of Furosemide) were selected for Absorbance ratio (Q- Absorbance) method. Beer's law is obeyed in the concentration ranges of 2-10 μg/ml and 5-25 μg/ml for Furosemide and Spironolactone for Derivative method as well as Absorbance ratio method. The % assay for commercial formulation was found to be in the range 98.25% - 102% for Furosemide and 98.8-100.9 % for Spironolactone by the proposed methods. Recovery was found in the range of 98.25-100.00 for Furosemide and 100.88-101.46 % for Spironolactone by first order derivative spectroscopic method and 99.24-102% for Furosemide and 98.8-100.55% for Spironolactone by Absorbance ratio method for both the Formulations. The results of analysis have been validated statistically and recovery studies confirmed the accuracy and reproducibility of the proposed methods which were carried out according to ICH guidelines.