Dual Wavelength and Simultaneous Equation Spectrophotometric Methods for Estimation of Atenolol and Indapamide in Their Combined Dosage FormAuthor(s): N. Fernandes, M. S. Nimdeo, V. P. Choudhari, R. R. Kulkarni, V. V. Pande and A. G. Nikalje
Two simple, accurate and precise UV spectroscopic methods were developed for the simultaneous estimation of atenolol and indapamide in their combined dosage form. First method employs formation and solving of simultaneous equation using 246.4 nm and 266 nm as two wavelengths for formation of simultaneous equations. Second method being dual wavelength method, in which two wavelengths were selected for each drug in a way so that the difference in absorbance is zero for another drug. Atenolol has equal absorbance at 246.4 nm and 254.2 nm, where the differences in absorbance were measured for the determination of indapamide; similarly differences in absorbance at 266 nm and 270.2 nm were measured for the determination of atenolol. The results of analysis were validated statistically and by recovery studies and found to be free from interferences. These methods obey Beer’s law in the concentration range 100 to 350 and 5 to 17.5 μg/mL for atenolol and indapamide, respectively.