Simultaneous Determination of Hydrochlorotiazide and Olmesartan Modoxomil in a Binary Mixture by the Calibrations of the Spectral Linear Regression Equations

Abstract

Two new approaches were proposed for the quantitative analysis of the commercial samples consisting of hydrochlorotiazide (HCT) and olmesartan modoxomil (OLM). The proposed bivariate calibration (BC) and multivariate linear regression calibration (MLRC) methods are based on the simultaneous use of the linear regression equations for each compound. The UV absorption spectra of calibration solutions in the linear concentration range of 1.0-16.0 mu g/mL for both HCT and OLM were recorded between the 200-300 nm wavelength regions. The individual linear regression equations of the subjected compounds were obtained by using the relationships between the concentration and absorbance values at the 62 wavelength points with the interval of 1.0 nm from 218 nm to 279 nm. The BC and MLRC model based linear regression equations were validated by analyzing the binary mixture samples containing HCT and OLM in the different concentration compositions. The proposed BC and MLRC approaches were found to be accurate, precise and rapid for the simultaneous determination of HCT and OLM in combined dosage form.