Simultaneous resolution of a binary mixture of captopril and hydrochlorothiazide in tablets by bivariate and multivariate spectral calibrations

The multivariate spectral calibration methods, two-linear regression-calibration (bivariate calibration (BC)) and multi-linear regression-calibration (MLRC) are proposed for the simultaneous resolution of a binary mixture of hydrochlorothiazide (HCT) and captopril (CTP), which have closely overlapping spectra. The BC and MLRC calibration algorithms are described for the two-component system, HCT-CTP. Some alternative methods, classical least squares (CLS), inverse least squares (ILS), principal component regression (PCR) and principal least squares (PLS) methods, were also used to determine HCT and CTP in the mixture. Using a synthetic mixture of the two drugs, all the methods were validated and applied to tablets. The BC and MLRC methods which are very rapid, and easy to apply, yet not expensive, are powerful tools with very simple mathematical contents for the quantitative analysis. Data treatment was performed using MAPLE V, EXCEL and SPSS 10.0 Software.