Continuous wavelet transform approach for the assay of active components in tablets

Abstract

Two continuous wavelets transform (CWT) methods were developed for the simultaneous determination of candesartan cilexetil (CAN) and hydrochlorothiazide (HCT) in tablets. The CWT methods were applied to the ratio spectra (RS) of the CAN and HCT. The CWT approaches based on the application of Haar and Mexican hat function (RS-HAAR-CWT and RS-MEXH-CWT, respectively) to the transformation of the ratio spectra were found to be suitable to reach a good spectral quantification. In the use of transformed ratio spectra, the calibration graphs for CAN and HCT were computed by using the RS-CWT-amplitudes at 244.5 and 264.5 nm in RS-HAAR-CWT spectra and at 255.6 and 250.0 nm in RS-MEXH-CWT spectra, respectively. The LOD and LOQ values for RS-HAAR-CWT and RS-MEXH-CWT were 0.39 - 0.58 and 0.43 - 0.33, 1.28 - 1.92 and 1.44 - 1.10 for CAN and HCT, respectively. The recovery results obtained by applying RS-HAAR-CWT and RS-MEXH-CWT calibrations to the artificial mixtures were found between 99.3 and 103.5% and obtained RSD values were found between 1.38 and 2.42. The validity and applicability of the CWT methods was performed by using the recovery study, standard addition technique and intra-day and inter-day tests. The proposed methods were successfully applied to the analysis of the CAN- HCT tablets.