FRACTIONAL WAVELET METHOD FOR THE SIMULTANEOUS QUANTITATIVE ANALYSIS OF LACIDIPINE AND ITS PHOTODEGRADATION PRODUCT

Qualitative and quantitative analysis of drug and its degradation products with impurities during the pharmaceutical development process and after market is one of important problems of the analytical chemistry and drug industry. For this reason new methods for quantitative analysis should be developed. One of these new and promising methods is fractional wavelet transform (FWT). In this study FWT was applied to the original absorption spectra of lacidipine (LAC) and its photodegradation product (LACD) and the resulting FWT spectra were processed by continuous wavelet transform (CWT). This method doesn’t requires any chemical separation step and chemical complex reaction to obtain a detectable signal for the degradation product. By using the Mexican hat function, the calibration functions for LAC and LACD were obtained by measuring the CWT transformed signals at 461.1 nm for LAC and 414.6 nm for LACD, after FWT processing of the original absorption spectra. The calibration graphs were linear in the concentration range of 5.08-40.64 for LAC and 0.51-8.16 for LACD and the limit of detection (LOD) and the limit of quantitation (LOQ) were found as 0.289 and 0.956 g/mL for LAC and 0.036 and 0.118 g/mL for LACD respectively. The proposed approach was applied to the quantitative evaluation of LAC and LACD in samples and satisfactory results were obtained.