Abstract
Derivative calculation is a powerful technique used in analytical chemistry to resolve spectra, sharpen peaks and carry out quantitative analysis. Three different derivative calculation methods have been used in this paper for the simultaneous determination of ambroxol hydrochloride (AMB) and doxycycline (DOX) in their binary mixture. These methods are numerical differentiation (ND), Savitzky-Golay (SG) and continuous wavelet transform methods (CWT). In these methods, calibration curves were linear in the range of 6-40 mu g ml(-1) for AMB and 4-32 mu g ml(-1) for DOX (r in all methods not less than 0.9996). The measurements were carried out at 245, 246, 247 and 259 nm for AMB and 372, 373 and 376 nm for DOX. The proposed three methods are rapid, simple, sensitive and accurate. No preliminary separation steps or resolution equations are required; thus they can be applied for the simultaneous determination of AMB and DOX in ambrodoxy capsules in quality control laboratories.