Simultaneous Spectrophotometric Determination of Levamizole and Oxyclozanide in Bolus by the Bivariate and Multivariate Linear Regression Calibration Methods

Abstract

Bivariate- and multivariate-calibration methods were improved for the simultaneous spectrophotometric determination of levamizole (LEV) and oxyclozanide (OXY) in commercial veterinary formulation without requiring chemical pretreatment and spectrophotometric graphical procedure. The bivariate calibration (BC) was constructed by using four linear regression equations at two-wavelength pair (218and 250 nm) for each compound. The selection of the optimal two-wavelength pair for the application of the BC method was performed by using the Kaiser's technique. The multivariate calibration (MC) was obtained by the simultaneous use of the 36 linear regression equations at the nineteen-wavelengths set from 216 nm to 254 nm in the spectral wavelength region of 200-290 nm. This MC method does not require any selection treatment of the optimal wavelength set. The BC and MC methods were validated by analyzing various synthetic binary mixtures and by using the standard addition technique. The successful determination results were reported for the quantitative estimation of the commercial veterinary product of the related active compounds.