Assessment of different partial least squares variants for determination of binary-drug system exhibiting intense spectral overlap

Amoxicillin (AMO) and clavulanic acid (CLA) are popular activate pharmaceutical ingredients that are widely used due to their efficient medical activity. However, this binary system suffers from intense spectral overlap (93.6%). Inspite of the intense spectral overlap and serious nonlinearity in the current system, both drugs were accurately quantified by multivariate calibration. The performance of different partial least squares PLS variants (NIPALS, SIMPLS, Kernel and Bidiagonalization) for accurate quantification of AMOMO-CLA in commercial formulation was outlined. Partial response and partial residual plots confirmed a serious nonlinearity in the binary system. Compared to other algorithms, PLS-Kernel exhibited a better performance for drugs quantification and seven latent variables were necessary for accurate quantification: 94.0(9.6%) and 95.6(5.2%) for AMOMO and CLA, respectively. The intense spectral overlap, nonlinearity, and non-modelled excipients are effectively handled by PLS-Kernel calibration.