Cumulative area pre-processing (CAP): a new treatment of UV data for the analysis of complex pharmaceutical mixtures.

A new approach to pre-processing of the UV spectral data in combination with chemometric techniques, aiming to obtain a significant amplification of the analytical information, is proposed. The single areas under the curve between two consecutive wavelengths were calculated along the full spectrum and therefore their cumulative sum was carried out. The method was called "cumulative area pre-processing" (CAP) and applied to multicomponent pharmaceutical formulations to test its performance in improving the accuracy of the analysis. The proposed procedure has demonstrated high ability in the quantitative determination of the components present in very low amount compared to other. Three multicomponent drug formulations were analyzed by applying the partial least squares (PLS) algorithm to the UV data processed by CAP and the results compared with those carried out by using the same data without treatment and after derivative transformation. The best results in the determination of the components present in lower concentrations were obtained by applying the PLS models calculated on data processed by CAP and confirmed in the analysis of marketed drug products.