Net analyte signal-based methods for the simultaneous determination of paracetamol, propyphenazone and caffeine by UV spectrophotometry

© 2018 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.Three different net analyte signal-based (NAS) methods - NAP CLS, HLA/GO and HLA XS were successfully applied for the determination of ternary mixtures of paracetamol (PAR), propyphenazone (PRO) and caffeine (CAF). The methods used absorbance UV-spectral data for resolving this complex system with overlapping drug spectra. A reduced five-level orthogonal design was used for the formation of a calibration set including the three compounds. The chemometric models were tested on an external validation dataset with concentrations within the calibration range. All proposed chemometric algorithms could be successfully applied for the determination of the above compounds in the pharmaceutical tablet formulation Saridon®. The obtained results showed that the NAS performance was similar compared to partial least-squares method (PLS-1). In addition, the use of the net analyte signal concept allowed the calculations of the analytical figures of merit. A moving window wavelength selection strategy was used, which significantly reduced the number of factors and improved the analytical recoveries