A New Application of Chemometric Techniques to HPLC Data for the Simultaneous Analysis of a Two‐Component Mixture

Abstract A new chemometric approach using high performance liquid chromatography (HPLC) with photodiode array (PDA) detection was developed and applied to the simultaneous determination of enalapril maleate (EA) and hydrochlorothiazide (HCT) in tablets. Chemometric calibration techniques, classical least squares (CLS), principle component regression (PCR), and partial least squares (PLS) were subjected to the peak area at multiwavelength PDA detector responses. The combination of HPLC and chemometric calibration techniques was called HPLC‐CLS, HPLC‐PCR, and HPLC‐PLS. For comparison purposes, the HPLC method called classical HPLC method was used for the confirmation of the results obtained from combined HPLC‐chemometric calibration techniques. A good chromatographic separation between two drugs and internal standard (IS) was achieved using a Waters Symmetry® C18 Column 5 µm 4.6×250 mm and a mobile phase consisting of 0.2 M acetate buffer and acetonitrile (v/v, 60∶40). The multiwavelength PDA detection was done at 230 (A), 240 (B), 250 (C), 250 (D), 240 (E) nm wavelengths, and peak area was recorded for the concentration set in the mobile phase. Three HPLC‐chemometric calibrations and a classical‐HPLC method were tested by analyzing the synthetic mixture of EA and HCT in the presence of losartan potassium (IS). The proposed methods were applied to real samples containing the present two drugs. The obtained results were statistically compared with each other.