A fast, simple RP-HPLC and three spectrophotometric methods based on classical least squares (CLS), principle component regression (PCR) and partial least squares (PLS) calibrations were developed for simultaneous estimation of ramipril (RAMP) and atorvastatin calcium (ATOR) in formulations. The HPLC assay utilized Phenomenex - Luna RP C-18 (2) 250 x 4.6 mm 5 μm column with mobile phase composition of acetonitrile: 0.1 M sodium perchlorate (pH 2.5) (70 : 30, v/v), and flow rate of 1.5 mL/min with UV detection at 210 nm. Chemometric calibrations were constructed by using absorption data matrix corresponding to concentration data matrix, with measurements in the range of 201-270 nm (Δλ = 1 nm) in their zero-order spectra using 25 samples in training set. The chemometric numerical computations were realized using novel R-Software Environment (version 2.1.1). Reliability of predictions was validated for various ICH regulatory parameters. Both the results of proposed chemometric methods and that of proposed chromatographic method were compared and good agreement was found. Laboratory prepared mixtures and commercial tablet formulations were successfully analyzed by the developed methods.

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