Validation and application of high-performance liquid chromatographic and spectrophotometric methods for simultaneous estimation of nebivolol and hydrochlorothiazide: a novel approach to multivariate calibrations by R-Software Environment.

A fast, simple reversed-phase HPLC method and two spectrophotometric methods based on principal component regression and partial least squares calibrations were developed for determination of nebivolol (NEB) and hydrochlorothiazide (HCTZ) in formulations without prior separation or masking. The HPLC assay utilized a Phenomenex-Luna RP-18(2) 250 x 4.6 mm, 5 microm column with acetonitrile--0.

Simultaneous quantitative resolution of atorvastatin calcium and fenofibrate in pharmaceutical preparation by using derivative ratio spectrophotometry and chemometric calibrations.

In the present work, five different spectrophotometric techniques for simultaneous determination of formulations containing atorvastatin calcium (ATOR) and fenofibrate (FENO) in various combinations are described. In ratio spectra derivative spectrophotometry, analytical signals were measured at wavelengths corresponding to either maximums or minimums for both drugs in first derivative spectra of ratio spectra obtained by using either spectrum as divisor. For the remaining four methods using chemometric techniques, namely, classical least squares (CLS), inverse least squares (ILS), principal component regression (PCR) and partial least squares (PLS), the calibrations were constructed by using the absorption data matrix corresponding to the concentration data matrix, with measurements in the range of 231 - 310 nm (Deltalambda = 1 nm) in their zero-order spectra.