Evaluation of impurities in simvastatin drug products with the use of FT-IR spectroscopy and selected chemometric techniques

In the present study a reversed phase high performance liquid chromatography (RP-HPLC) method with diode array detector (DAD) at room temperature was used for obtaining impurity profiles of 20 drug products containing simvastatin as an active substance. Fourier-transform infrared spectroscopy (FT-IR) was carried out to obtain absorption spectra of samples. The partial least squares (PLS) model was built to predict the relative content of lovastatin, the main impurity of simvastatin, and sum of statin-like impurities. In order to build the PLS model, peak areas obtained from HPLC chromatograms were related to FT-IR spectra of drugs. The PLS model based on signal normal variate and orthogonal signal correction (SNV+OSC) transformed FT-IR spectra was able to predict the content of drug impurities in real samples with a good prediction ability (R 2 > 0.95).