Photochemical properties of simvastatin and lovastatin induced by radiation

HPLC and UV spectrophotometry were developed and validated for quantitative determination of two antihiperlipoproteinemia drugs, lovastatin and simvastatin. Analytical performance parameters such as linearity, precision, specificity, limit of detection (LOD) and limit of quantification (LOQ) were determined according to the ICH Q1B guidelines. Chromatography was carried out by isocratic technique on a reversed-phase C-18 column. The UV spectroscopy determinations were performed at 238 nm. The linearity of the calibration curves in the desired concentration range was good (r(2)> 0.999) for both HPLC and UV methods. The relative standard deviation (RSD) for these methods was < 5%. Moreover, the precision obtained with HPLC correlated well with the UV results. The methods proposed are highly sensitive and precise. Other methods used for assessment of the photostability of the substances studied were electron paramagnetic resonance (EPR) and differential scanning calorimetry (DSC).