Rapid and sensitive simultaneous determination of ezetimibe and simvastatin from their combination drug products by monolithic silica high-performance liquid chromatographic column.

A simple, precise and rapid high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of ezetimibe (EZE) and simvastatin (SIM) from their combination drug products. The applicability of monolithic LC phases in the field of quantitative analysis has been evaluated. The existing method with UV detection set at 240 nm was successfully transferred from a conventional silica column to a 10 cm x 4.6 mm i.d. monolithic silica column. By simply increasing the mobile phase flow rate, run time was about five-fold reduced and the consumption of mobile phase was about two-fold decreased, while the chromatographic resolution of the analytes remain unaffected. Ranitidine (RAN) was used as internal standard to guarantee a high level of quantitative performance. The method used a mobile phase consisted of acetonitrile-ammonium acetate (50 mM pH 5.0) (65:35, v/v). It was validated with respect to system suitability, specificity, limit of quantitation (LOQ) and detection (LOD), linearity, precision, accuracy, and recovery, respectively. The described method was linear over the range of 40-1200 ng ml(-1) (r=0.999) for both drugs. The LOD for EZE and SIM were 13.2+/-0.4029 and 13.3+/-0.4772 ng ml(-1), respectively. The LOQ were found to be 39.9+/-1.221 and 39.5+/-1.446 ng ml(-1) for EZE and SIM, respectively. The method is fast (less than 2.0 min) and is suitable for high-throughput analysis of the drug and ones can analyze 700 samples per working day, facilitating the processing of large-number batch samples.