Monitoring of Simvastatin impurities by HPLC with microemulsion eluents

The use of microemulsions as eluents in HPLC has shown excellent potential. We have developed a novel approach for the analysis of Simvastatin and its six impurities, applying microemulsions as mobile phase. The method was validated and applied to the analysis of commercially available tablets in order to confirm that the proposed approach is useful for the application of this technique to drug analysis. A microemulsion eluent containing 0.9% w/w of diisopropylether, 1.7% w/w of sodium dodecyl-sulphate (SDS), 7.0% w/w of co-surfactant such as n-butanol and 90.4% w/w of aqueous 25 mM di-sodium phosphate pH 7.0 was used for the analysis. Separations were performed on a 3.5 mu m X Terra(TM) 50 x 4.6 mm column at 30 degrees C. Detection was performed at 238 nm with an eluent flow rate of 0.3 mL min(-1). The optimized and validated method can be used for the identification and simultaneous determination of Simvastatin and its six impurities in bulk drug and in pharmaceutical dosage forms.