A Stability-Indicating RP-LC method for the Determination of Related Substances in Simvastatin
A gradient reverse-phase liquid chromatographic (RP-LC) method was developed for the determination of related substances in Simvastatin drug substance. Simvastatin is a potent competitive inhibitor of HMG-CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis, can be used in treatment of hypercholesterolemia. Good chromatographic separation was achieved for all the listed known impurities along with some new process impurities from the peak of interest. The current USP HPLC method for the determination of related substances of simvastatin is not able to well separate some critical impurities that may form during the synthetic process or carried over from the starting materials. The chromatographic separation achieved on a ZORBAX column. The LC method employs solutions A and B as mobile phase. PDF