Simultaneous Determination of Simvastatin, Simvastatin Acid, Ramipril and Ramiprilate in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry

Abstract

A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of simvastatin and its in vivo generated drug simvastatin acid along with ramipril and its active metabolite ramiprilate in human plasma. After solid phase extraction (SPE) the analytes and IS were chromatographed on a hypurity C18 (150 mm × 4.6 mm i.d, 5 μm particle size) column using 50 μL injection volume with a run time of 6 min. An isocratic mobile phase consisting of 4 mmol/L ammonium acetate (pH 3.00): acetonitrile (20:80, v/v) was used to separate all these drugs. The precursor and product ions of these drugs were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring mode (MRM) with polarity switch. The proposed method was validated over the range of 0.25 ng/mL to 50 ng/mL for simvastatin and simvastatin acid, 0.25 ng/mL to 40 ng/mL for ramipril and 1.00 to 40 ng/mL for ramiprilate. Inter-batch and intra-batch precision (% CV) across 5 validation runs (LLOQ, LQC, MQC, HQC and ULOQ QC) was less than 14 for all the analytes. The accuracy determined for all the analytes at these levels was within ± 14 % in terms of relative error.