A simple assay for the simultaneous determination of rosuvastatin acid, rosuvastatin-5S-lactone, and N-desmethyl rosuvastatin in human plasma using liquid chromatography–tandem mass spectrometry (LC-MS/MS)

• Published in: Analytical and bioanalytical chemistry 2012, Vol.402 (3), p.1217-1227
• Main Authors: Macwan, Joyce S., Ionita, Ileana A., Akhlaghi, Fatemeh
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Assaying; Biochemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Chromatography; Chromatography, Liquid - economics; Chromatography, Liquid - methods; Fluorobenzenes - blood; Food Science; Human; Humans; Laboratory Medicine; Lactones - blood; Liquids; Mass spectrometry; Methyl alcohol; Monitoring/Environmental Analysis; Original Paper; Pyrimidines - blood; Rosuvastatin Calcium; Sensitivity and Specificity; Solvents; Sulfonamides - blood; Tandem Mass Spectrometry - economics; Tandem Mass Spectrometry - methods
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-011-5548-4

A simple and sensitive assay was developed and validated for the simultaneous quantification of rosuvastatin acid (RST), rosuvastatin-5 S -lactone (RST-LAC), and N -desmethyl rosuvastatin (DM-RST), in buffered human plasma using liquid chromatography–tandem mass spectrometry (LC-MS/MS). All the three analytes and the corresponding deuterium-labeled (d6) internal standards were extracted from 50 μL of buffered human plasma by protein precipitation. The analytes were chromatographically separated using a Zorbax-SB Phenyl column (2.1 mm × 100 mm, 3.5 μm). The mobile phase comprised of a gradient mixture of 0.1% v / v glacial acetic acid in 10% v / v methanol in water (solvent A) and 40% v / v methanol in acetonitrile (solvent B). The analytes were separated at baseline within 6.0 min using a flow rate of 0.35 mL/min. Mass spectrometry detection was carried out in positive electrospray ionization mode. The calibration curves for all three analytes were linear ( R  ≥ 0.9964, n  = 3) over the concentration range of 0.1–100 ng/mL for RST and RST-LAC, and 0.5–100 ng/mL for DM-RST. Mean extraction recoveries ranged within 88.0–106%. Intra- and inter-run mean percent accuracy were within 91.8–111% and percent imprecision was ≤15%. Stability studies revealed that all the analytes were stable in matrix during bench-top (6 h on ice–water slurry), at the end of three successive freeze and thaw cycles and at −80°C for 1 month. The method was successfully applied in a clinical study to determine the concentrations of RST and the lactone metabolite over 12-h post-dose in patients who received a single dose of rosuvastatin. Figure A typical chromatogram depicting the peaks of rosuvastatin acid (RST), rosuvastatin-5 S -lactone (RST-LAC), and N -desmethyl rosuvastatin (DM-RST) and their respective internal standards