title: Development and validation of a sensitive, simple, and rapid method for simultaneous quantitation of atorvastatin and its acid and lactone metabolites by liquid chromatography-tandem mass spectrometry (LC-MS/MS).
abstract: The aim of the proposed work was to develop and validate a simple and sensitive assay for the analysis of atorvastatin (ATV) acid, ortho- and para-hydroxy-ATV, ATV lactone, and ortho- and para-hydroxy-ATV lactone in human plasma using liquid chromatography-tandem mass spectrometry. All six analytes and corresponding deuterium (d5)-labeled internal standards were extracted from 50 μL of human plasma by protein precipitation. The chromatographic separation of analytes was achieved using a Zorbax-SB Phenyl column (2.1 mm × 100 mm, 3.5 μm). The mobile phase consisted 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). All analytes including ortho- and para-hydroxy metabolites were baseline-separated within 7.0 min using a flow rate of 0.35 mL/min. Mass spectrometry detection was carried out in positive electrospray ionization mode, with multiple-reaction monitoring scan. The calibration curves for all analytes were linear (R(2) ≥ 0.9975, n = 3) over the concentration range of 0.05-100 ng/mL and with lower limit of quantitation of 0.05 ng/mL. Mean extraction recoveries ranged between 88.6-111%. Intra- and inter-run mean percent accuracy were between 85-115% and percent imprecision was ≤ 15%. Stability studies revealed that ATV acid and lactone forms were stable in plasma during bench top (6 h on ice-water slurry), at the end of three successive freeze and thaw cycles and at -80 °C for 3 months. The method was successfully applied in a clinical study to determine concentrations of ATV and its metabolites over 12 h post-dose in patients receiving atorvastatin.
authors.affiliation: Clinical Pharmacokinetics Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, 125 Fogarty Hall, 41 Lower College Road, Kingston, RI, 02881, USA.
authors.forename: Joyce S
authors.initials: JS
authors.lastname: Macwan
authors.forename: Ileana A
authors.initials: IA
authors.lastname: Ionita
authors.forename: Miroslav
authors.initials: M
authors.lastname: Dostalek
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Akhlaghi
mesh_terms: D000924:Anticholesteremic Agents / Q000008:administration & dosage / Q000097:blood* / Q000378:metabolism; D000069059:Atorvastatin; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006538:Heptanoic Acids / Q000008:administration & dosage / Q000097:blood* / Q000378:metabolism; D006801:Humans; D007783:Lactones / Q000097:blood* / Q000378:metabolism; D057230:Limit of Detection; D011758:Pyrroles / Q000008:administration & dosage / Q000097:blood* / Q000378:metabolism; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000924:Anticholesteremic Agents; D006538:Heptanoic Acids; D007783:Lactones; D011758:Pyrroles; D000069059:Atorvastatin