Determination of 2-methoxyestradiol in human plasma, using liquid chromatography/tandem mass spectrometry.
A liquid chromatography/tandem mass spectrometric (LC/MS/MS) assay was developed for the quantitative determination of 2-methoxyestradiol (2ME2) in human plasma. Sample pretreatment involved liquid-liquid extraction with ethyl acetate of 0.3-mL aliquots of plasma spiked with the internal standard, deuterated 2ME2 (2ME2-d5). Separation was achieved on a Zorbax Eclipse C18 column (2.1 x 50 mm, i.d., 5 microm) at room temperature using a gradient elution with methanol and water at a flow rate of 0.25 mL/min. Detection was performed using atmospheric pressure chemical ionization MS/MS by monitoring the ion transitions from m/z 303.1 --> 136.8 (2ME2) and m/z 308.1 --> 138.8 (2ME2-d5). Calibration curves were linear in the concentration range of 1-100 ng/mL. The accuracy and precision values, obtained from three different sets of quality control samples analyzed in quintuplicate on four separate occasions, ranged from 105-108% and from 3.62-5.68%, respectively. This assay was subsequently used for the determination of 2ME2 concentration in plasma of a patient with cancer after a single oral administration of 2ME2 at a dose of 2200 mg.
Lakhani
Nehal J
NJ
Clinical Pharmacology Research Core, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
Lepper
Erin R
ER
Sparreboom
Alex
A
Dahut
William L
WL
Venitz
Jürgen
J
Figg
William D
WD
D000077584:2-Methoxyestradiol; D000284:Administration, Oral; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D006801:Humans; D013058:Mass Spectrometry; D015394:Molecular Structure; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D004958:Estradiol; D000077584:2-Methoxyestradiol