title: Measurement of tamsulosin in human serum by liquid chromatography-tandem mass spectrometry.
abstract: A simple, sensitive and robust method to extract tamsulosin from human serum, and quantify by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated and is applicable as a measure of compliance in clinical research. Tamsulosin was extracted from human serum (100μL) via liquid-liquid extraction with methyl tert-butyl ether (2mL) following dilution with 0.1M ammonium hydroxide (100μL), achieving 99.9% analyte recovery. Internal standard, d9-finasteride, was synthesised in-house. Analyte and internal standard were separated on an Ascentis(®) Express C18 (100mm×3mm, 2.7μm) column using a gradient elution with mobile phases methanol and 2mM aqueous ammonium acetate (5:95, v/v). Total run-time was 6min. Tamsulosin was quantified using a triple quadrupole mass spectrometer operated in multi-reaction-monitoring (MRM) mode using positive electrospray ionisation. Mass transitions monitored for quantitation were: tamsulosin m/z 409→228 and d9-finasteride m/z 382→318, with the structural formulae of ions confirmed by Fourier transform ion cyclotron resonance mass spectrometry (within 10ppm). The limit of quantitation was 0.2ng/mL, and the method was validated in the linear range 0.2-50ng/mL with acceptable inter- and intra-assay precision and accuracy and stability suitable for routine laboratory practice. The method was successfully applied to samples taken from research volunteers in a clinical study of benign prostatic hyperplasia.
authors.affiliation: Endocrinology, University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, 47, Little France Crescent, Edinburgh EH16 4TJ, United Kingdom. rupreti@staffmail.ed.ac.uk
authors.forename: Rita
authors.initials: R
authors.lastname: Upreti
authors.forename: Natalie Z M
authors.initials: NZ
authors.lastname: Homer
authors.forename: Gregorio
authors.initials: G
authors.lastname: Naredo
authors.forename: Diego F
authors.initials: DF
authors.lastname: Cobice
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Hughes
authors.forename: Laurence H
authors.initials: LH
authors.lastname: Stewart
authors.forename: Brian R
authors.initials: BR
authors.lastname: Walker
authors.forename: Ruth
authors.initials: R
authors.lastname: Andrew
mesh_terms: D000293:Adolescent; D000328:Adult; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D006801:Humans; D016014:Linear Models; D059625:Liquid-Liquid Extraction; D008297:Male; D008875:Middle Aged; D011470:Prostatic Hyperplasia; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013449:Sulfonamides / Q000097:blood* / Q000737:chemistry; D000077409:Tamsulosin; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D013449:Sulfonamides; D000077409:Tamsulosin