Quantitative detection of salmeterol after inhalation in equine urine by liquid chromatography/tandem mass spectrometry.
A sensitive, accurate and precise liquid chromatography/tandem mass spectrometry (LC/MS(2)) method was developed for the quantification of salmeterol in the urine of horses. The method consists of a liquid-liquid extraction with tert-butylmethyl ether and isopropanol at pH 12 after enzymatic hydrolysis. The extracts are analysed using an LC/MS system equipped with an electrospray ionisation (ESI) probe. Method validation showed excellent linearity, specificity, accuracy, precision and intra-laboratory repeatability and reproducibility. The limit of quantitative detection was 0.25 ng/mL and the limit of detection was 0.125 ng/mL. The excretion profile was determined after administration of 500 microg salmeterol (Serevent) to four standard-bred mares via a metered dose inhaler (MDI) with an Equinehaler adapter. Salmeterol was detected from 1 h until 12 h post-administration. Maximum urinary concentrations varied between 2.3 and 14.9 ng/mL.
Doping Control Unit, Faculty of Vetrinary Medicine, University of Ghent, Salisburylaan 133, B-9820 Merelbeke, Belgium.
P
P
Van Eenoo
K
K
Deventer
F T
FT
Delbeke
D000280:Administration, Inhalation; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000652:urine*; D000420:Albuterol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000652:urine*; D000818:Animals; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D002976:Clenbuterol / Q000008:administration & dosage / Q000652:urine; D006736:Horses / Q000378:metabolism*; D007202:Indicators and Reagents; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D000068299:Salmeterol Xinafoate; D021241:Spectrometry, Mass, Electrospray Ionization
D000318:Adrenergic beta-Agonists; D007202:Indicators and Reagents; D000068299:Salmeterol Xinafoate; D000420:Albuterol; D002976:Clenbuterol