Assay validation for vilanterol and its metabolites in human urine with application for doping control analysis.

Abstract

A bioanalytical method for detecting the ultra-long-acting beta2 -agonist (U-LABA) inhaled vilanterol and its metabolites, GSK932009 and GW630200, in urine was developed to potentially monitor permitted therapeutic versus prohibited supratherapeutic use in sport. The World Anti-Doping Agency (WADA) has established urinary concentration thresholds for the beta2 -agonists salbutamol and formoterol. Therapeutic use of vilanterol (25 μg once daily) was recently permitted by WADA; however, there is no established decision limit for adverse analytical findings due to insufficient urine concentration data. In this study, we validated an assay to detect vilanterol in urine collected from four healthy male and female athletes 0-72 h who received inhaled corticosteroid fluticasone furoate/U-LABA vilanterol (800/100 μg) combination, four times the normal therapeutic dose. After administration, subjects performed 1 h of bike ergometer exercise. The experiment was conducted again after repeat dosing for 1 week. Our method utilised liquid chromatography with tandem mass spectrometry and was validated over urine concentrations of 5-5000 (vilanterol) and 50-50,000 pg/ml (GSK932009 and GW630200). Plasma samples were analysed for vilanterol, using a previously validated assay. The peak concentration values for urine vilanterol, GSK932009 and GW630200 were 9.5, 10.4 and 0.17 ng/ml, for single dosing, and 18.6, 19.5 and 0.20 ng/ml, for repeat dosing. Urine samples from four volunteers using the final validated method are reported, demonstrating this assay has sensitivity to detect vilanterol or GSK932009 in urine for ≥72 h post single or repeat dosing with 800/100 μg fluticasone furoate/vilanterol, whereas GW630200 was quantifiable ≤4h post dose.