Detection of bazedoxifene, a selective estrogen receptor modulator, in human urine by LC-MS/MS / Masato Okano, Mitsuhiko Sato, Shinji Kageyama
- Drug Testing and Analysis (18 January 2022)
- PMID: 35043573
- DOI: 10.1002/dta.3225
Abstract
Bazedoxifene, a selective estrogen receptor modulator, has been explicitly included in the prohibited list issued by the World Anti-Doping Agency (WADA) since January 2020. A high-resolution liquid chromatography-tandem mass spectrometric detection method was developed to identify bazedoxifene and its metabolites in human urine and to quantify bazedoxifene (free plus glucuronide) for doping control purposes. Bazedoxifene acetate (20 mg) was orally administered to seven male volunteers, and the urine samples collected were analyzed using the developed method. The linearity ranged from 0.5 to 200 ng/mL, and the limit of detection was <0.2 ng/mL. The inter-day precision (2.2% to 3.6%) and the inter-day accuracy (-10.0% to 1.9%) were adequate. Bazedoxifene, bazedoxifene-N-oxide, and bazedoxifene gluco-conjugates were identified in the urine samples. The profiles of the urinary excretion indicated the presence of small amounts of free bazedoxifene and bazedoxifene-N-oxide, while bazedoxifene glucuronide was the predominant metabolite. The cumulative excretion amount of bazedoxifene (free form plus glucuronide conjugate) within 78 h after the administration was 0.7% to 1.3% of the total dose. In all subjects, bazedoxifene (free plus glucuronide) could be detected in urine up to 78 h after administration.
