Detection of stanozolol and its metabolites in equine urine by liquid chromatography–electrospray ionization ion trap mass spectrometry

Abstract

The equine phase I and phase II metabolism of the synthetic anabolic steroid stanozolol was investigated following its administration by intramuscular injection to a thoroughbred gelding. The major phase I biotransformations were hydroxylation at C16 and one other site, while phase II metabolism in the form of sulfate and beta-glucuronide conjugation was extensive. An analytical procedure was developed for the detection of stanozolol and its metabolites in equine urine using solid phase extraction, acid solvolysis of phase II conjugates and analysis by positive ion electrospray ionization ion trap LC-MS.

Direct detection of serum psilocin glucuronide by LC/MS and LC/MS/MS: time-courses of total and free (unconjugated) psilocin concentrations in serum specimens of a “magic mushroom” user

“…Liquid chromatography/mass spectrometry (LC/MS) and LC/MS/MS are powerful tools for directly detecting highly polar and nonvolatile conjugates; many research groups including our own have reported the detection of conjugates of various compounds using LC/MS and LC/ MS/MS [8][9][10][11][12][13][14][15][16][17][18][19][20]. We reported the identification of urinary psilocin glucuronide (PCG) by LC/MS and LC/MS/MS, and the optimization of its enzymatic hydrolysis conditions for urine, and showed that all PC excreted into urine was in the form of its glucuronide conjugate [15]; in the present study, this line of experiments has been extended to PCG and PC in human serum.…”

Urine Fingerprints of Stanozolol Treated Horses by Liquid Chromatography High Resolution Mass Spectrometry

“…16β-hydroxystanozolol was established as a major equine urinary metabolite of stanozolol following administration by intramuscular injection. Also, two other metabolites with additional hydroxylation were tentatively proposed by McKinney et al [6] as 16α-hydroxystanozolol and a 15α or -hydroxystanozolol ( Figure 1). …”

“…Stanozolol, commonly sold under the name Winstrol (oral) and Winstrol Depot (intramuscular) and often called Winny was commercially developed by Winthrop Laboratories (Sterling Drug) in 1962, and has been approved for human use. Figure 1: Structural formula of stanozolol and its known or proposed metabolic hydroxylation sites [6].…”

Simultaneous Doping Analysis of Main Urinary Metabolites of Anabolic Steroids in Horse by Ion-trap Gas Chromatography–Tandem Mass Spectrometry

“…On the other hand, McKinney et al reported that the main urinary metabolite of STZ in horse is the 16-hydroxylated product of STZ. 9 We synthesized reference standards of 16a-hydroxyfurazabol, 16a-hydroxystanozolol, and 16b-hydroxystanozolol, and identified each metabolite in our laboratory, but did not publish the results. As results, the main metabolites of FRZ and STZ were 16a-hydroxyfurazabol (HFR) and 16a-hydroxystanozolol (HST), respectively.…”