Quantitative determination of stanozolol and its metabolite in urine by gas chromatography/mass spectrometry.

The amount of stanozolol and 3'-hydroxystanozolol in urine was determined after oral administration of stanozolol. A gas chromatograph/mass selective detector equipped with a capillary column was used for these determinations. The GC/MS was operated in the SIM mode, and m/z 581, 669, and 315 were monitored for stanozolol, 3'-hydroxystanozolol, and calusterone (internal standard), respectively. The detection limit was approximately 1 ng/mL for both steroids. The maximum excretion rate of stanozolol was reached in 8 h and the maximum of 3'-hydroxystanozolol in 19 h. However, only 3% of the administered amount was recovered in urine.