Mass spectrometric identification and characterization of a new long‐term metabolite of metandienone in human urine

Anabolic‐androgenic steroids are some of the most frequently detected drugs in amateur and professional sports. Doping control laboratories have developed numerous assays enabling the determination of administered drugs and/or their metabolic products that allow retrospectives with respect to pharmacokinetics and excretion profiles of steroids and their metabolites. A new metabolite generated from metandienone has been identified as 18‐nor‐17 β ‐hydroxymethyl,17 α ‐methyl‐androst‐1,4,13‐trien‐3‐one in excretion study urine samples providing a valuable tool for the long‐term detection of metandienone abuse by athletes in sports drug testing. The metabolite was characterized using gas chromatography/(tandem) mass spectrometry, liquid chromatography/tandem mass spectrometry and liquid chromatography/high‐resolution/high‐accuracy (tandem) mass spectrometry by characteristic fragmentation patterns representing the intact 3‐keto‐1,4‐diene structure in combination with typical product ions substantiating the proposed C/D‐ring structure of the steroid metabolite. In addition, structure confirmation was obtained by the analysis of excretion study urine specimens obtained after administration of 17‐CD 3 ‐labeled metandienone providing the deuterated analogue to the newly identified metabolite. 18‐Nor‐17 β ‐hydroxymethyl,17 α ‐methyl‐androst‐1,4,13‐trien‐3‐one was determined in metandienone administration study urine specimens up to 19 days after application of a single dose of 5 mg, hence providing an extended detection period compared with commonly employed strategies. Copyright © 2006 John Wiley & Sons, Ltd.