Metabolism of boldenone in man: Gas chromatographic/mass spectrometric identification of urinary excreted metabolites and determination of excretion rates

Urinary metabolites of boldenone (androsta‐1,4‐dien‐17β‐ol‐3‐one) following oral administration of boldenone (doses from 11 to 80 mg) to man were isolated from urine via XAD‐2 adsorption and enzymatic hydrolysis with β‐glucuronidase from Escherichia coli. The isolated metabolites were derivatized with N‐methyl‐N‐trimethylsilyltrifluoroacetamide/trimethyliodosilane and analysed by gas chromatography/mass spectrometry with electron impact (EI) ionization at 70 eV. Boldenone (I) and four metabolites were identified after hydrolysis of the urine with β‐glucuronidase: 5β‐androst‐1‐en‐17β‐ol‐3‐one (II), 5β‐androst‐1‐ene‐3α,17β‐diol (III), 5β‐androst‐1‐en‐3α‐ol‐17‐one (IV) and 5β‐androst‐1‐en‐6β‐ol‐3,17‐dione (V). Five further metabolites in low concentration were identified without enzymatic hydrolysis after treatment of the urine with potassium carbonate: 5β‐androst‐1‐ene‐3,17‐dione (VI), 5β‐androst‐1‐ene‐3,17‐dione (VII), androsta‐1,4‐diene‐3,17‐dione (VIII), androsta‐1,4‐diene‐6β,17β‐diol‐3‐one (IX) and androsta‐1,4‐dien‐6β‐ol‐3,17‐dione (X). The identification of the metabolites is based on the gas chromatography retention index, high‐performance liquid chromatography retention index, high‐performance liquid chromatography retention, EI mps8 spectrum, chemical reactions of the isolated metabolites, and syotbeais of metabolites 11, In, IV, VI and VII. The EI mass spectra of the bis‐trimethylsiyl derivatives of boldenone and its metabolites display all intense molecular ions, M ‐ 15 ions and fragment ions originating from cleavage of the Bring. The excreted metabolites can be separated in basii extractable labile conjugates and in stable conjugates More than 95% of metabolites are excreted as stable conjugates.