Analytical possibilities for the detection of stanozolol and its metabolites

In sports doping, as well in man as in horseracing, stanozolol (Stan) was abused and became the subject of metabolism research. Also in veterinary practice, stanozolol became an important misused anabolic steroid. Like most other anabolic steroids, stanozolol has poor gas chromatographic behavior. It is difficult to detect in urine, because of low urinary excretion and renal clearance. This is due to the rapid metabolization, leading to low concentration levels of the parent compound found in urine. Therefore, most research studies have focused on the detection of its urinary metabolites. For the identification of the metabolites, different methods of extraction and detection are described in the literature. These are reviewed in this article. Most authors use a hydrolysis to free the phase II metabolites. Extraction procedures vary from solid-phase extraction (SPE), liquid–liquid (L–L) extraction to immunoaffinity chromatography (IAC). For the final detection, the use of gas chromatography (GC)–mass spectrometry (MS) can be compared with liquid chromatography (LC)–MSn. Different metabolites are identified depending on the administration of stanozolol in the animal experiment (oral or intramuscular). Analyses for these analytes in other matrices are also briefly discussed.