Development of a gas chromatographic-mass spectrometric method using multiple analytes for the confirmatory analysis of anabolic steroids in horse urine. I. Detection of testosterone phenylpropionate administrations to equine male castrates.

The research article discusses a method using gas chromatography-mass spectrometry (GC-MS) to detect the use of testosterone-based pro-drugs in gelded horses by analyzing their urine.

Understanding the Methodology

The method proposed in the study involves several steps:

• The extraction of steroid conjugates from horse urine using C18-bonded cartridges. C18-bonded cartridges contain a commonly-used type of silica gel, coated with C18 hydrocarbon chains, which are very effective at retaining nonpolar and moderately polar compounds during the extraction process.
• The fractionation of these steroid conjugates into glucuronic acid and sulpho-conjugates is done using Sephadex LH-20 column chromatography. This is a type of size-exclusion chromatography which separates molecules based on their size.
• Following the deconjugation, or separation, neutral steroids are partially purified using thin-layer chromatography (TLC). TLC is a technique used to separate non-volatile mixtures.
• Finally, after derivatization – the process of chemically modifying a compound to produce a derivative with improved analytical properties – the steroids are analyzed by capillary GC-MS in either the selected-ion or full-scan mode. Specific analytes (test substances) are then detected and confirmed as signs of pro-drug use.

Findings of the Study

Out of the three analytes tested:

• The analyte 5 alpha-androstane-3 beta, 17 alpha-diol could be detected in the glucuronic acid fraction for about ten days.
• The analytes 5 alpha-androstane-3 beta,17 beta-diol and testosterone could be detected in the sulpho-conjugate fraction up to nineteen days after administration of a single therapeutic dose (50 mg) of testosterone phenylpropionate. This was tested on cross-bred and thoroughbred castrated male horses.

Implications and Future Work

The researchers noted that the development of this method has a high potential for the detection of neutral metabolites of other veterinary anabolic steroids in horse urine. The reasons for development of this method, its validation and its potential applications are also explored. This research is an essential contribution to safeguarding the integrity of veterinary and equine sports practices. The study also presents opportunities for future work on improving the detection methods of anabolic steroids in animal urine.