Measurement of ketoprofen in horse urine using gas chromatography-mass spectrometry.

The research discusses a gas chromatography-mass spectrometry (GC-MS) method to detect the presence of an anti-inflammatory drug, ketoprofen, in horse urine. The method allows for ketoprofen detection up to 16 days after application.

Methodology

• The study used GC-MS to identify the presence of ketoprofen in horse urine. This method is used to separate and quantify complex mixtures.
• An extraction process using diethyl ether was used on 2 mL urine samples. The residues were then evaporated and injection into the GC-MS system.
• The research also used Selected Ion Monitoring (SIM) mode for the detection. The SIM mode makes it possible to detect low-abundance compounds in the presence of high-abundance compounds.

Validation and Results

• The technique was validated using flurbiprofen as the internal standard. The linearity studies showed a strong linear correlation, with a coefficient of 0.9998 for ketoprofen within the range of 10ng/mL to 10,000ng/mL.
• The recovery rate was at 95%, proving the method to be highly effective.
• The limit of quantitation (LOQ) was found to be 10 ng/mL, which is the smallest concentration of the drug that could be reliably measured.
• Applying this method to horse urine samples showed that ketoprofen can be detected for up to 16 days after a topical application of 1.1g of ketoprofen in a gel formulation.

Implications of the Study

• The method has potential practical implications, particularly in the regulation of horse racing, where the use of performance-enhancing substances needs to be closely monitored.
• Understanding the period during which a drug like ketoprofen can be detected in a horse’s system could be crucial for ensuring fair competition in horse racing.