Doping Control Analysis of Methylsulfonylmethane in Horses.

This study details the process and findings of an investigation into the use of methylsulfonylmethane (MSM), a natural sulphur compound, in horses and its regulation in horse racing. The research aimed to determine the rate at which MSM is eliminated from a horse’s system, allowing for accurate detection and regulation in the sport.

Research Context and Aim

• The study is set in the context of horse racing regulation, particularly the controls on substances with anti-inflammatory and analgesic effects such as MSM and DMSO (dimethyl sulfoxide). These compounds occur naturally but have established international residue limits (IRL) due to their potential for misuse.
• While there has been prior research on the elimination of DMSO in horses, there was no prior report on the elimination of MSM. This study sought to fill that gap.

Research Method

• In the study, two geldings were given Pure MSM twice daily for six days. After administration, urine and blood samples from these horses were collected and analysed.
• The analysis involved gas chromatography-mass spectrometry, a method used for identifying and quantifying substances. The blood samples additionally required protein precipitation before analysis.

Key Findings

• The researchers documented the elimination profiles of MSM in the horses’ urine and blood. They found that the maximum detection time in urine was approximately 4.5 days after the last MSM dose.
• They also found that plasma MSM in both horses was around 120 µg/mL 4.4 days after the last administered dose. This finding suggested a potential for 120 µg/mL as an IRL for regulating MSM in horse blood.
• The study’s analysis revealed that DMSO is not a significant metabolite of MSM in horses, an important finding for understanding the substance’s potential impacts and usage.

Significance of the Study

• This study contributes valuable knowledge for horse racing regulators, providing insight into how long MSM remains detectable in a horse’s system. This information is vital for determining appropriate testing schedules and monitoring techniques.
• The findings also advance our understanding of MSM usage in horses, which can support efforts to ensure fair competition in horse racing and protect the welfare of the animals.