Detection of quinine and its metabolites in horse urine by gas chromatography-mass spectrometry.

This research article details a study in which the presence of quinine and its metabolites were successfully detected in horse urine by utilizing gas chromatography-mass spectrometry.

Study Design and Methodology

• Quinine sulfate was orally given to a thoroughbred mare and urine samples were collected over a period of 45.5 hours.
• These samples were then analysed using a method known as gas chromatography-mass spectrometry, employing both electron impact ionization and positive-ion chemical ionization mass spectrometry.

Findings and Results

• The analysis revealed the presence of quinine and five potential metabolites in the horse’s urine after the urine was enzyme-hydrolysed.
• All detected metabolites appeared to have undergone some form of oxidation.
• The parent compound, quinine, could be identified in the urine samples for about 16 hours post-administration.
• Some phase I biotransformation products were identifiable in urine even up to 40 hours after the drug was administered.

Implications and Conclusions

• The findings of this research underline the effectiveness of gas chromatography-mass spectrometry in detecting traces of quinine and its metabolites in horse urine.
• This method can therefore be used as a significant tool in drug and metabolite detection and possibly for anti-doping purposes in horse racing.
• The fact that some metabolites were identifiable even 40 hours after drug administration shows the long-standing, traceable impact of quinine once it is ingested.