Postmortem tissue samples: an alternative to urine and blood for drug analysis in racehorses.

The research study discusses the use of postmortem tissue samples for drug analysis in racehorses, when traditional urine or blood samples are not available, such as after sudden death. The study found that these tissue samples are equally effective for identifying drugs such as butorphanol, pentobarbital, and ergotamine.

Methodology

The research primarily focused on utilizing an alternative method for equine drug analysis. The process mainly relied on the use of equine postmortem tissue samples. The samples collected were frozen at -80 degrees Celsius until they were ready for analysis. About 30-40 gram portions of each organ were subjected to the following procedures:

• They were homogenized in a 0.1 M phosphate buffer (pH 7.4), which means they were broken down into even molecules using a particular buffer solution, so the sample became identical throughout.
• Deproteinization was carried out, a process where proteins are removed from the sample to prevent interference with subsequent testing procedures.
• The samples were then hydrolyzed with beta-glucuronidase, an enzyme that breaks down glucuronides, compounds commonly found in drugs and their metabolites.
• After preparing the sample, they were extracted and screened by thin-layer chromatography and immunoassay, both effective methods for identifying the presence of drugs or their metabolites.

Results and Analysis

Following the above process, samples that tested positive for any drugs were extracted again using high-flow, solid-phase extraction cartridges. After extraction, these samples were analyzed using gas chromatography-mass spectrometry, a method that separates components in a sample and identifies them based on their mass and charge. The results confirmed:

• The presence of butorphanol in two horses, known as HB355 and CD387.
• The presence of pentobarbital in horse HO940.
• The presence of ergotamine in horses HO940 and CD387.

Conclusion

Based on the findings of the study, the researchers concluded that postmortem tissue samples are just as effective as blood and urine samples in conducting forensic toxicology investigations when a racehorse suddenly dies. This provides a useful method when the conventional urine or blood samples are not obtainable, ensuring drug analysis can be performed, and necessary investigations can take place.