Analysis of phenylbutazone residues in horse tissues with and without enzyme-hydrolysis by LC-MS/MS.

This research examines the effect of adding an additional enzyme-hydrolysis step in the detection of Phenylbutazone residues in horse tissues, with findings showing a significant increase in recovery of the residues.

Objective

The scientists conducted this study to understand how the process of enzyme hydrolysis impacts the detection of Phenylbutazone (PBZ) and its metabolite, oxyphenbutazone (OXPBZ), in horse tissues. PBZ is a drug used to manage pain and inflammation in racing horses, but not approved for horses meant for human consumption. The research aimed to provide insights into how different methods can affect test results for the drug’s residue.

Method

• A female horse was given Phenylbutazone at a dosage of 8.8mg/kg for three days, and sacrificed six days following the last administration.
• Tissues from the liver, kidney, and muscles were collected for testing.
• The tissues were extracted, then cleaned using a silica-based solid-phase extraction (SPE). The SPE process was preceded by a weak-anion exchange SPE method.
• Finally, the samples were analyzed using an in-house validated Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) method for PBZ and OXPBZ.

Results and Conclusion

The results showed that incorporating an enzymatic hydrolysis step significantly improved the recovery of both PBZ and OXPBZ residues. Therefore, including this step in the testing process allows for more accurate detection of PBZ residue in horse tissues. The study did not provide details on the implications of these findings or recommendations for future studies or applications. It also didn’t mention if there are specific contexts or conditions where this method would be particularly advantageous.