Detection and identification of flunixin after multiple intravenous and intramuscular doses to horses.

The research explores different methods to test for the use of flunixin, an anti-inflammatory drug, in horses and compares the detection times using these methods. The findings reveal varying levels of effectiveness and detection durations between the different testing methods.

Objective of the Study

• The study aimed at comparing different techniques used to detect the presence of Flunixin, a non-steroidal anti-inflammatory drug, in horses treated with this drug.
• The motives extended to recording the detection periods—how long after administration the drug could be detected—using the various methods.
• The drug was administered daily in recommended doses via both intramuscular (IM) and intravenous (IV) methods.

About Flunixin and its Administration

• Flunixin is a non-steroidal anti-inflammatory drug that is officially approved for use in horses.
• For this study, the drug was administered to eight mares at 1.1 mg per kilogram of their body weight over five consecutive days.
• The dosages were delivered via both intravenous (IV) and intramuscular (IM) methods.

Detection Methods and Findings

• Flunixin presence in the test samples was detected using four methods – enzyme-linked immunosorbent assay (ELISA), thin layer chromatography (TLC), high-performance liquid chromatography (HPLC), and gas chromatographic-mass spectrometric (GC-MS) methods.
• Urine samples of the horses were collected at different intervals from the drug administration to be tested using these methods.
• The detection time – the period in which Flunixin was detected – varied for each method.
• The quickest detection times were between 24 to 48 hours, found when using the TLC method.
• Longer detection periods of up to 15 days were observed with HPLC, GC-MS, and Flunixin ELISA methods.

Implications of the Findings

• The results show that certain methods could result in long detection times that may flag a positive test for Flunixin use in racehorses even when the drug would not be having any clinical effects.
• This is because Flunixin typically only produces clinical effects lasting 24-36 hours in horses, meaning even if the drug was detected after this period, it would not be impacting the animal’s racing performance.