Pharmacokinetics of ketoprofen enantiomers following intravenous and oral administration to exercised Thoroughbred horses.

The research article describes a study conducted to understand how Thoroughbred horses process ketoprofen, a common pain and inflammation relief medication, after it is given intravenously and orally. The study also wanted to determine how readily the horse’s body absorbs this medication from the currently available injectable formulation and a paste formulation.

Study Details

• Two forms of ketoprofen or KTP (injectable and paste formulations) were administered to Thoroughbred horses in two different ways – through the vein (intravenously) and by mouth (orally).
• After administration, blood and urine samples from the horses were collected at different time intervals up to 96 hours to monitor the presence of KTP.
• The concentration of KTP enantiomers, which are mirror-image versions of the medication (R(-) KTP and S(+) KTP), were identified and measured using Liquid Chromatography–Mass Spectrometry/Mass Spectrometry (LC–MS/MS).
• Pharmacokinetic analyses, which is the study of how a drug is absorbed, distributed, metabolized, and eliminated from the body, were performed based on the obtained measurements.

Results

• The results for systemic clearance, which refers to the ability of the body to remove the drug from the bloodstream, show values of 0.345 ± 0.033 for R(-) KTP and 0.167 ± 0.016 for S(+) KTP in units of L/kg/h.
• The steady state volume of distribution, which essentially tells how well the drug is distributed throughout the body, is 0.344 ± 0.044 for R(-) KTP and 0.298 ± 0.025 for S(+) KTP in units of L/kg.
• The terminal elimination half-life, reflecting the time it takes for the concentration of the drug to reduce by half in the body, is 2.49 ± 0.077 hours for R(-) KTP and 2.86 ± 0.102 hours for S(+) KTP.
• The oral bioavailability, which indicates how much of the drug reaches the bloodstream when taken orally, varies for the two forms. For the injectable formulation, it is 69.5 ± 10.3% for R(-) KTP and 88.2 ± 15.9% for S(+) KTP, while for the paste form it is 53.0 ± 6.0% for the R(-) KTP and S(+) KTP.

In essence, the study provides valuable information about how horses’ bodies metabolize and eliminate ketoprofen when administered in different forms and consumed in different ways. These findings can help inform appropriate dosing strategies for this medication in horses.