Pharmacokinetics of R(-) and S(+) carprofen after administration of racemic carprofen in donkeys and horses.

This research is an investigation of the pharmacokinetics of two forms of carprofen, R(-) and S(+), when given intravenously to both horses and donkeys. The results suggest that the dosage intervals typically used for horses may not be suitable for donkeys.

Study Methodology

• The study was conducted using five clinically normal donkeys and three clinically normal horses.
• A bolus dose of carprofen was intravenously administered to these animals and blood samples were collected at distinct intervals for 48 hours.
• The samples were studied through high-performance liquid chromatography to determine the concentrations of the carprofen enantiomers.
• A plasma concentration-time curve was plotted for each animal to estimate pharmacokinetic variables.

Findings and Conclusion

• Both in donkeys and horses, the area under the plasma concentration versus time curve (AUC) was found greater for the R(-) carprofen enantiomer than S(+) carprofen enantiomer.
• In case of the R(-) carprofen enantiomer, the AUC and mean residence time (MRT) were found to be significantly less and total body clearance (CIT) was significantly greater in horses compared to donkeys.
• For the S(+) carprofen enantiomer, AUC, MRT were significantly less and CIT and apparent volume of distribution at steady state were significantly greater in horses than in donkeys.
• These differences in pharmacokinetic properties of carprofen between horses and donkeys suggest that the dosing intervals used for horses may not be appropriate for donkeys.