Pharmacokinetics of R(-) and S(+) carprofen after administration of racemic carprofen in donkeys and horses.
OBJECTIVE
To compare plasma disposition of the R(-) and S(+) enantiomers of carprofen after IV administration of a bolus dose to donkeys and horses.


METHODS
5 clinically normal donkeys and 3 clinically normal horses.


METHODS
Blood samples were collected from all animals at time 0 (before) and at 10, 15, 20, 30, and 45 minutes and 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10, 24, 28, 32, and 48 hours after IV administration of a bolus of carprofen (0.7 mg/kg). Plasma was analyzed in triplicate via high-performance liquid chromatography to determine the concentrations of the carprofen enantiomers. A plasma concentrationtime curve for each donkey and horse was analyzed separately to estimate noncompartmental pharmacokinetic variables.


RESULTS
In donkeys and horses, the area under the plasma concentration versus time curve (AUC) was greater for the R(-) carprofen enantiomer than it was for the S(+) carprofen enantiomer. For the R(-) carprofen enantiomer, the AUC and mean residence time (MRT) were significantly less and total body clearance (CIT) was significantly greater in horses, compared with donkeys. For the S(+) carprofen enantiomer, AUC and MRT were significantly less and CIT and apparent volume of distribution at steady state were significantly greater in horses, compared with donkeys.


CONCLUSIONS
Results have suggested that the dosing intervals for carprofen that are used in horses may not be appropriate for use in donkeys.
Mealey
Katrina L
KL
Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA 99164, USA.
Matthews
Nora S
NS
Peck
Kenneth E
KE
Burchfield
Melissa L
ML
Bennett
Brad S
BS
Taylor
Tex S
TS
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002227:Carbazoles / Q000097:blood / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D018397:Equidae / Q000097:blood*; D006736:Horses / Q000097:blood*; D007536:Isomerism; D013997:Time Factors
D000894:Anti-Inflammatory Agents, Non-Steroidal; D002227:Carbazoles; C007005:carprofen