Pharmacokinetics of Carprofen Administered Intravenously at Different Doses in Goats

This investigation focuses on understanding the pharmacokinetic behavior of intravenously administered carprofen at doses of 0.7, 1.4, and 4 mg/kg in goats. Eighteen animals were randomly assigned into three groups, with six goats per group, and blood samples were collected at 22 time points post-administration. Plasma concentrations were analyzed using a validated HPLC-UV method, and key pharmacokinetic parameters were derived using non-compartmental analysis. Results show that, at 0.7 mg/kg, carprofen exhibited the total clearance (ClT) of 2.19 mL/h/kg, volume of distribution at steady state (Vdss) of 126.56 mL/kg, area under the curve (AUC0-last) of 321.00 h*µg/mL, and elimination half-life (t1/2ʎz) of 44.32 h. When comparing doses, an increase in ClT was observed at 4 mg/kg, and the volume of distribution increased at both 1.4 and 4 mg/kg dosages. Additionally, a reduction in dose-normalized AUC0-last was evident at the highest dose. Data showed that the effect of the drug may be prolonged as the dose increases. These differences between dose groups may be clinically insignificant after the single administration of all doses. Carprofen can be used at all three dose levels in goats; however, vigilance regarding the potential side effects and drug residues is essential, especially during repeated treatments.