Effect of castration procedure on the pharmacokinetics of meloxicam in goat kids

The aim of this study was to determine the changes in the pharmacokinetics of meloxicam in goat kids who were castrated following the administration of xylazine. Six goat kids were used for the study. The study was performed in two periods according to a longitudinal study, with a 15-day washout period between periods. In the first period (Control group), 1 mg/kg meloxicam was administered by i.v. route to kids. In the second period (Castration group), the kids were sedated with 0.3 mg/kg xylazine and castration was performed following meloxicam administration. Plasma meloxicam concentration was analyzed using HPLC-UV, and pharmacokinetic parameters were calculated by noncompartmental model. In the control group following the administration of meloxicam, mean elimination half-life (t_1/2ʎz), area under the concentration–time curve (AUC_0−∞), total body clearance (Cl_T), and volume of distribution at steady-state (V_dss) were 13.50 ± 0.62 hr, 41.10 ± 2.86 hr µg/ml, 24.43 ± 1.75 ml hr⁻¹ kg⁻¹, and 0.45 ± 0.03 L/kg, respectively. In the castration group, the t_1/2ʎz of meloxicam prolonged, AUC_0−∞ increased, and Cl_T and V_dss decreased. In conclusion, the excretion of meloxicam from the body slowed and the t_1/2ʎz was prolonged in the castrated goat kids following xylazine administration. However, there is a need to determine the pharmacodynamics of meloxicam in castrated goat kids.