The purpose of this study was to evaluate the pharmacokinetics (PK) of intravenously (IV) and subcutaneously (SC) administered nalbuphine in domestic goats. Nalbuphine hydrochloride was administered at 0.8 mg/kg for both IV and SC routes in six goats with a minimum of 10-day washout period between sample collection phases. Eighteen plasma samples were collected over a 36-hour period, analyzed using reverse phase high-performance liquid chromatography (HPLC). Plasma data were analyzed using compartmental and noncompartmental approaches. Following IV nalbuphine administration, elimination half-life, area under the plasma concentration time curve from time 0 to infinity (AUC0 - ∞), concentration at time zero (C0), and total body clearance were 120.4 ± 39.1 (min-1 ± SD), 17311.01 ± 7227.32 (min·ng·mL-1 ± SD), 675.6 ± 337.13 (ng·mL-1 ± SD), and 44.5 ± 13.8 (mL·min-1·kg-1 ± SD), respectively. After SC nalbuphine administration, elimination half-life, area under the plasma concentration time curve from time 0 to infinity (AUC0 - ∞), and maximum plasma drug concentration were 129 ± 52.9 (min-1 ± SD), 20826.5 ± 14376.2 (min·ng·mL-1), and 368.03 ± 503.78 (ng·mL-1). Calculated bioavailability for the SC route was 138 ± 126 (% ± SD). Nalbuphine in goats is characterized by rapid elimination and high subcutaneous bioavailability and may be a safe analgesic opioid option in goats in the future.
Keywords: Nalbuphine; analgesia; goat; opioid; pain management; pharmacokinetics.
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