Comparative pharmacokinetic dispositions of omeprazole and its metabolites following intravenous and oral administration in sheep and goats

Abstract

This study aimed to determine the pharmacokinetic behavior of omeprazole (OMP) and its metabolites in sheep and goats following both intravenous (IV) and oral (PO) administration. Twelve one-year-old female animals, comprising six Awassi sheep and six Alpine goats, were used to compare pharmacokinetic parameters after a single dose of OMP (1.0 mg/kg IV and 4.0 mg/kg PO). Plasma levels of OMP, hydroxyomeprazole (OMP‑OH), omeprazole sulfone (OMP‑Sulfone), and omeprazole sulfide (OMP‑Sulfide) were measured at specified time points. Results revealed that the pharmacokinetic profiles of OMP in sheep differed significantly from those in goats for both IV and PO routes. After IV administration, sheep showed greater systemic exposure (AUC0‑∞: 1.84 ± 0.38 µg·h/mL) and a longer elimination half-life (T1/2λz: 0.26 ± 0.05 h) compared to goats (AUC0‑∞: 0.67 ± 0.16 µg·h/mL; T1/2λz: 0.14 ± 0.03 h). Conversely, following PO administration, OMP bioavailability was low in both species, with sheep displaying an AUC0‑∞ of 0.81 ± 0.38 µg·h/mL (F %: 11.00) and goats 0.33 ± 0.21 µg·h/mL (F %: 12.31). Metabolites OMP‑OH and OMP‑Sulfone were not detected in plasma after PO dosing in either species. However, after IV dosing, metabolite levels were higher in sheep than in goats. Consequently, these findings may support the development of more rational therapeutic strategies for the use of OMP in small ruminant medicine.