Pharmacokinetics of intravenous, plain oral and enteric-coated oral omeprazole in the horse

• Published in: Journal of veterinary pharmacology and therapeutics 2015-04, Vol.38 (2), p.130-136
• Main Authors: Sykes, B. W., Underwood, C., McGowan, C. M., Mills, P. C.
• Format: Article
• Language: English
• Subjects: Administration, Oral; Animals; Anti-Ulcer Agents - administration & dosage; Anti-Ulcer Agents - pharmacokinetics; Area Under Curve; Cross-Over Studies; Female; Half-Life; Horses - blood; Horses - metabolism; Injections, Intravenous; Male; Omeprazole - administration & dosage; Omeprazole - pharmacokinetics
• ISSN: 0140-7783; 1365-2885
• DOI: 10.1111/jvp.12169

The objectives were to document the pharmacokinetics of intravenous, enteric‐coated oral and plain oral omeprazole in fasted horses and to investigate the impact of feeding on the bioavailability of an enteric‐coated omeprazole. Twelve horses received four treatments: intravenous omeprazole (0.5 mg/kg) in the fasted state (IV‐Fasted), enteric‐coated omeprazole (4 mg/kg) orally in the fasted state (ECO‐Fasted), enteric‐coated omeprazole (4 mg/kg) orally in the fed state (ECO‐Fed) and plain omeprazole (4 mg/kg) orally in the fasted state (PL‐Fasted). Plasma omeprazole concentrations were determined by UHPLC‐MS. Bioavailability was higher (P = 0.038) in the ECO‐Fasted group (21.5 [9.0–27.7]%) than the PL‐Fasted group (10.1 [7.7–13.3]%). Similarly, AUC0‐∞ was higher in the ECO‐Fasted group than the PL‐Fasted group (P = 0.027). No significant differences were present between the ECO‐Fasted and ECO‐Fed groups with regards to bioavailability, Cmax, Tmax or AUC0‐∞. When the half‐life data from the oral formulations was pooled, it was longer than that observed in the IV‐Fasted group (100 [73–118] min) and 35 [34‐39] min, respectively; P