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Pharmacokinetics and bioequivalence testing of five commercial formulations of omeprazole in the horse
Author(s) -
Sykes B. W.,
Underwood C.,
Greer R.,
McGowan C. M.,
Mills P. C.
Publication year - 2016
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/jvp.12240
Subject(s) - bioequivalence , omeprazole , pharmacokinetics , cmax , horse , pharmacology , chromatography , chemistry , medicine , biology , paleontology
Omeprazole is widely used in the treatment of equine gastric ulcer syndrome. To date, little is known about the relative pharmacokinetics of the different formulations making comparisons between products difficult. The objectives of the study were to investigate the relative pharmacokinetics of five commercially available formulations of omeprazole in the horse and to test for bioequivalence of four of the formulations using one of the formulations as a reference standard. Twelve mature T horoughbred horses were fasted for 16 h then administered 2 g of each formulation in a cross‐over design. Serial blood samples were collected and plasma omeprazole concentration was determined by ultra high‐performance liquid chromatography–mass spectrometry (UHPLC‐MS). No significant differences were present between three of the formulations and the reference formulation, while the fourth formulation had a lower C max and longer T max than the reference formulation. Bioequivalence against the reference formulation could not be demonstrated for any of the formulations tested. The findings of the study suggested that the method of protection utilised by different formulations of omeprazole (enteric‐coated granules vs. buffering) does not significantly alter the pharmacokinetics of the drug. Further work to establish bioequivalence is needed before direct comparisons can be drawn between different formulations.