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Pharmacokinetics and Bioequivalance of Five Commercially Available Formulations of Omeprazole: A Preliminary Report
Author(s) -
Sykes B.W.,
Underwood C.,
Mills P.C.
Publication year - 2014
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12323_50
Subject(s) - bioequivalence , pharmacokinetics , omeprazole , bioavailability , plasma concentration , pharmacology , chemistry , chromatography , medicine
Reasons for performing study The pharmacokinetics and bioequivalence of different formulations of omeprazole have not been published. Objectives To compare the pharmacokinetics and bioavailability of 4 commercially available formulations of omeprazole to an existing reference formulation. Study design A single dose cross‐over bioequivalence study. Methods Six adult Thoroughbred horses were used. Two generic buffered formulations ( OG and AG ), one commercial enteric coated formulation ( GZ ) and one compounded enteric coated formulation ( BO ) were compared to the reference buffered formulation ( GG ). Each formulation was administered at a total dose of 2 g (equivalent to 4 mg/kg bwt for a 500 kg horse) in a cross‐over design. Blood samples were collected at 0, 15, 30, 45, 60, 75, 90, 105, 120, 150, 180, 210, 240, 300 and 360 min, the plasma was separated and frozen. Plasma omeprazole concentrations were determined by UPLC‐MS . Noncompartmental pharmacokinetic analyses were performed using PK Solver. Results The mean (± s.d.) area‐under‐the‐curve ( AUC 0‐t/0‐inf_obs ) (μg/ml*min), C max (μg) and T max (min) for each formulation was; OG – 59.4 ± 20.1, 0.37 ± 0.12, 87.5 ± 38.4; AG – 77.3 ± 53.7, 0.34 ± 0.24, 170.0 ± 62.0; GZ – 102.9 ± 51.1, 0.86 ± 0.68, 67.5 ± 29.6; BO – 88.0 ± 37.4, 0.59 ± 0.39, 95.0 ± 47.1; GG – 57.5 ± 35.3, 0.41 ± 0.22, 57.5 ± 19.9. Conclusions The results of this study suggest that differences are present between commercially available formulations of omeprazole. Caution should be exercised in extrapolating results of clinical studies from one formulation to another. Ethical animal research: This study was performed under an ethics permit issued by the NSW Department of Primary Industries and in accordance with relevant state laws and legislation. Explicit owner informed consent for participation in this study was not stated. Sources of funding: This study was funded by a grant from the G rayson‐ J ockey Club Research Foundation. Competing interests: The manufacturers of G astrozol ( GZ ), Abgard ( AG ) and BOVA ( BO ) have previously funded research by B . W . S ykes. None of the companies contributed to the present study.