Pharmacokinetics and bioavailability of oral firocoxib in adult, mixed-breed goats

Amy K. Stuart, Butch KuKanich, Luciano S. Caixeta, Johann F. Coetzee, Emily A. Barrell

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6 Scopus citations


Pharmacokinetic (PK) studies of oral firocoxib in large animal species have been limited to horses, preruminating calves, and adult camels. The aim of this study was to describe pharmacokinetics and bioavailability of firocoxib in adult goats. Ten healthy adult goats were administered 0.5 mg/kg firocoxib intravenously (i.v.) and per os (p.o.) in a randomized, crossover study. Plasma firocoxib concentrations were measured over a 96-hr period for each treatment using HPLC and mass spectrometry, and PK analysis was performed. The p.o. formulation reached mean peak plasma concentration of 139 ng/ml (range: 87–196 ng/ml) in 0.77 hr (0.25–2.00 hr), and half-life was 21.51 hr (10.21–48.32 hr). Mean bioavailability was 71% (51%–82%), indicative of adequate gastrointestinal absorption of firocoxib. There were no negative effects observed in any animal, and all blood work values remained within or very near reference range at the study's conclusion. Results indicate that oral firocoxib is well-absorbed and rapidly reaches peak plasma concentrations, although the concentration also decreased quickly prior to the terminal phase. The prolonged half-life may suggest tissue accumulation and higher plasma concentrations over time, depending on dosing schedule. Further studies to determine tissue residue depletion, pharmacodynamics, and therapeutic concentrations of firocoxib in goats are necessary.

Original languageEnglish (US)
Pages (from-to)640-646
Number of pages7
JournalJournal of Veterinary Pharmacology and Therapeutics
Issue number6
StatePublished - Nov 1 2019

Bibliographical note

Funding Information:
We thank Dr. Jeremiah Easley for providing the animals used in this study, Dr. Christine Russell for her contributions to data acquisition, and Dr. Hyun Joo for conducting the analysis of plasma samples for firocoxib. The pharmacokinetic software (Phoenix? 8.0) license was provided by Certara USA, Inc. as a part of the company's Academic Centers of Excellence program. Funding was provided by the Colorado State University College of Veterinary Medicine and Biomedical Science.

Publisher Copyright:
© 2019 John Wiley & Sons Ltd


  • bioavailability
  • firocoxib
  • goat
  • pharmacokinetics


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