Pharmacokinetics of ceftiofur sodium in equine pregnancy

M. L. Macpherson, S. Giguère, M. A. Pozor, E. Runcan, T. W. Vickroy, S. A. Benson, M. H.T. Troedsson, J. N. Hatzel, J. Larson, E. vanden Berg, A. A. Kelleman, L. C. Sanchez, M. M. LeBlanc

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5 Scopus citations


Eleven pregnant pony mares (D270-326) were administered ceftiofur sodium intramuscularly at 2.2 mg/kg (n = 6) or 4.4 mg/kg (n = 5), once daily. Plasma was obtained prior to ceftiofur administration and at 0.5, 1, 2, 4, 8, 12, and 24 hr after administration. Eight pony mares were re-enrolled in the study at least 3 days from expected foaling to ensure steady-state concentrations of drug at the time of foaling. Mares were administered ceftiofur sodium (4.4 mg/kg, IM) daily until foaling. Parturition was induced using oxytocin 1 hr after ceftiofur sodium administration. Allantoic and amniotic fluid, plasma, and colostrum samples were collected at time of foaling. Serial foal plasma samples were obtained. Placental tissues were collected. Desfuroylceftiofur acetamide (DCA) concentrations were measured in samples by high-performance liquid chromatography (HPLC). Mean (±SD) peak serum concentrations of DCA were 3.97 ± 0.50 μg/ml (low dose) and 7.45 ± 1.05 μg/ml (high dose). Terminal half-life was significantly (p =.014) shorter after administration of the low dose (2.91 ± 0.59 hr) than after administration of the high dose (4.10 ± 0.72 hr). The mean serum concentration of DCA from mares at time of foaling was 7.96 ± 1.39 μg/ml. The mean DCA concentration in colostrum was 1.39 ± 0.70 μg/ml. DCA concentrations in allantoic fluid, amniotic fluid, placental tissues, and foal plasma were below the limit of quantification (<0.1 μg/ml) and below the minimum inhibitory concentration of ceftiofur against relevant pathogens. These results infer incomplete passage of DCA across fetal membranes after administration of ceftiofur sodium to normal pony mares.

Original languageEnglish
Pages (from-to)656-662
Number of pages7
JournalJournal of Veterinary Pharmacology and Therapeutics
Issue number6
StatePublished - Dec 2017

Bibliographical note

Funding Information:
This work was funded by the Grayson-Jockey Club Research Foundation and the University of Florida Equine Endowment. Drugs were provided by Zoetis/Pfizer Animal Health (ceftiofur sodium) and Merck Animal Health (altrenogest). The authors gratefully acknowledge the intellectual contributions of Dr. Michelle LeBlanc (now deceased) to the design of this study.

Publisher Copyright:
© 2017 John Wiley & Sons Ltd

ASJC Scopus subject areas

  • Pharmacology
  • Veterinary (all)


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