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The Influence of Age on the Pharmacokinetics of Enrofloxacin and Ciprofloxacin in Calves
by
, , , , and
Orhan Corum
1
,
Murat Yuksel
2,
Duygu Durna Corum
1,
Elisa Escudero
3
,
Pedro Marín
3
,
Mario Giorgi
4, 
Halis Oguz
5,
Erdinc Turk
1,
Devran Coskun
6,
Elena Badillo
3,
María Teresa Yuste
3 and
Kamil Uney
5,* 1
Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Hatay Mustafa Kemal, Hatay 31060, Türkiye
2
Department of Obstetrics and Gyneacology, Faculty of Veterinary Medicine, University of Hatay Mustafa Kemal, Hatay 31060, Türkiye
3
Department of Pharmacology, Faculty of Veterinary Medicine, University of Murcia, 30100 Murcia, Spain
4
Department of Veterinary Sciences, University of Pisa, San Piero a Grado, 56121 Pisa, Italy
5
Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Selcuk, Konya 42031, Türkiye
6
Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Siirt, Siirt 56100, Türkiye
*
Author to whom correspondence should be addressed.
Vet. Sci. 2026, 13(6), 538; https://doi.org/10.3390/vetsci13060538 (registering DOI)
Submission received: 11 April 2026
/
Revised: 18 May 2026
/
Accepted: 21 May 2026
/
Published: 29 May 2026
Simple Summary
This study examined the pharmacokinetic behavior of enrofloxacin and its active metabolite, ciprofloxacin, in calves at various developmental stages. Three age groups (one, four, and eight months old) were evaluated to assess how age influences drug disposition. This research focused on comparing key pharmacokinetic parameters such as distribution volume, clearance, half-life, and the metabolic conversion ratios to determine age-related differences. The results highlighted significant variations in drug pharmacokinetics among different age groups, with younger calves showing a higher metabolic conversion ratio and distinct pharmacokinetic profiles. These findings emphasize the value of considering age when determining appropriate dosing regimens for enrofloxacin in calves. This study provides valuable insights into how growth and maturation affect enrofloxacin pharmacokinetics, which can inform more effective and safer therapeutic strategies in veterinary practice.
Abstract
This study investigated age-related variations in the pharmacokinetics of enrofloxacin and its active metabolite, ciprofloxacin, in calves. This study was carried out on a total of 18 calves using a parallel pharmacokinetic design. Eighteen animals were assigned to three age groups, one, four, and eight months old, and received a single intravenous dose of 10 mg/kg enrofloxacin. Serial blood samples collected over 48 h were analyzed using high-performance liquid chromatography to determine plasma concentrations. In one-month-old calves, the pharmacokinetic parameters revealed a volume of distribution at steady state (Vdss) of 1.44 L/kg, total clearance (ClT) of 0.42 L/h/kg, elimination half-life (t1/2ʎz) of 2.52 h, and area under the concentration versus time curve (AUC0-last) of 23.36 h*μg/mL. Notably, the AUC0-last of enrofloxacin was increased and ClT decreased in the older age groups (four and eight months). Additionally, the Vdss of enrofloxacin significantly decreased in eight-month-old calves relative to younger groups, while t1/2ʎz showed statistically significant differences in the order of four months > eight months > one month. The conversion ratio of enrofloxacin to ciprofloxacin was highest in one-month-old calves (43.39%) and diminished in four-month-old (25.73%) and eight-month-old (23.04%) calves. The results indicated that the pharmacokinetics of enrofloxacin and ciprofloxacin at a dose of 10 mg/kg in cattle exhibited significant variation with age. However, pharmacokinetic/pharmacodynamic investigations in cattle of different ages are required to assess the impact of these pharmacokinetic alterations on clinical efficacy.
Keywords:
age; cattle; ciprofloxacin; enrofloxacin; intravenous; pharmacokinetics
