Pharmacokinetic Behaviour of Enrofloxacin after Single Intramuscular Dosage in American Black Vultures (<i>Coragyps atratus</i>)

• Main Authors: Samanta Waxman, José Julio de Lucas, Guillermo Wiemeyer, Laura Torres Bianchini, Manuel Ignacio San Andrés, Casilda Rodríguez
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Antibiotics
• Subjects: black vultures; enrofloxacin; pharmacokinetic; PK/PD; Monte Carlo simulation
• Online Access: https://www.mdpi.com/2079-6382/10/8/957

The aim of the study was to investigate the intramuscular pharmacokinetics of enrofloxacin in black vultures (<i>Coragyps atratus</i>). The pharmacokinetics of a single intramuscular dose (10 mg/kg) of enrofloxacin was studied in six vultures. Plasma concentrations of enrofloxacin and its active metabolite, ciprofloxacin, were determined by high-performance liquid chromatography (HPLCuv). Pharmacokinetic parameters were estimated using non-compartmental and compartmental analysis. After intramuscular administration, enrofloxacin showed a rapid and complete absorption, reaching a Cmax value of 3.26 ± 0.23 μg/mL at 1.75 ± 0.53 h. A long terminal half-life of 19.58 h has been observed. Using previously published MIC values to perform a PK/PD analysis, cumulative fraction responses obtained after Monte Carlo simulation for AUC/MIC > 30, 50 and 125 were 72.93%, 72.34% and 30.86% for <i>E. coli</i> and 89.29%, 88.89% and 58.57% for <i>Mycoplasma synoviae</i>, respectively. Cumulative fraction responses obtained for Cmax/MIC index were 33.93% and 40.18% for <i>E. coli</i> and <i>M. synoviae</i>, respectively. The intramuscular administration of 10 mg/kg could be appropriate to treat infectious diseases caused by gram-positive bacteria with MIC value lower than 1 µg/mL; however, although enrofloxacin showed a slow elimination in black vultures, plasma concentrations were insufficient to reach the gram-negative stablished breakpoints.