Pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin after intracoelomic administration in tortoises (Testudo hermanni)

Enrofloxacin belongs to the fluoroquinolone class of antibiotics. It is commonly used in a variety of reptile species due to its wide spectrum of efficacy, partly due to its formation of an active metabolite ciprofloxacin. Enrofloxacin shows wide disposition variability among all species resulting in large differences in the plasma concentrations of both enrofloxacin and ciprofloxacin. The aim of this study was to evaluate the pharmacokinetics of enrofloxacin and ciprofloxacin after a single intracoelomic injection of 10 mg/kg of enrofloxacin in 9 tortoises (Testudo hermanni). Blood samples were collected at 0, 0.5, 2, 4, 10, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240 and 264 h and analyzed using a validated high performance liquid chromatography (HPLC) florescence method. Plasma concentrations of enrofloxacin were quantifiable in all subjects for up to 240 h, while ciprofloxacin was detected in all subjects up to 120 h. The Cmax (s) of enrofloxacin and ciprofloxacin were 8614 ± 1116 ηg/mL obtained at 2.19 h and 605 ± 43 ηg/mL obtained at 4.23 h, respectively. The values of Cmax/MIC ratio and AUC0-24/MIC ratio of enrofloxacin with a MIC value of 0.5 µg/mL were 17.23 and 132.78, respectively. In conclusion, an administration of 10 mg/kg of enrofloxacin via the intracoelomic route in Hermann’s tortoises produced optimal pharmacodynamic parameters