The present study evaluated the pharmacokinetic profiles of danofloxacin (DNX) in freshwater crocodiles (Crocodylus siamensis), following single intramuscular (i.m.) administrations at two different dosages of 6 and 12 mg/kg body weight (b.w.). Blood samples were collected at assigned times up to 168 h. DNX in the harvested crocodile plasma was extracted using liquid-liquid extraction and analyzed using a validated high-performance liquid chromatography method equipped with fluorescence detection. The pharmacokinetic analysis was performed using a non-compartmental approach. DNX in plasma was quantifiable from 5 min to 168 h after i.m. administration at the two dosages in freshwater crocodiles. The area under the curve (AUC) and maximum concentration (Cmax ) values increased in a dose-dependent fashion. Long elimination half-life (48.18 and 67.29 h) and low clearance (0.024 and 0.020 ml/g h) were obtained in the high- and low-dose groups, respectively. According to the pharmacokinetic-pharmacodynamic surrogate (AUC0-24h /MIC > 125), i.m. single administration of DNX at a dosage of 6 mg/kg b.w. is predicted to have antibacterial success for disease caused by bacteria with MIC < 0.04 μg/ml in the freshwater crocodile, C. siamensis.
Keywords: danofloxacin; freshwater crocodiles; high-performance liquid chromatography; pharmacokinetics.
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