Enrofloxacin and amikacin pharmacokinetics in Scimitar-horned oryx (Oryx dammah) following a single intravenous dose

Abstract

Single dose pharmacokinetics of amikacin and enrofloxacin in adult Scimitar-horned oryx (Oryx dammah) were determined. The (mean) intravenous doses were 5.8mg/kg for amikacin and 1.3mg/kg for enrofloxacin, derived from metabolic energy scaling. For amikacin, the drug concentration versus time curve was best fit to a two-compartment model with maximum serum concentration after distribution of 30.5+4.7[]g/ml and mean elimination half-life of 97.0+31.8min. For enrof loxacin, the curve was best fit to one-compartment model with maximum serum concentration after distribution of 1.887+0.632btg/ml and mean elimination half-life of 41.2+27.5min. Model-independent parameters for amikacin were AUC, 5478+2828Ag/min/ml, volume of distribution, 0.152+0.02L/kg, clearance, 1.2+0.4ml/min/kg, and MRT, 136.5+49.Omin. Mean serum amikacin concentrations reached recommended peak concentrations (25[]g/ml) and below the recommended trough concentration (2[]g/ml) by 8hr. The serum amikacin concentrations were above selected bacterial MIC for up to 6hr. This amikacin dose administered parenterally to Scimitar-horned oryx at 12hr intervals should produce therapeutic serum concentrations for susceptible bacteria. For enrofloxacin, model-independent parameters were AUC, 173.63+147.5Ag/min/ml, volume of distribution, 0.80+0.30L/kg, clearance, 12.07+7.12ml/min/kg, and MRT, 77.22+72.8min. Mean serum enrofloxacin concentrations reached the recommended MIC (1.OAg/ml) which is bactericidal against most sensitive bacteria and remained above the MIC of other sensitive bacteria (0.5iAg/ml) consistently for 90min. The minimum enrofloxacin dose would be administered parenterally to Scimitar-horned oryx at 1.6mg/kg every 6-8hr for serum concentrations against susceptible bacteria. The dose appeared to have underestimated the oryx drug requirements.