Single and multiple oral amoxicillin treatment in geese: a pharmacokinetic evaluation

1. Although amoxicillin has broad-spectrum antibiotic activity and is extensively used in poultry, its use has never been investigated in geese. This study aimed to evaluate the pharmacokinetics of amoxicillin after a single and multiple oral doses in geese.2. A total of 20 geese were enrolled in this study and randomly pooled in two groups (n = 10). In group I, animals were treated with a single oral 20 mg/kg dose of amoxicillin, while geese in group II were administered multiple doses (20 mg/kg/day for 4 d). Concentrations of amoxicillin in plasma were analysed using a validated HPLC-UV method and drug plasma concentrations were modelled for each subject using a non-compartmental approach.3. amoxicillin showed rapid absorption after a single-dose treatment, with an elimination half-life of approximately 1 h. C_max, T_max and AUC values differed statistically between groups I and II (after the first dose administered). A large variability was observed in the pharmacokinetic profiles and drug accumulation may occur after the multiple administration.4. No accumulation in plasma was predicted from an in-silico simulation performed using the same multiple dosage schedule. The in-silico simulation does not seem to accurately predict in-field conditions.