• geese
• HPLC-UV
• ivermectin
• pharmakokinetics

Ivermectin (IVM) is a member of the avermectin class with a broad-spectrum of antiparasitic activity (arthropods and nematodes).
Since 1981 IVM was labelled as antiparasitic agent in cattle, sheep, and horses.
In poultry, IVM has shown to be effective against nematode infections, but pharmacokinetic studies in geese are not available in the literature.
The aim of this study was to assess the pharmacokinetic profile of IVM in geese.
Ten healthy male Bilgoraska geese underwent a two-phase parallel study design with a washout period of three months.
In the first phase the ten geese were IV administered with 0.2 mg/Kg IVM, while in the second phase they were PO treated with IVM at the same dosage. Blood samples were collected at selected time point up to 480 h after each administration.
The analytical drug quantification was performed using HPLC-UV (wavelength = 242 nm). The sample clean-up was performed using the protein precipitation technique. The analytical method was validated in blank goose plasma according to the EMA guidelines. It was characterized by an optimal linearity and a LOQ of 0.25 μg/mL. The pharmacokinetic analysis was carried out using a non-compartmental approach.
After the IV administration IVM was quantifiable up to 240 h while after PO treatment up to 144 h in the majority of geese. The AUC and t1/2kel values were statistically different between the two treatments. The oral bioavailability was low (19.6%).
In conclusion, IVM was characterized by a long persistence in the goose plasma. The PO administration may be not the optimal route of administration due to the low bioavailability.