Doxycycline pharmacokinetics in geese.

Area of Science:

• Veterinary Pharmacology
• Avian Medicine
• Drug Metabolism

Background:

• Doxycycline is a widely used antibiotic in veterinary medicine.
• Understanding its pharmacokinetics in geese is crucial for effective treatment protocols.
• Limited data exists on doxycycline pharmacokinetics and efficacy in avian species.

Purpose of the Study:

• To characterize the pharmacokinetics of doxycycline following single intravenous and oral doses in geese.
• To simulate multiple-dose regimens and predict plasma concentrations.
• To evaluate the potential therapeutic efficacy of doxycycline against avian Mycoplasma infections.

Main Methods:

• A two-phase crossover study involving ten geese with a two-week washout period.
• Single intravenous and oral administration of doxycycline (20 mg/kg).
• Blood sample collection up to 48 hours post-administration, analyzed via HPLC-UV.
• Non-compartmental pharmacokinetic analysis and multiple-dose simulations.

Main Results:

• Doxycycline exhibited a long elimination half-life (13 hours) in geese.
• Moderate oral bioavailability (43%) was observed, with significant differences in AUC between routes.
• The pharmacokinetic/pharmacodynamic index (%T>MIC) of 71% suggests efficacy against certain Mycoplasma species.
• Multiple-dose simulations indicated low drug accumulation with a 10 mg/kg/day regimen.

Conclusions:

• Doxycycline demonstrates moderate oral absorption and a prolonged elimination in geese.
• A 10 mg/kg/day dosage for 5 days appears sufficient for therapeutic efficacy against Mycoplasma without causing excessive plasma concentrations.
• These findings support the use of doxycycline for treating specific infections in geese.