Pharmacokinetics of single-dose oral ponazuril in weanling goats

Ponazuril (toltrazuril sulfone) is a triazine antiprotozoal agent that targets apicomplexan organisms. Ponazuril may have clinical application in the treatment of clinical coccidiosis due to Eimeria species in goats, along with other protozoal infections. To evaluate the absorption, distribution and elimination characteristics of ponazuril in goats, a sensitive, validated high-pressure liquid chromatography and mass spectroscopy method for ponazuril in caprine plasma was developed. After a single oral dose of ponazuril at 10mg/kg, plasma samples from seven weanling goats were collected and assayed. Plasma concentrations of ponazuril in the goats peaked at 36 +/- 13h post drug administration at a concentration of 9 +/- 2g/mL. Concentrations declined to an average of 4.2 +/- 0.8g/mL after 168h with an average elimination half-life of 129 +/- 72h post drug administration. Thisstudy shows that ponazuril is relatively well absorbed after a single oral dose in goats. Efficacy trials are underway to determine clinical efficacy ofponazuril in the treatment of clinical coccidiosis in goats at 10mg/kg dosage.