Tissue distribution of enrofloxacin after intramammary or simulated systemic administration in isolated perfused sheep udders.

Objective—To determine the tissue distribution of enrofloxacin after intramammary or simulated systemic administration in isolated perfused sheep udders by measuring its concentration at various sample collection sites. Sample—26 udders (obtained following euthanasia) from 26 healthy lactating sheep. Procedures—For each isolated udder, 1 mammary gland was perfused with warmed, gassed Tyrode solution. Enrofloxacin (1 g of enrofloxacin/5 g of ointment) was administered into the perfused gland via the intramammary route or systemically via the perfusion fluid (equivalent to a dose of 5 mg/kg). Samples of the perfusate were obtained every 30 minutes for 180 minutes; glandular tissue samples were obtained at 2, 4, 6, and 8 cm from the teat base after 180 minutes. The enrofloxacin content of the perfusate and tissue samples was analyzed via high-performance liquid chromatography with UV detection. Results—After intramammary administration, maximun perfusate enrofloxacin concentration was detected at 180 minutes...