Pharmacokinetics and tissue disposition of danofloxacin in sheep

The plasma pharmacokinetics of danofloxacin administered at 1.25 mg kg-1 body weight by the intravenous and intramuscular routes were determined in sheep. Tissue distribution was also determined following administration by the intramuscular route at 1.25 mg kg-1 body weight. Danofloxacin had a large volume of distribution at steady state (Vdss) of 2.76 +/- 0.16 h (mean +/- S.E.M.) L kg-1, an elimination half-life (t1/2 beta) of 3.35 +/- 0.23 h, and a body clearance (C1) of 0.63 +/- 0.04 L kg-1 h-1. Following intramuscular administration it achieved a maximum concentration (Cmax) of 0.32 +/- 0.02 microgram mL-1 at 1.23 +/- 0.34 h (tmax) and had a mean residence time (MRT) of 5.45 +/- 0.19 h. Danofloxacin had an absolute bioavailability (F) of 95.71 +/- 4.41% and a mean absorption time (MAT) of 0.81 +/- 0.20 h following intramuscular administration. Mean plasma concentrations of > 0.06 microgram mL-1 were maintained for more than 8 h following intravenous and intramuscular administration. Following intramuscular administration highest concentrations were measured in plasma (0.43 +/- 0.04 microgram mL-1), lung (1.51 +/- 0.18 micrograms g-1), and interdigital skin (0.64 +/- 0.18 microgram g-1) at 1 h, duodenal contents (0.81 +/- 0.40 microgram mL-1), lymph nodes (4.61 +/- 0.35 micrograms g-1), and brain (0.06 +/- 0.00 microgram mL-1) at 2 h, jejunal (10.50 +/- 4.31 micrograms mL-1) and ileal (5.25 +/- 1.67 micrograms mL-1) contents at 4 h, and colonic contents (8.94 +/- 0.65 micrograms mL-1) at 8 h.