Distribution of marbofloxacin in the bronchoalveolar region in healthy calves

The purpose of this study was to clarify the distribution of marbofloxacin (MBFX) within the bronchoalveolar region of calves. Four clinically healthy calves were intramuscularly injected with a single dose of MBFX (2 mg/kg). Samples of plasma and bronchoalveolar lavage fluid (BALF) were obtained for each calf at 0 (before administration), 1, 2, 6 and 24 hr after injection of MBFX. The injections and series of sample collections were conducted and repeated again after two weeks. The results show that the MBFX concentrations in the pulmonary epithelial lining fluid (ELF) were significantly higher than that in plasma and in alveolar cells at 2 hr after injection (P<0.05). For concentrations of MBFX within the ELF, the mean area under the MBFX concentration curve calculated during the 0 to 24 hr timeframe (AUC(0–24)) was significantly higher than the mean determined from samples collected from the plasma (P<0.05). These results suggest that intramuscularly injected MBFX was well distributed in the bronchoalveolar region.