Pharmacokinetics and milk penetration of moxifloxacin after intramuscular administration to lactating goats

The pharmacokinetics of moxifloxacin was studied following intramuscular administration of 5 mg/kg to healthy lactating goats (n = 6). Moxifloxacin concentrations were determined by high performance liquid chromatography assay with fluorescence detection. The moxifloxacin plasma concentration versus time data could best be described by a one-compartment model. The plasma moxifloxacin clearance (Cl) was mean standard deviation (±SD) 0.49 ± 0.14 L/h kg. The apparent volume of distribution (Vz) was 0.83 ± 0.20 L/kg. The terminal half-life (t1/2λz) was 1.31 ± 0.64 h. Moxifloxacin penetration from blood to milk was rapid and the high AUCmilk/AUCplasma and Cmax-milk/Cmax-plasma ratios reached indicated a good penetration of moxifloxacin into the milk.