Tissue distribution of marbofloxacin in pigs after a single intramuscular injection

Tissue distribution of marbofloxacin was studied in pigs after a single intramuscular injection at 2.5 mg/kg body weight. Samples of plasma, muscle, liver, kidney, heart, lung, and muscle at the injection site were randomly collected from five pigs at 2, 6, 10, 24, 48, 72, and 96 h after administration. Marbofloxacin concentrations were determined by using high-performance liquid chromatography with ultraviolet detection and were subjected to non-compartmental analysis to obtain kinetic parameters. The elimination half-life (t_1/2λz) of marbofloxacin at the injection site was 22.12 h, while those in kidney, plasma, liver, lung, heart, and muscle were 16.75, 21.48, 21.84, 24.00, 24.45, and 28.91 h, respectively. Areas under the concentration-time curve from 0 h to ∞ (AUC_0-∞s) were calculated to be 31.17 hㆍμgㆍmL^-1 for plasma and 32.97, 33.92, 34.78, 37.58, 42.02, and 98.80 hㆍμgㆍg^-1 for heart, muscle, lung, liver, kidney, and injection site, respectively. The peak concentration (C_max) of marbofloxacin was 1.62 μg/mL in plasma and 1.71, 1.74, 1.86, 1.93, 2.45, and 7.64 μg/g in heart, lung, muscle, kidney, liver, and injection site, respectively. The results show that marbofloxacin was fast absorbed, extensively distributed, and slowly eliminated from pigs after a single intramuscular administration.