The pharmacokinetics and tissue distribution of DWP20373, a novel fluoroquinolone, were examined in rats and beagle dogs after a single intravenous and oral administration. Analysis of DWP20373 in plasma, tissue, and urine was performed by both HPLC and microbiological assay. The plasma drug concentration declined biexponentially both rats and beagle dogs. In the rats, the terminal drug elimination half-life (t$_{1}$2$eta$/) was 64 min (IV) and 57 min (PO) by bioassay, and 76 min (IV) and 77 min (PO) by HPLC. Whereas in beagle dogs, t$_{1}$2$eta$/ was 196 min (IV) and 350 min (PO). The volume of distribution at steady-state (Vd$_{ss}$ ) was 811 ml/kg (bioassay) and 2061 ml/kg (HPLC) in rats, and 2738 ml/kg (bioassay) in beagle dogs. The total body clearance (Cl$_{t}$) of DWP20373 was 10 ml/min/kg (bioassay) and 7 ml/min/kg (HPLC) in rats, and 11 m1/min/kg (bioassay) in beagle dogs. The extent of bioavailability after oral administration was 49% (bioassay) and 67% (HPLC) in rats, and 84% (bioassay) in beagle dogs. The 24-h urinary recovery, measured by bioassay, was 2.7% after oral dosing and 5.5% after intravenous dosing in rats. Serum protein binding ratio determined at 27g/ml was 78%. This drug was also distributed in tissues in the decreasing order of liver, kidney, spleen, lung, heart, and muscle determined at 30 min after oral administration.on.