Pharmacokinetic profiles of florfenicol in spotted halibut, Verasper variegatus, at two water temperatures.

The pharmacokinetic profiles of florfenicol in the spotted halibut (Verasper variegatus) were investigated at 15 and 20°C water temperatures, respectively. Florfenicol content in plasma samples was analyzed using an HPLC method. Drug concentration versus time data were best fitted to a three-compartment model after a single intravenous administration (15 mg/kg BW), and fitted to a two-compartment model after an oral administration (30 mg/kg BW) at 15 and 20°C. The florfenicol concentration in the blood increased slowly during the 12 hr following an oral administration at 15°C, with a peak concentration (C ) of 9.1 mg/L, and then declined gradually. The half-lives of absorption, distribution, and elimination phase were 2.18, 5.66 and 14.25 hr, respectively. The bioavailability (F) was calculated to be 24.14%. After an oral administration at 20°C, shorter half-lives of absorption (1.33 hr), distribution (2.51 hr) and elimination (9.71 hr), a higher C (12.2 mg/L), and a similar F (23.98%) were found. Based on the pharmacokinetics and pharmacodynamics, an oral dose of 30 mg/kg BW was suggested to be efficacious for bacterial disease control in spotted halibut farming.