Bioavailabilty of amoxicillin from oral and intramuscular administered to flounder, Paralichthys olivaceus

Amoxicillin (AMX) is a ß-lactamic derivative largely used in veterinary medicine for its broad spectrum, high in vitro activity against Gram-positive and Gram-negative bacteria, and efficacy on the microorganisms which have developed resistance to the old drugs in use in aquaculture. The oral treatment dosage of AMOX approved for the treatment of Pasteurellosis and furunculosis in yellowtail is 20~40 mg/kg fish/day for 7 days treatment in Korea. The comparative pharmacokinetics of AMOX after single oral (40, 80 mg/kg/day), intramuscular (30, 60 mg/kg/day), and intravenous (1 mg/kg/day) administration in cultured olive flounder, Paralichthys olivaceus were examined. The kinetic profile of absorption, distribution and elimination of AMOX in plasma were calculated to a one- or two-compartment model using the nonlinear least-squares program WinNonlin 5.01 (Pharsight Co. USA). The following parameters were calculated after the treatments: AUC (the area under the concentration-time curve), Tmax (time for maximum concentration), Cmax (maximum concentration) and Et (elimination time), etc.