ESTIMATION OF THE WITHDRAWAL PERIOD FOR AMOXICILLIN IN POMPANO (TRACHINOTUS BLOCHII) SERUM AND MUSCLE

Amoxicillin is one of the most popular antibiotics used in aquaculture. To ensure the residue of amoxicillin in the serum and the muscle of pompano (Trachinotus blochii) is below the established tolerance levels; we used reversed phase high-performance liquid chromatography (HPLC) to measure the amoxicillin in pompano after oral administration. The pharmacokinetics of amoxicillin in the serum and the muscle of pompano were established by single oral administration or administrations for five consecutive days at the dose of 40 mg/kg. After different depletion periods, amoxicillin residue was analyzed in both the serum and the muscle fillets by HPLC. The verified concentrations of this method were 0.01 to 10 μg/mL; the limit of detection (LOD) and the limit of quantitation (LOQ) were 0.04 and 0.1 μg/g. The concentration of amoxicillin in the serum of pompano reached the maximum threshold of 7.36 μg/g after 0.5 h depletion in the experiment with a single dose of amoxicillin (40 mg/kg of body weight). In addition, the maximal concentration (1.96 μg/g) of amoxicillin was detected in the muscle 2 h after depletion. Furthermore, the residue levels had decreased below the limit of detection after 48 h and 72 h in the serum and the muscle. Here we also suggested that 5 days of withdrawal were required after the multiple dosing of amoxicillin.