Antimicrobial Activity of Florfenicol Against Fish Pathogenic Bacteria and Pharmacokinetics in Blood of Cultured Olive Flounder by Oral Administration

Florfenicol(FF)을 넙치(평균체중 $700{\pm}50$ g, $23{\pm}1.5^{\circ}C$ )에 1일 1회 경구(20 mg/kg BW) 투여한 다음, 경시적(1시간~168시간)으로 혈청 내 FF의 잔류량을 HPLC로써 분석하였다. FF의 경구 투여에 따른 넙치 체내 약물 혈중농도 측정결과를 바탕으로 two-compartment model로 WinNonlin program을 이용하여 FF의 흡수, 배설, 반감기 등 약물동태학적 매개변수(parameter)를 조사하였다. 혈청중 농도-시간곡선하 면적(AUC)은 22.51 ${\mu}g{\cdot}h/mL$ , 혈중최고농도( $C_{max}$ )는 0.84 ${\mu}L/mL$ , 혈중최고농도에 도달하는 시간( $T_{max}$ )은 8.62 시간, 약물이 혈중에서 완전히 0이 되는 시점인 예상소실시간(Et)은 447 계산되었다. 본 연구에서 얻어진 결과는 넙치에 FF를 처방하여 치료 계획을 수립할 때 유용하게 활용될 것으로 여겨진다. The pharmacokinetics of florfenicol (FF) after oral administration was studied in the cultured olive flounder, Paralichthys olivaceus, using high performance liquid chromatography (HPLC). After single administration of FF (20 mg/kg body weight) by oral route in olive flounder ( $700{\pm}50$ g, $23{\pm}1.5^{\circ}C$ ), the concentration in the serum was determined at 1, 5, 10, 15, 24, 30, 50 and 168 h post-dose. The kinetic profile of absorption, distribution and elimination of FF in serum were analyzed fitting to a two-compartment model by WinNonlin program. The area under the concentration-time curve (AUC), maximum concentration ( $C_{max}$ ), time for maximum concentration ( $T_{max}$ ) and elimination time were 22.51 ${\mu}g{\cdot}h/mL$ , 0.84 ${\mu}g/mL$ , 8.62 h and 447 h, respectively. The results of this study related to dosage and withdrawal times could be used for prescription of FF in field for the treatment of bacterial diseases in olive flounder.