This study investigated the residue of tulathromycin (TLM) on the lung tissue of pigs intramuscularly injected with 2.5 mg/kg body weight as a single dose. Nine healthy cross swine were intramuscularly injected with the drug. Three treated animals were arbitrarily selected to be sacrificed at 7, 10 and 14 days after treatment. TLM residue concentrations in lung tissue were determined using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The drug was extracted from lung samples using acetonitrile followed by clean-up with n-hexane. The analyte was separated on a Hypersil GOLDTM liquid chromatography column using 0.1% formic acid in deionized distilled water and acetonitrile. The correlation coefficient (R2) of the calibration curve was 0.9981, and the limits of detection and quantification were 10 and 50 μg/kg, respectively. Recoveries at three spiking levels ranged between 95.0-98.2%, and relative standard deviations were less than 3.95%. In TLM-treated group, the concentration of TLM on 7, 10 and 14 days post-treatment was 627.3, 496.9, 259.1 μg/kg, respectively. The developed method is sensitive and reliable for detection of TLM in porcine lung tissues. In addition, it can detect below the maximum residue limits in animal-derived food products destined for human consumption.

Abstract
서 론
재료 및 방법
    시약 및 재료
    표준원액 및 표준용액의 조제
    실험동물 및 시료채취
    시료 전처리
    기기분석조건
    분석법 검증
결 과
    TLM의 크로마토그램
    검량곡선, 검출한계 및 정량한계
    회수율과 정밀성
    돼지 폐 조직 중 TLM 잔류분석
고 찰
REFERENCES

• Jun-Ho Song(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University)
• Suk Kim(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University)
• Hu-Jang Lee(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University) Corresponding Author.