牛奶中利福昔明残留消除规律研究

Study on the Depletion of Rifaximin Residue in Milk

关键词:  牛奶  利福昔明  超高效液相色谱-串联质谱  残留消除

Key words:  milk  Rifaximin  UPLC-MS/MS  residue depletion

摘要:

为研究新型奶牛干乳期乳房注入剂利福昔明在牛奶中的残留消除规律,在常规饲养条件下,选择处于干乳期的12头健康奶牛分为2组(每组6头),在预产期前60天,按推荐剂量(100mg)及2倍推荐剂量(200mg)两种剂量通过乳房注入方式给药,在产犊泌乳后的12、24、36、48、60和72h共6个时间点采集奶样,用超高效液相色谱-串联质谱法检测。液相条件：色谱柱为BEH C18(50?2.1mm,1.7μm),0.1%甲酸乙腈和0.1%甲酸水为流动相进行梯度洗脱。质谱条件：ESI＋离子源,MRM方式采集。结果表明：推荐剂量组12h时6头奶牛有2头检出利福昔明,残留量分别为2.84和4.50μg/kg；24h时已全部检不出药物。2倍推荐剂量组12h时6头奶牛均检出利福昔明,残留量仅在1.56~10.2μg/kg之间,24h时有2头检出,残留量分别为1.41和1.28μg/kg,36h时全部检不出药物。两组检出的残留量均远低于欧盟规定的牛奶中最高残留限量60μg/kg。因此,实验用12头干乳期奶牛使用利福昔明乳房注入剂后在产犊泌乳时牛奶中的休药期均为零。

Abstract:

In order to study the depletion of Rifaximin residue in milk. 12 healthy dairy cattles in dry period were divided into two groups, and administered Rifaximin by breast infusion method at recommended dosage (100mg) and twice recommended dosage(200mg) at 60 days before expected date of birth, respectively.12 dairy cattles were milked at 12, 24, 36, 48, 60, 72h after the lactation The residue of Rifaximin in milk was determined by ultra high performance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS). LC condition: the chromatography column is BEH C18 column of 50×2.1mm,1.7μm；mobile phase is acetonitrile(0.1?) and water (0.1?). Mass Spectrometry condition: ESI and MRM mode The detective results indicated that Rifaximin residues were 2.84 and 4.50ug/kg in 2 cattles at 12h in the recommended dosage groups; Rifaximin residues were 1.56~10.2μg/kg in 6 cattles at 12h, 1.41 and 1.28μg/kg in 2 cattles at 24h in twice recommended dosage groups. All detected residues were less than MRL (60μg/kg). Therefore, 12 dairy cattles have 0 withdraw time after Rifaximin was administered.