An accurate and precise method for the determination of tulathromycin in swine plasma was developed and validated.Plasma samples were analyzed by high-performance liquid chromatography with tandem mass spectrometry de...An accurate and precise method for the determination of tulathromycin in swine plasma was developed and validated.Plasma samples were analyzed by high-performance liquid chromatography with tandem mass spectrometry detection （HPLC-MS/MS） using electrospray ionization （ESI）.Tulathromycin was extracted from plasma by precipitation with acetonitrile and separated using a Phenomenex Luna 5 μm C18 column （150 mm×2.0 mm） at a flow rate of 0.25 mL min^-1.Solvent A consisted of 0.002 mol L^-1 ammonium acetate and formic acid （999：1,v/v）,and solvent B was acetonitrile.The mass spectrometer was operated in the selected-ion mode with atmospheric pressure chemical ionization to monitor the respective MH＋ ions,namely,m/z 577.3 for tulathromycin and m/z 679.3 for the internal standard roxithromycin.The calibration curves were linear in a dynamic range of 2.0-500 ng mL^-1 on the column.The accuracy was ranged from 95.25 to 109.75%,and the precision was ranged from 2.81 to 7.72%.The recoveries measured at 3 concentration levels （20,250,and 500 ng mL^-1） were higher than 98%.The method described above is efficient,and has the required accuracy and precision for rapid determination of tulathromycin in plasma.The method was applied to study the pharmacokinetics of tulathromycin in swine,and tulathromycin demonstrated a rapid absorption,wide distribution,and slow elimination after intramuscular administration.展开更多
The postantibiotic effect （PAE） is defined as the suppression of bacterial growth persisting after a short exposure of bacterial cultures to an antibiotic. This phenomenon has obvious clinical interest, because anti...The postantibiotic effect （PAE） is defined as the suppression of bacterial growth persisting after a short exposure of bacterial cultures to an antibiotic. This phenomenon has obvious clinical interest, because antibiotic agents which produce extensive PAEs could be administrated less frequently without reducing efficacy. The minimum inhibitory concentration （MIC） and PAE of tulathromycin and erythromycin on five isolates of Actinobacillus pleuropneumonia were determined. All strains were susceptible to tulathromycin （ MIC： 0.25 - 1.00 μg/ml） and resistant to erythromycin （MIC： 32 -128 μg/ml）. The mean PAEs of 1 xMIC, 2 xMIC, 4 xMIC and 8 xMIC of tulathromycin against the tested isolates were 0.62, 1.53, 2.70 and 4.50, respectively. These results indicated that tulathromycin might be administered at longer time intervals than those already applied. This is in tavorite of the clinical rational use of antimicrobial druqs.展开更多
建立了高效液相色谱-串联质谱法测定土拉霉素在猪肝脏、肾脏、肌肉、皮脂和肺脏中的残留检测方法，并初步探讨了土拉霉素的基质效应。样品用乙腈提取，涡旋振荡离心后经正己烷脱脂，C18固相萃取柱净化后，40℃氮气吹干，用50％乙腈定容...建立了高效液相色谱-串联质谱法测定土拉霉素在猪肝脏、肾脏、肌肉、皮脂和肺脏中的残留检测方法，并初步探讨了土拉霉素的基质效应。样品用乙腈提取，涡旋振荡离心后经正己烷脱脂，C18固相萃取柱净化后，40℃氮气吹干，用50％乙腈定容。以Penomenex Luna C18柱为色谱柱，乙腈-2mmol／L乙酸铵水溶液（含0．1％甲酸）为流动相，梯度洗脱；流速0．25mL／min；柱温35℃。质谱条件为电喷雾离子源，检测方式为正离子多离子反应监测（MRM），外标法定量。在10．0～500μg／kg范围内，方法的线性关系良好（r〉0．99）。5种基质中土拉霉素的检出限为3～5μg/kg，定量下限均为10μg/kg。在高、中、低3个加标水平下的平均回收率为74％～96％，批内相对标准偏差（RSD）为4．0％～16％，批间RSD为7．0％-15％。该法准确、灵敏，适用于猪组织中土拉霉素的测定。展开更多
基金supported by the Guangzhou Technology Pillar Program for the Development of New Broad-Spectrum Antibiotic Tulathromycin and Industrialization during 2010,China(2010Z1-E371)the International Communication and Cooperation for the Development of New Veterinary Medicine of Tulathromycin Raw Materials and Its Preparation,China(2010DFA32610)
文摘An accurate and precise method for the determination of tulathromycin in swine plasma was developed and validated.Plasma samples were analyzed by high-performance liquid chromatography with tandem mass spectrometry detection （HPLC-MS/MS） using electrospray ionization （ESI）.Tulathromycin was extracted from plasma by precipitation with acetonitrile and separated using a Phenomenex Luna 5 μm C18 column （150 mm×2.0 mm） at a flow rate of 0.25 mL min^-1.Solvent A consisted of 0.002 mol L^-1 ammonium acetate and formic acid （999：1,v/v）,and solvent B was acetonitrile.The mass spectrometer was operated in the selected-ion mode with atmospheric pressure chemical ionization to monitor the respective MH＋ ions,namely,m/z 577.3 for tulathromycin and m/z 679.3 for the internal standard roxithromycin.The calibration curves were linear in a dynamic range of 2.0-500 ng mL^-1 on the column.The accuracy was ranged from 95.25 to 109.75%,and the precision was ranged from 2.81 to 7.72%.The recoveries measured at 3 concentration levels （20,250,and 500 ng mL^-1） were higher than 98%.The method described above is efficient,and has the required accuracy and precision for rapid determination of tulathromycin in plasma.The method was applied to study the pharmacokinetics of tulathromycin in swine,and tulathromycin demonstrated a rapid absorption,wide distribution,and slow elimination after intramuscular administration.
基金supported by grants from the National Natural Science Foundation of China (30700604)
文摘The postantibiotic effect （PAE） is defined as the suppression of bacterial growth persisting after a short exposure of bacterial cultures to an antibiotic. This phenomenon has obvious clinical interest, because antibiotic agents which produce extensive PAEs could be administrated less frequently without reducing efficacy. The minimum inhibitory concentration （MIC） and PAE of tulathromycin and erythromycin on five isolates of Actinobacillus pleuropneumonia were determined. All strains were susceptible to tulathromycin （ MIC： 0.25 - 1.00 μg/ml） and resistant to erythromycin （MIC： 32 -128 μg/ml）. The mean PAEs of 1 xMIC, 2 xMIC, 4 xMIC and 8 xMIC of tulathromycin against the tested isolates were 0.62, 1.53, 2.70 and 4.50, respectively. These results indicated that tulathromycin might be administered at longer time intervals than those already applied. This is in tavorite of the clinical rational use of antimicrobial druqs.
文摘建立了高效液相色谱-串联质谱法测定土拉霉素在猪肝脏、肾脏、肌肉、皮脂和肺脏中的残留检测方法，并初步探讨了土拉霉素的基质效应。样品用乙腈提取，涡旋振荡离心后经正己烷脱脂，C18固相萃取柱净化后，40℃氮气吹干，用50％乙腈定容。以Penomenex Luna C18柱为色谱柱，乙腈-2mmol／L乙酸铵水溶液（含0．1％甲酸）为流动相，梯度洗脱；流速0．25mL／min；柱温35℃。质谱条件为电喷雾离子源，检测方式为正离子多离子反应监测（MRM），外标法定量。在10．0～500μg／kg范围内，方法的线性关系良好（r〉0．99）。5种基质中土拉霉素的检出限为3～5μg/kg，定量下限均为10μg/kg。在高、中、低3个加标水平下的平均回收率为74％～96％，批内相对标准偏差（RSD）为4．0％～16％，批间RSD为7．0％-15％。该法准确、灵敏，适用于猪组织中土拉霉素的测定。
