The purpose of this study was to investigate the residue elimination of ceftiofur hydrochloride in milk of postpartum cows after intramammary infusing at dry-off. An ultra-high performance liquid chromatography-tandem...The purpose of this study was to investigate the residue elimination of ceftiofur hydrochloride in milk of postpartum cows after intramammary infusing at dry-off. An ultra-high performance liquid chromatography-tandem mass spectrometry （UPLC-MS/ MS） method was developed and validated to detect ceftiofur hydrochloride residue in milk. Through preprocessing, ceftiofur hydrochloride was derivatized into a more stable compound dedfuroyl ceftiofur acetamide （DCA） for further analysis. The linear range of DCA was 0.1 to 50 μg kg-1. Average recoveries of DCA were 82.52-105.86％. The intra-day and interday coefficients of variation （CV） were 2.95-9.82 and 6.41-7.43％, respectively. The limit of detection （LOD） and limit of quantitation （LOQ） scores were 0.05 and 0.1 μg kg-1, respectively. These parameters showed this method was reliable and valid. Twelve cows were administrated 10 mL ceftiofur hydrochloride by intramammary infusion （corresponding to 500 mg ceftiofur） to each udder after the last milking before the dry-off period. Milk was collected from each udder of cow at 12, 24, 36, 48, 60 and 72 h after calving and was mixed for each time point and each cow, then subjected to UPLC-MS/MS analysis. The results showed, the DCA concentrations in all milk samples were less than LOQ and the maximum residue limit （MRL） 100 μg kg-1, which suggested the withdrawal time of ceftiofur hydrochloride intramammary infusion used for preventing and curing mastitis in dry cows was 0 day. The study provided guidance for the clinical applications of ceftiofur hydrochloride intramammary infusion （dry cow）.展开更多
Gelatin ceftiofur alkali microsphere was prepared to observe its characteristics and evaluate preservation conditions. The glutaraldehyde was increased and the carboxylic methyl chitosan was added to improve the micro...Gelatin ceftiofur alkali microsphere was prepared to observe its characteristics and evaluate preservation conditions. The glutaraldehyde was increased and the carboxylic methyl chitosan was added to improve the microsphere. The experimental results show microspheres have a better morphology surface and fairly regular structure with 4% glutaraldehyde. The average particle size is 15.84 gm and particle size distribution is narrow which shows a good uniformity. Microsphere size was affected by the stirrer speed, dosing ratio and curing degree. The greater drug loaded is, the better microspheres loading is; but with the increase of drug loading rate, the entrapment efficiency increases first and then decreases. The drug release rate of the microsphere is 24.90% in 0.5 h and 84.90% in 48 h, when CMC-GMs with 4% curing agent is 32.03% in 0.5 h and 88.44% in 48 h. So Gms embedding of ceftiofur alkali are better than CMC-GM. The stability tests show that strong light, high temperature, high humidity have a great influence on the microspheres.展开更多
This study was carried out to evaluate the antibacterial activity of ceftiofur sodium as anti-infective chemotherapeutic agent belonged to the third generation of cephalosporins against different bacterial pathogens i...This study was carried out to evaluate the antibacterial activity of ceftiofur sodium as anti-infective chemotherapeutic agent belonged to the third generation of cephalosporins against different bacterial pathogens in vitro and birds. The obtained results showed that it was more effective and superior in its action than that the other compared antibacterial agents. The disc diffusion test revealed that most P. multocida isolates were highly sensitive to ceftiofur sodium with minimum inhibitory concentrations (MICs) ranging between 0.625 - 2.5 μg/ml and minimal bactericidal concentration (MBCs) equal or two folds of the MICs.展开更多
基于头孢噻呋碱性条件降解产物荧光强度更强,吐温-80能提高其降解产物荧光强度,建立测定猪肌肉及肾中头孢噻呋残留的同步荧光分光光度法。优化了降解条件(加热时间、氢氧化钠浓度与体积),讨论了缓冲溶液、表面活性剂种类及用量对降解产...基于头孢噻呋碱性条件降解产物荧光强度更强,吐温-80能提高其降解产物荧光强度,建立测定猪肌肉及肾中头孢噻呋残留的同步荧光分光光度法。优化了降解条件(加热时间、氢氧化钠浓度与体积),讨论了缓冲溶液、表面活性剂种类及用量对降解产物荧光强度的影响。结果发现:4 m L 2.0 mol/L氢氧化钠溶液,加热150 min,加3 m L柠檬酸-柠檬酸钠缓冲液(p H 4.2)和6 m L吐温-80溶液(0.023 3 mol/L),在1 cm荧光比色皿中,于发射波长λem 415 nm^550 nm内,△λ为85 nm条件下扫描测定,440.0 nm处读出荧光强度。应用加乙腈沉淀蛋白的方法对动物性食品进行预处理。在0.625μg/m L^62.5μg/m L范围内,头孢噻呋浓度与降解产物荧光强度线性关系良好,相关系数为0.999 3,检出限为270μg/kg。加标水平在144μg/kg^2 160μg/kg范围内,回收率为85.09%~87.83%,RSD为0.93%~1.54%(n=3)。建立的新方法可用于动物食品中头孢噻呋残留量检测。展开更多
基金supported by the Beijing Diary Industry Innovation Team,Chinathe Special Fund of the Chinese Academy of Agricultural Sciences Innovation Project (CAAS-FRI-06)
文摘The purpose of this study was to investigate the residue elimination of ceftiofur hydrochloride in milk of postpartum cows after intramammary infusing at dry-off. An ultra-high performance liquid chromatography-tandem mass spectrometry （UPLC-MS/ MS） method was developed and validated to detect ceftiofur hydrochloride residue in milk. Through preprocessing, ceftiofur hydrochloride was derivatized into a more stable compound dedfuroyl ceftiofur acetamide （DCA） for further analysis. The linear range of DCA was 0.1 to 50 μg kg-1. Average recoveries of DCA were 82.52-105.86％. The intra-day and interday coefficients of variation （CV） were 2.95-9.82 and 6.41-7.43％, respectively. The limit of detection （LOD） and limit of quantitation （LOQ） scores were 0.05 and 0.1 μg kg-1, respectively. These parameters showed this method was reliable and valid. Twelve cows were administrated 10 mL ceftiofur hydrochloride by intramammary infusion （corresponding to 500 mg ceftiofur） to each udder after the last milking before the dry-off period. Milk was collected from each udder of cow at 12, 24, 36, 48, 60 and 72 h after calving and was mixed for each time point and each cow, then subjected to UPLC-MS/MS analysis. The results showed, the DCA concentrations in all milk samples were less than LOQ and the maximum residue limit （MRL） 100 μg kg-1, which suggested the withdrawal time of ceftiofur hydrochloride intramammary infusion used for preventing and curing mastitis in dry cows was 0 day. The study provided guidance for the clinical applications of ceftiofur hydrochloride intramammary infusion （dry cow）.
文摘Gelatin ceftiofur alkali microsphere was prepared to observe its characteristics and evaluate preservation conditions. The glutaraldehyde was increased and the carboxylic methyl chitosan was added to improve the microsphere. The experimental results show microspheres have a better morphology surface and fairly regular structure with 4% glutaraldehyde. The average particle size is 15.84 gm and particle size distribution is narrow which shows a good uniformity. Microsphere size was affected by the stirrer speed, dosing ratio and curing degree. The greater drug loaded is, the better microspheres loading is; but with the increase of drug loading rate, the entrapment efficiency increases first and then decreases. The drug release rate of the microsphere is 24.90% in 0.5 h and 84.90% in 48 h, when CMC-GMs with 4% curing agent is 32.03% in 0.5 h and 88.44% in 48 h. So Gms embedding of ceftiofur alkali are better than CMC-GM. The stability tests show that strong light, high temperature, high humidity have a great influence on the microspheres.
文摘This study was carried out to evaluate the antibacterial activity of ceftiofur sodium as anti-infective chemotherapeutic agent belonged to the third generation of cephalosporins against different bacterial pathogens in vitro and birds. The obtained results showed that it was more effective and superior in its action than that the other compared antibacterial agents. The disc diffusion test revealed that most P. multocida isolates were highly sensitive to ceftiofur sodium with minimum inhibitory concentrations (MICs) ranging between 0.625 - 2.5 μg/ml and minimal bactericidal concentration (MBCs) equal or two folds of the MICs.
文摘基于头孢噻呋碱性条件降解产物荧光强度更强,吐温-80能提高其降解产物荧光强度,建立测定猪肌肉及肾中头孢噻呋残留的同步荧光分光光度法。优化了降解条件(加热时间、氢氧化钠浓度与体积),讨论了缓冲溶液、表面活性剂种类及用量对降解产物荧光强度的影响。结果发现:4 m L 2.0 mol/L氢氧化钠溶液,加热150 min,加3 m L柠檬酸-柠檬酸钠缓冲液(p H 4.2)和6 m L吐温-80溶液(0.023 3 mol/L),在1 cm荧光比色皿中,于发射波长λem 415 nm^550 nm内,△λ为85 nm条件下扫描测定,440.0 nm处读出荧光强度。应用加乙腈沉淀蛋白的方法对动物性食品进行预处理。在0.625μg/m L^62.5μg/m L范围内,头孢噻呋浓度与降解产物荧光强度线性关系良好,相关系数为0.999 3,检出限为270μg/kg。加标水平在144μg/kg^2 160μg/kg范围内,回收率为85.09%~87.83%,RSD为0.93%~1.54%(n=3)。建立的新方法可用于动物食品中头孢噻呋残留量检测。
