Residue Depletion Of Cefquinome Sulfate In Broiler Tissues

Cefquinome is the fourth-generation and semi-synthetic antibiotic which has been developed solely for veterinary use,with high stability to lactamase,broad antibacterial spectrum,high blood concentration and permeability through the blood-brain barrier.It shows highly activity against gram-positive and gram-negative bacteria,but low activity against gram-negative anaerobe.It is low toxicity to kidneys.Cefquinome was used to treat respiratory tract infections in swine,cattle and horses,as well as various bacterial diseases such as mastitis and mastitis-metritis-agalactia syndrome in dairy cow.It is also used to treat infectious conjunctivitis in duck and infection caused by E.coli,Salmonella,Pasteurella and mycoplasma infections in broilers and geese.Currently Cefquinome sulfate is not approved for use in the poultry industry.Reports on residues of Cefquinome sulfate in edible tissues of broilers are rare,however,Cefquinome sulfate has been widely used in treatment of poultry diseases.In order to reduce and avoid excess residues of Cefquinome in edible tissues and products,a residue detection method for Cefquinome sulfate was established and the elimination of Cefquinome sulfate in broiler tissues was studied in this paper for providing a scientifie evidence for the determination of the withdrawal time.To establish the high performance liquid chromatography(HPLC)for determination of Cefquinome sulfate residues in broiler tissues,Cefquinome sulfate was added to the homogenized samples such as skin+fat,muscle,liver and kidney according to the volume proportion at 20:1.After being mixed samples totally,the Cefquinome sulfate was extracted from biological samples by water and acetonitrile(measuring 99 mL purified water,add 9 mL of acetonitrile,mixing it up).The supernatant wasoscillated for 15 min with 6 mL of N-hexane to degrease fat and then cleaned up on SPE column.The eluent was collected and dried under nitrogen evaporator in water at 50?,and the residues were dissolved in mobile phase.The analyte was detected by UV absorptive spectroscopy at 270 nm after separation by C18 column,with the mobile phase which the proportion of acetonitrile and water was 1:10(adjust pH to 3.0 with methanoic acid).The result showed that the lowest limits of detection(LOD,S/N?3)for Cefquinome sulfate was 0.01 ?g/g and the lowest limits of quantitation(LOQ,S/N?10)was 0.02 ?g/g in the tissues of fat+ skin,muscle,liver and kidney.The standard curve showed a good linearity in the range of 0.02?2?g/g for Cefquinome sulfate with a correlation coefficient of exceeding 0.99.The average recoveries of Cefquinome sulfate in the tissues of fat+skin,muscle,liver and kidney were 89.5%,88.8%,89.9%and 85.9%at three spiked concentration level of 0.02,0.2 and 2?g/g,respectively.The intra-day coefficient of variance was 0.86%?11.8%and the inter-day coeffient of vriance was 2.44%?11.13%which all datas met the prescribed scope.Cefquinome sulfate was stable within 48 h at room temperature,4? and-20? conditions in biological samples.The determination of the Cefquinome sulfate added to the broiler tissue homogenate were not interfered with several kinds of drugs which were similar to Cefquinome sulfate in structure and properties.The results proved that the method of HPLC established in this study was conformed to the requirements of residue detection.The method of HPLC is a specific,sensitive and precised method for detecting the Cefquinome sulfate residue in broiler tissues.Based on the established method,animal experiments were carried out in selected 100 broilers.After injected the Cefquinome sulfate at the dosage of 1 mg/kg one time every day for 7 days,the tested broilers were sacrificed respectively at 6 h,12 h and 1,2,3,4,5,6,8 days.The Cefquinome sulfate was extracted from biological samples by water and acetonitrile(11:1,v/v),according to established determination of Cefquinome sulfate residues.The result showed that the residue levels were higher in liver and kidney and lower in muscle,skin and fat.Kidney and liver were considered as the metabolically active organs.According to the regulation of maximum residue limit with Cefquinome sulfate in swine tissue.Concentration of Cefquinome sulfate in skin and fate,muscle were lower than maximum residue level(MRL)at 6 h after final administration,and in liver and kidney lower than maximum residue level at 12 h.Cefquinome sulfate residues in broiler tissues were lower than the lowest limits of detection(LOD)at 5 d after final administration.The concentration-time dates were analyzed by WT 14 software to get the withdrawal time(WT)with 95 upper tolerance limit,the WT advised in liver was 2.53 d,in kidney was 0.73 d,in skin and fate was 0 d and in muscle was 0 d.Although we suggested the withdrawal period of Cefquinome sulfate should be 3 d,the withdrawal period of medicine should be made based on the national specific situation.