Study On The Pharmacokinetics And Residual Elimination Of Dicyclanil Emulsion In Sheep

This paper describes a HPLC method for detecting the concentration of dicyclanil in sheep plasma.The method is used to study the pharmacokinetics and relative bioavailability of dicyclanil emulsion in sheep in comparison with foreign reference preparation Clik(?).Moreover,this paper establishes a UPLC/MS-MS method for detecting the concentration of dicyclanil and 2,4,6-Triamino-5,pyrimidinecarbonitrile in sheep tissue.Through the study on the residue of dicyclanil emulsion in sheep,it provides a reference for estimating the withdrawal period of dicyclanil emulsion in sheep,and a theoretical basis for clinical use.1 Establishment of a method for detecting the concentration of dicyclanil in sheep plasmaA HPLC method was established for detecting the concentration of dicyclanil in sheep plasma.The separation was performed on X Bridge C18 column(250 mm×4.6 mm,5 ?m)with the acetonitrile-water as mobile phase.The ditection wavelength was 267 nm,the flow rate was 1.0 mL·min-1 and the column temperature was 30?,the injection was 20 ?L.The result shows:dicyclanil has a good liner relationship when concentration is from 20 to 10000 ng·mL-1(R2>0.999).LOQ was 20 ng·mL-1,and LOD was 6 ng·mL-1.Four levels of dicyclanil were added to blank plasma at quantitative limit,bottom,medium and high(20,100,1 000,10 000 ng·mL-1),respectively.The mean average recoveries were greater than 80%with CV less than 15%.This method had high sensitivity,good reproducibility and specificity,so it can be used for the pharmacokinetics of dicyclanil in sheep.2 Study on pharmacokinetics of dicyclanil emulsion in sheepDicyclanil emulsion was compared with imported dicyclanil emulsion(Clik(?))about the pharmacokinetic characteristics and bioavailability in healthy sheep.Twelve healthy sheep were randomly divided into two groups,dicyclanil emulsion and Clik(?),male and female half.Both groups were treated with a dose of 35 mg-kg-1 at the midline of the back,collected blood at different time points in jugular vein,and separated plasma.HPLC was used to detect the concentration of dicyclanil.The pharmacokinetic parameters of dicyclanil emulsion group:T1/2?z=25.35±7.50 h,Tmax=46.00±4.90 h,Cmax=473.73±102.53 ng·mL-1,AUC0?t=20 856.38±4 178.93 ng·mL-1·h.Clik(?)group:T1/2?z=33.91±10.54 h,Tmax=44.00±6.20 h,Cmax=469.08±126.34 ng·mL-1,AUC0?t=23 475.42±6 845.78 ng·mL-1·h.The relative bioavailability was 88.84%.3 Establishment of a method for detecting dicyclanil residue in sheep tissuesA UPLC-MS/MS method was established for detecting the concentration of dicyclanil and 2,4,6-Triamino-5-pyrimidinecarbonitrile in sheep tissues.Sample tissues(muscle,fat,liver and kidney)were treated,and detected by chromatography.The result shows:the method was proved to be linear in the range of 20-1 000 ?g·kg-1 and R2>0.99,the limit of quantitative was 20 ?g·kg-1,and the lowest detection limit was 10 ?g·kg-1.Three levels of high,middle and low levels of drugs were added to the blank tissue,respectively.The recoveries in muscle,fat,liver and kidney were 70%?110%,and CV was less than 15%.This method had high sensitivity,good reproducibility and specificity,so it can be used in the study for residual elimination of dicyclanil emulsion for sheep.4 Study on the residual elimination of dicyclnail emulsion in sheepThe developed UPLC-MS/MS method in this study was applied to monitor the residue for dicyclanil and 2,4,6-Triamino-5-pyrimidinecarbonitrile in sheep tissues,and then validating the adequate withdrawal period for dicyclanil emulsion.The sheep were treated with a dose of 35 mg·kg-1 at the midline of the back,and killed four per different time point for sampling according to the scheduled time point of 1(12 h),7,14,21,35 d after administration,then quickly collect their muscles,fat,livers and kidneys.Sample tissues were be treatment and detected by chromatography.The results of residue elimination study showed that in the first 14 days of single topical use for dicyclanil emulsion,the removal of drugs was faster in all tissues.On the 35th day after administration of the drug,all tissues was below the MRL.It was proposed 45 days of off--drug period in sheep after a single dose of 35 mg·kg-1 Dicyclanil emulsion.