| Dicyclanil is a pyrimidine-derived insect growth regulator which is used in veterinary medicine for the prevention of myiasis or fly-strike. Dicyclanil has a long lasting action which interferes with moulting and pupation in dipteran species. It is used as a pour-on formulation containing 5%(w/v) of the drug. A method to detect dicyclanil in pig plasma and tissues by high performance liquid chromatorgraphic (HPLC) with ultra violet detector was developed to analysis the pharmacokinetics index and residue of dicyclanil in pigs in this paper.1 The determination of the content of Dicyclanil by HPLCThis study is to establish HPLC method for the determination for Dicyclanil. The assay was performed on innovation TXTM column(5μm,250mmx4.6mm) with the aqueous solution of methanoic acid of one percent-acetonitrile (V:V=60:40) as mobile phase. And the detection wavelength was 270 nm, the flow rate was 0.8mL·min-1 and the column temperature was 30℃.The results indicated that the calibration curve within the range of 0.78～100μ g·mL-1 was linearly correlated, and the regression equation was A=329232C-44761, R2=0.9999. The RSD of precision were less than 2% within a run and between runs. The RSD of stability within twenty-four hours was 0.61%.The method was rapid, simple and accurate for the content determination of dicyclanil.2 preliminary studies on the pharmacokinetics of Dicyclanil emulsion in pigsThis experiment was conducted to study the pharmacokinetics of dicyclanil in pigs plasma. Dicycylanil emulsion were applicated at a single dosage of 45mg·kg-1 to six pigs. After extracted with acetonitrile, dicyclanil concentration of preparation samples was determined by HPLC method. The HPLC system consisted of innovationTM PEG(5μm, 250mm×4.6mm) column, the mobile phase was composed of ethyl acetate with one percent of acetic acid-n-hexane (V:V=45:55). The concentration-time dates were analyzed with 3p97 computer program. In present study, the standard curves for dicyclanil was linar in a range of 0.05～20μg·mL-1, linear regression coefficient was greater than 0.999, the detect limit was 0.01 μg·mL-1. adding 0.05,5 and 20μg·mL-1 dicyclanil into blank plasma, the recovery rate were (91.06±0.02)%, (93.53±0.01)% and (94.72±0.01)%, respectively, and the dicyclanil of within variation was 2.78%,2.47% and 1.39%, the dicyclanil of between variation was 3.70%,6.03% and 3.07%, respectively. The results suggested that the kinetics is fit to two compartment model with first order absorption. The main parameters of dicyclanil were as follows:T1/2k:(9.836±0.198)h, T1/2β:(20.745±1.187)h, Tpeak: (17.576±0.216)h, Cmax:(9.129±0.3)μg·ml-1,AUC:(450.010±2.993)μg·ml-1·h. The results indicated that dicyclanil was slowly absorbed and eliminated in pigs, and the concentration of plasma was high.3 Preliminary study on residues detection of Dicyclanil emulsion in pig tissuesThe method of HPLC was established to detect the dicyclanil residues in pigs. Dicycylanil were applicated at a single dosage of 45 mg·kg-1 to twenty-fourth pigs. Four pigs were killed per different time point for sampling follow the scheduled time point of 3, 7,14,21,28,35 and 42d after administration. Incise pigs’ vena cava to bleeding out to death, and then quickly collect their livers, kidneys, muscles, skin & fat and so on. Sample tissues followed the treatment procedure of homogenate, extraction, concentration, decontamination, organic membrane filtration, and finally detected by chromatography. The result revealed that:the method was proved to be linear in the range of 20～5000 μg·kg-1 and linear regression coefficient was greater than 0.999, the lowest detection limit was 10μg·kg-1. Dicyclanil was added to blank tissues respectively follow the dose levels of high, medium and low (5000,500,20 μg·kg-1), recoveries measured in muscle, liver, kidney, skin & fat were greater than 80%, RSD% of daytime and RSD% between different days(n=5) were all less than 10%. Research findings of residue elimination showed that:dicyclanil widely distributed in animal tissues. The skin & fat were as the highest in distribution, followed by kidney and liver, muscle’s distribution is the lowest. dicyclanil rapidly eliminated in the first 14 days after administration. In the 21thst st day, the concentration in muscle, kidney and liver were re-raised. Dicyclanil residue could not be detected at the 42th day. It was suggested that the withdrawal time of dicyclanil should be thirty-three days after single administration. |
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