Study on Plasma Concentration and Pharmacokinetics of Ornidazole in Dogs by HPLC

OBJECTIVE:To establish a method to detect the plasma concentration of ornidazole in Beagle dog,and to study pharmacokinetic characteristics of it.METHODS:6 dogs received intravenous injection of ornidazole 50 mg/kg.The blood samples were collected before administration and 0.083,0.17,0.33,0.66,1,1.5,2,3,4,6,8,10,24 and 48 h after administration.The blood sample was precipitated with acetonitrile.The plasma concentration of ornidazole was determined by HPLC.The pharmacokinetic parameters were calculated with DAS 2.0 software.The determination was performed on Hypersil BDS C18 column with mobile phase consisted of acetonitrile-0.1% phosphonic acid(18∶82)at the flow rate of 1.0 ml/min.The detection wavelength was set at 310 nm.RESULTS:The linear range of ornidazole was 0.32-64.0 μg/ml(r=0.999 1)with an average recovery of 90.35%(n=9).The limit of detection was 0.16 μg/ml,and RSDs of inter-day and intra-day were lower than 10%(n=5).The main pharmacokinetic parameters of ornidazole were as follows:cmax(31.72±13.51)μg/ml;t1/2β(5.18±2.36)h;CL(0.17±0.07)L(/h·kg);AUC0-48 h(293.53±87.32)μg·h/ml.CONCLUSIONS:The pharmacokinetics of ornidazole in Beagle dog is up to two-compartment model,and it is distributed widely and eliminated slowly.