The Residues And Depletion Of Clenbuterol In Animal Tissues

In this paper, we studied the residues and depletion of clenbuterol (CL) in swine urine, plasma and tissues, and the total residues and depletion of [~3H]CL in mice, and established a method for detection of CL in swine eyes by HPLC.Twenty-four swine were randomly assigned to two groups, which were fed 5 or 10 mg/kg CL dietary respectively for 30 days. The urine and blood were collected at 1 st, 2nd, 3rd, 4th, 6th, 8th, 10th, 14th, 20th and 29th day of experiment, and we collected the urine sample in the morning, noon and dusk at the 2nd, 4th, 6th, 10th and 14th day with 10mg/kg dose;Three swines from each treatment were slaughtered after withdrawal periods of 0, 3rd, 7th or 14th day, and samples of urine, blood, eyes, liver, lung, kidney, spleen and muscle were collected. We took measure of the GB/T 5009.192-2003 to detect the CL residues in the tissues using HPLC. The result shows: ① CL could be detected in urine at the first day of treatment and the quantity of CL reached peak at 3rd or 20th day after treatment in both groups, while the residues of CL with 10mg/kg dietary were much higher than those of 5mg/kg dietary;the residues of CL in the urine varied with different time plot at the same day, and the residues in the dusk and noon were much higher than those in the morning, but almost equal in the noon and dusk. ② CL could be detected in serum at the first day of treatment and quantity of CL reached peak at 10th or 29th day after treatment in both groups, while the residues of CL with lOmg/kg dietary were much higher than those of 5mg/kg dietary. ③ At 0 withdrawal periods, the concentration of CL in urine, serum, liver, lung, kidney, spleen, deltoid, lumbar muscle and Biceps Muscle of Thigh was respectively 338.6 ng/g, 54 ng/g, 243 ng/g, 514.7 ng/g, 116.8 ng/g, 66.5 ng/g, 13.8 ng/g, 11.5 ng/g and 12.1 ng/g (5mg/kg), 1417ng/g, 104 ng/g, 352 ng/g, 825.7 ng/g, 183.8 ng/g, 135.2 ng/g, 19.4 ng/g, 18.7 ng/g and 18.1 ng/g (10 mg/kg). ④ The speed of depletion in tissues varied. At 14 withdrawal periods CL could be detected in all the tissues except for the muscles (<0.5ng/g), the concentration of CL in urine, serum, liver, lung, kidney and spleen was respectively 15.1 ng/g, 1.2 ng/g, 16.1 ng/g, 17.1 ng/g, 4 ng/g and 4.6 ng/g (5mg/kg), 21.8 ng/g, 5.5 ng/g, 41.2 ng/g, 39.6 ng/g, 9.6 ng/g and 8.3 ng/g (10mg/kg). The results of this study indicated the followings: the residues of CL were high;the distribution was abroad;and the depletion of CL was slow in swine;the speed of depletion was different in different tissues. Therefore, we should select the appropriate samples to control the illegal use of CL.We also studied the total distribution, depletion and residues of [~3H]CL in mice. Total radioactive residues were measured in liver, lung, kidney, spleen, heart, brain, adipose tissue, blood, germen, gastrointestinal tract, eye and hair. The result shows that the total distribution, depletion and residues of [~3H]CL in mice is consistent with those in swine, and the residues of CL in hair is higher and the speed of depletion is the slowest, so it may be a very good target for judge the illegal use of CL, and to a certain extent, eye, liver or lung can be a target to detect CL.A new method for the determination of CL by reversed-phase HPLC with UV detection has been established initially. The range of linearity was 0.01μg/ml-10(μg/ml;the limit of detection(LOD)was 2.5ng/g;the limit of quantization (LOQ)was 5ng/g;recoveries were 70%-110%;coefficients of variation were 3.95%-8.42%. The concentration of CL in swine eyes with this method were: 1716.1 ng/g (5mg/kg)and 2981.5 ng/g (10mg/kg)at 0 withdrawal periods, and 107.2 ng/g (5mg/kg)and 385.2 ng/g (10mg/kg)at 14 withdrawal periods. Besides, the eye is a good target to help judge the illegal use of CL.Through the research, we can come to the conclusion that CL can residues in animal tissues easily and depletion is slow and different as for different tissues. Hair is a very good target to control the illegal use of CL, and to a certain extent, eye, liver or lung can be taken as a substitute of urine to judge the illegal use of CL.