Withdrawal periods

Withdrawal periods are in days or degree days e.g. 400 degree days is 20 days at 20 °C. 

Table 7.2 Reference minimum withdrawal periods from Directive 2001/82/EC.

Produce from trial animals may not enter the food chain unless authorised by the CVM on the basis of data showing that residues will be either safe or not present in produce from animals treated at the maximum dosage with the minimum allowed withdrawal period. The CVM must be notified of the date and place of slaughter at least 10 days prior to each shipment for slaughter. The regulations also address the retention of records and the competence of study investigators. Records of drug shipments must be maintained for at least 2 years after the date of shipment. Data and results of trials must be retained for either 2 years after completion of the trial, or... 

Relapse rates after detoxification are very high. Although extension of the withdrawal period for up to 6 months does not appear to improve outcome (Sees et al. 2000), patients who have received methadone maintenance and who have a good therapeutic relationship have more successful outcomes. 

Hoechst. 1985 a. Endosulfan-active ingredient technical (Code HOE 02671 OIID970003) 13-week toxicity study in rats followed by a 4-week withdrawal period, conducted at Huntingdon Research Center, England. Hoechst Aktiengesellschaft, Frankfurt, West Germany. Unpublished study, [unpublished study]... 

Matsumoto et al. developed an immunoassay for the determination of clenbuterol in bovine and equine tissues and in bovine milk. The LOD of clenbuterol in milk, muscle, liver, kidney, small intestine, and adipose tissues was 0.1 qgkg Bovine tissue samples fortified wifh 1 qg kg of clenbuterol had recoveries that varied from 75 to 96%, but recoveries from milk samples were 99%. The authors utilized this method to estimate the clenbuterol withdrawal periods for cattle and horses. Cattle were treated with a bolus dose of either 0.3 or 0.6 qg kg body weight, by intravenous injection, and three animals were slaughtered at days 1, 6, and 9. Tissue clenbuterol levels were detectable only on day 1. Clenbuterol in milk was not detectable after a 2.5-day withdrawal period. Liver contained the highest clenbuterol concentration of the tissues measured, but this group did not measure eye tissues. 

Furosemide is a diuretic agent used to treat edema in both human and veterinary medicine and requires a 48-h withdrawal period for milk produced by cattle... 

To test for tissue storage of parathion, female rats on 50 and 100 p.p.m. diet, and appropriate control rats, were allowed water while food was withdrawn. During the withdrawal period the behavior of the treated and control rats was typical of starvation with no evidence of parathion toxicity. Death was neither hastened nor delayed. 

The withdrawal period between the last administration of an See allopathic veterinary medicinal product to an animal under Sections normal conditions of use, and the production of organically 8.2.5 and produced foodstuffs from such animals, is to be twice the 8.2.6 legal withdrawal period or, in a case in which this period is not specified, 48 hours. 

No detectable residues in milk and tissues, except liver (0.01 mg/kg FW) liver residues remained detectable after a 7-day withdrawal period No detectable residues in milk and tissues, except liver (0.08 mg/kg FW) liver residues remained detectable after a 7-day withdrawal period Liver residue of 0.54 mg/kg FW remained elevated after a 7-day withdrawal period residues in milk reached 0.013 mg/L within the first few days of feeding and declined to nondetectable (ND) levels after a 4-day withdrawal period No detectable residues in any tissue. Tb 1/2 of 4-5 days in manure manure gave >95% control of larvae of the face fly, Musca autumnalis No detectable residues in any tissue except omental fat (0.1 mg/kg FW). No houseflies (Musca domestica) or face flies developed in manure No detectable diflubenzuron residues in heart, muscle, or kidney 130 pg/kg FW in liver about 250 pg/kg FW in subcutaneous fat... 

The future development of aminoglycosides for use in veterinary medicine will depend on two main factors. The first is the cost of producing them as the synthetic process is expensive. The second is depdendent on discovering an aminoglycoside that does not accumulate and remain in kidney tissue for prolonged periods, resulting in a shorter withdrawal period for food producing animals (11). 

Certain of the chemotherapeutics. for example the sulfa drugs, have been of greater concern from the point of view of tissue residues. Though there is no evidence that the sulfa residues found in pork livers or kidneys has or would cause human health problems, they are violative by our present standards. Therapeutic use (high dosages) of antibiotics are more likely to result in residues than are feed additive uses, but it is important that only approved levels and required withdrawal periods be adhered to for all drugs. 

Residual antibiotics. With the widespread use of antibiotics in feeds the occurrence of residuals in milk, meat and eggs becomes inevitable. These residuals result primarily from failure by the producer to adhere to adequate withdrawal periods following the use of the antibiotics. In a review by Katz ( ), residual antibiotics were found in all animal species marketed in 1976 - 1978. 

There is an additional protection against residues, because antibiotics in meat tend to be destroyed by cooking.. For example, Broquist and Kohler found that chicken breast muscle containing 12 parts per million of chlortetracycline had 0.14 parts per million after roasting at 230 C for 15 minutes and no detectable amounts after half an hour. The original level of 12 ppm was about 60 times as high as would be produced by 400 ppm in the animal feed, without a withdrawal period W. The UK Swann Committee reported that the only possible effect of residues on consumers arose from penicillin in milk from cows treated for udder infections in which the withdrawal time for the antibiotic had not been observed. Cases of skin rashes were reported from the consumption of such milk by sensitive patients. The Committee commented that "there are no known instances in which harmful effects in human beings have resulted from antibiotic residues in food other than milk" ( ) ... 

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