Data were available to show that the availability to the colon of orally administered clindamycin is one-tenth of that of lincomycin. The method involves extraction of the sample, followed by solvent partitioning and solid-phase extraction for purification of the extracts. In a 90-day study of toxicity, rats received melengestrol acetate in their diet at concentrations providing 0, 0. Safety evaluation of certain food additives and contaminants. Melengestrol acetate was also fed to heifers at a dose equal to 1. No residues of cyhalothrin were detected in liver, kidney or muscle at day 3. Specifications for the identity and purity of some food colours, emulsifiers, stabilizers, anticaking agents, and certain other food additives.
The wide variation found in the maximum concentration was attributed to the effect of different food intakes. T If emergence of antimicrobial resistance is the concern, conduct tests in vitro continuous culture of faecal inocula or in vivo rodents inoculated with human flora ; challenge the model system with an antibioticresistant species and determine the concentration of the drug that does not select for resistance or the antibiotic-resistant strain when compared with absence of the drug. The limit of quantification of the analytical method was 0. Aqueous acetonitrile is used for the initial extraction and is followed by filtration. Cyhalothrin is applied topically as a pour-on formulation to cattle at a dose of up to 60ml 1. The reporting of residue concentrations on a weightper-weight basis is consistent with internationally recommended analytical protocols.
The marker residue accounted for 25% of the total residues in kidney. Pig excreta contained little unchanged lincomycin: urine contained 11-21% of the oral dose, half of which was unchanged parent compound. Unmetabolized metrifonate accounted for 6-7% of the total residues in muscle and kidney, but was not present in liver, fat or milk. Females receiving the highest dose vomited and had slightly reduced food consumption and body-weight gain, slightly increased plasma cholesterol concentrations, increased absolute and relative liver weights, and decreased absolute and relative heart weights. The drug can be administered alone or in combination with other growth-promoting 64 drugs.
Validation of the method used in the studies summarized by the Committee was based mainly on the analytical recovery of melengestrol acetate. Over the 5 days after treatment, 14 and 5. Metrifonate was administered orally to rhesus monkeys at a dose of 0, 0. The available data indicate that disruption of the barrier to colonization of the human gastrointestinal microflora is the major concern, rather than the emergence of drug-resistant populations. Evaluation of mercury, lead, cadmium, and the food additives amaranth, diethylpyrocarbonate, and octyl gallate. Safety evaluation of certain food additives.
In three other studies, the incidence of fetal malformations was unaffected. These specifications were subsequently revised and published as Specifications for identity and purity of food additives, Vol. Evidence that interconversion of the isomeric forms does not occur during metabolism in the target species. Yes Do clinical data from therapeutic use of the class of drugs in humans or data from in vitro or in vivo model systems indicate that effects could occur in the gastrointestinal microflora recommendation 1 f? The coefficient of variation of the method was consistently less than 10%. Specifications for the identity and purity of some food additives.
The recovery of lincomycin by these methods was 84-102%, depending on the tissue, with a limit of quantification of 0. Melengestrol acetate did not induce micronuclei in the bone marrow of mice exposed in vivo by intraperitoneal injection. The number of live fetuses and the mean litter and fetal weights were significantly lower at doses of 0. The results obtained for fat and liver were similar in all four treated animals and the concentrations of melengestrol acetate residues found in muscle were all close to or below the limit of quantification of the analytical method used Table 4. Dichlorvos was found in one sample. Boisseau, Director, National Agency for Veterinary Medicinal Products, French Food Safety Agency, Fougeres, France Vice-Chairman Professor A. Melengestrol acetate was embryotoxic and fetotoxic at doses of 0.
The committee, consisting of a group of internationally recognized experts thoroughly conversant with the latest scientific and technical advances in this field, points out the inherent limitations in the assessment of long-term health risks of veterinary drug residues due to the lack of unequivocal epidemiological data, the use of invalidated procedures for risk estimation, the inherent shortcomings of animal studies and other factors. The treatment schedule was considered to represent the most extreme use of cyhalothrin as the spray product. Soback, Head, National Residue Laboratory, Kimron Veterinary Institute, Ministry of Agriculture, Beit Dagan, Israel Dr R. The concentrations ranged from below the limit of quantification 0. Serum and urine from exposed workers contained the metabolites 3- 2-chloro-3,3,3-trifluoroprop-l-enyl -2,2-dimethylcyclopropanecarboxylic acid, 3-phenoxybenzoic acid and 3- 4'-hydroxyphenoxy benzoic acid. In excreta, lincomycin accounted for 60-85% of the total residues during treatment and 50-55% of the total residues 4 days after treatment. Dicyclanil and one unidentified metabolite were extracted from liver and kidney; kidney also contained descyclopropyl dicyclanil.
The occurrence of ovulation was determined by observing the periovulatory surge of luteinizing hormone, the peak of estradiol, and the increase in progesterone concentration in the luteal phase. There was no significant effect on development at any dose. Milk samples taken during treatment and at 12-h intervals for 10 milkings after treatment were analysed by a microbiological assay. A review of the technological efficacy of some antioxidants and synergists. The effects on the fetuses, observed only at the highest dose, were reduced weight, a slightly increased incidence of dilatation of the renal pelvis, and a number of mainly sternebral defects and variations due to poor or absent ossification.
Identification of metabolites in the extractable fractions proved to be difficult, because of the complex nature of the residues. Lincomycin is rapidly absorbed after parenteral or oral administration in all food animal species and is widely distributed to tissues. The effects reported are consistent with progestational and corticosteroidal activity. In the cows that received the dose of 3. When the cows were killed 16 h after the final treatment, most of the radiolabel had been eliminated in faeces 49% and urine 27 %. Of the four standard edible tissues, fat contains the highest concentrations of melengestrol acetate.
The concentration of radiolabel in plasma and in tissues distant from the treated area appeared to reach a maximum at 3 days and declined thereafter. Residues of some veterinary drugs in animals and foods. At the present meeting, data were provided on the use of dicyclanil applied as a pour-on formulation to sheep at a maximum dose of 0. Most of the metrifonate was excreted in milk during the first 12 h after treatment. At that time up to 4% of a dose was recovered from the carcasses of the rats. No consistent dose-response relationship was seen for effects on hormone concentrations.