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Addlestone, United Kingdom

European technical requirements for veterinary vaccines are laid down in Annex 1, Title II, to Directive 2001/82/EC, as amended by Directive 2009/9/EC, and the European Pharmacopoeia (Ph. Eur.). Safety tests carried out on each batch are generally overdosage studies carried out in at least one of the most sensitive target species and by at least the recommended route of administration that poses the greatest risk. The dose administered should preferably be twice the standard dose for inactivated vaccines and ten times the standard dose for live vaccines. Each batch must also be tested to show that it will contain the appropriate potency or titer to ensure its safety and efficacy. Live vaccines are usually tested by in vitro titration, while serological or challenge tests in vaccinated animals are commonly used for inactivated vaccines, although alternative methods are encouraged if satisfactorily validated. Several amendments have been introduced into the Ph. Eur. to facilitate reduction in the severity of tests and the numbers of animals used, including: the ability to waive the batch safety test when consistency of production has been established; in vitro methods to test for extraneous viruses in live poultry vaccines; and humane endpoints for rabies vaccine potency tests. This report discusses some preliminary conclusions concerning how these changes have affected the numbers of animals used during batch control testing of vaccines released via the UK batch release scheme. © 2011. Source

Woodland R.,Veterinary Medicines Directorate
Developments in biologicals | Year: 2012

The biological nature of IVMPs leads to some unavoidable batch to batch variation in production. The potency test is part of the quality control of the finished product intended to confirm consistency of production and that each batch is formulated equivalent to batches that have been demonstrated to be efficacious. Adequate validation of potency tests is essential to ensure that the results of the assays accurately reflect the amount, titre, or potency of the active substance measured and to indicate the limitations on the accuracy of the measurements to be expected from the test used. The CVMP/IWP published their conclusions concerning validation of potency tests in a Reflection Paper in March 2010. The test validation must demonstrate a dose response and the precision of the result should enable reliable detection of a sub-standard batch. However, the inherent variability in experimental animals often leads to unacceptably wide confidence intervals for in vivo tests which limits their ability to detect slight changes of the antigen amount. The development of in vitro methods as alternatives to in vivo potency tests is encouraged. Source

Scarth J.,A Quotient Bioresearch Ltd Company | Clarke A.,A Quotient Bioresearch Ltd Company | Hands J.,A Quotient Bioresearch Ltd Company | Teale P.,A Quotient Bioresearch Ltd Company | And 2 more authors.
Chromatographia | Year: 2010

A quantitative multi-residue LC- and GC-MS-MS based assay was validated for the analysis of endogenous androgens, progestagens and oestrogens in bovine urine. The method is targeted at analytes indicative of the abuse of nandrolone, boldenone, testosterone, progesterone and oestradiol in cattle. Using a single aliquot of urine, androgens and progestagens are extracted for analysis by GC-MS-MS on a Varian 320 instrument using an enol-TBDMS derivative, while oestrogens are removed into a separate fraction using an extraction derivatisation with dansyl chloride and analysed using LC-MS-MS on a Sciex 5000 instrument. Using a standard addition calibration line approach in pooled bovine urine, the method was found to be sensitive, with limits of detection ranging from 10.9 to 160.7 pg mL-1, and was linear between the endogenous concentrations and those augmented with 3,000 pg mL-1. The method is now being applied to large numbers of animals from controlled populations in order to establish thresholds for detecting the abuse of these steroids in food production. © 2009 Vieweg+Teubner | GWV Fachverlage GmbH. Source

Chan D.,UK Environment Agency | Tarbin J.A.,UK Environment Agency | Stubbings G.,UK Environment Agency | Kay J.,Veterinary Medicines Directorate | Sharman M.,UK Environment Agency
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2012

Due to on-going concern about the occurrence of triphenylmethane dye residues in fish destined for human consumption, a depletion study of crystal violet in salmon was carried out. Atlantic salmon less than 12 months old were exposed to crystal violet in fresh water at 15°C and subsequently sampled at 1, 7, 14, 28, 63 and 91 days after exposure. The salmon were then analysed by two analytical methods. In the first method, 2,3-dichloro-5,6- dicyanobenzoquinone (DDQ) was used to oxidise leucocrystal violet to its parent form. Total parent crystal violet was then analysed by LC-MS/MS. In the second method, crystal violet and leucocrystal violet were analysed individually by LC-MS/MS without oxidation. Both methods gave comparable results for total crystal violet concentrations, with a correlation of r 2=0.69. Statistical treatment for 88 incurred salmon samples showed no significant difference between the two sets of results with t=1.68 and t crit=1.99. Up to 98% of crystal violet was metabolised to its leuco form in the salmon after 1 day of exposure and could be detected at significant concentrations (approximately 20 μgkg -1) 91 days after exposure. The depletion data also suggest that crystal violet has a half-life of approximately 15-16 days in salmon. © 2012 Crown Copyright. Source

Stephens M.J.,Veterinary Medicines Directorate | Church D.B.,Royal Veterinary College University of London | Thomson P.C.,University of Sydney
Veterinary Record | Year: 2014

Feline hyperthyroidism is a commonly diagnosed endocrinopathy that can have a substantial deleterious impact on the welfare of affected cats. This study aimed to estimate the prevalence, associated factors and geographical distribution for feline hyperthyroidism in England, using primary-care veterinary practice clinical data from the VetCompass Animal Surveillance Project. Prevalence was estimated from the overall cat cohort. Associated factor analysis used an age-matched, nested, case-control design with multivariable logistic regression. There were 2,276 cases of feline hyperthyroidism identified from 95,629 cats attending 84 practices from September 2009 to December 2011. Cases were aged 6-25 years. 3.7 per cent of cases and 9.9 per cent of controls were purebred, 56.4 per cent of cases and 56.5 per cent of controls were female, and 88.1 per cent of cases and 86.0 per cent of controls were neutered. The apparent prevalence was 2.4 per cent (95% CI 2.3 to 2.5 per cent) overall, and 8.7 per cent (95% CI 8.3 to 9.0 per cent) in cats aged 10 years or above. Burmese (OR 0.15, 95% CI 0.07 to 0.32, P<0.0001), Persian (OR 0.17, 95% CI 0.08 to 0.33, P<0.0001), Siamese (OR 0.4, 95% CI 0.21 to 0.75, P=0.004) and purebred cats overall (OR 0.33, 95% CI 0.25 to 0.42, P<0.0001) had lower odds of feline hyperthyroidism than non-purebred cats. Insured cats had increased odds (OR 1.78, 95% CI 1.56 to 2.03, P<0.001). There was little evidence of spatial variation. This study highlights feline hyperthyroidism as a high-prevalence disease in England, and reports reduced odds of diagnosis in certain breeds and purebred cats overall. Source

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