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ABSTRACT: The European Pharmacopoeia (Ph. Eur.) monograph for varicella vaccine (live) (0648) requires a vial of an appropriate reference material to be titred in triplicate to validate each assay and the virus concentration of the reference preparation is monitored using a control chart to determine the assay consistency. An international collaborative study involving 9 participants from 7 countries and including both OMCLs and manufacturers was carried out to establish a common reference material for this purpose and establish a Ph. Eur. Biological Reference Preparation. Two candidate reference preparations (X and Y), obtained from 2 different EU manufacturers, were assayed by the participants using their in-house PFU assay methods. Both candidates were found to be suitable for this purpose. Based on logistical considerations, candidate X (4.37 log(10)0 PFU/vial) has been established as BRP batch 1 of varicella vaccine (live) and was adopted at the June 2009 session of the European Pharmacopoeia Commission for immediate use. Candidate Y (3.82 log(10) PFU/vial) will be established as BRP batch 2 upon depletion of BRP batch 1 provided that the stability data supports this.
Pharmeuropa bio & scientific notes. 10/2009; 2009(1):41-54.
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ABSTRACT: Some of the guidelines for potency testing of vaccines issued by regulatory bodies such as the European Pharmacopoeia (EP) and WHO are detailed and stringent (e.g. EP monograph for Newcastle Disease (ND) Vaccine (inactivated)), whereas others only stipulate that the number of animals used should be sufficient to meet the required accuracy (e.g. EP monograph for Hepatitis A vaccine (inactivated)). Simulation studies in our laboratory using historical ND potency test data indicated that the number of animals specified in the monograph is too high; a considerable reduction from 10 to seven animals per group does not substantially influence the precision of the results. Multipoint models (e.g. EP monograph for Tetanus Vaccine (adsorbed)) require at least three dilutions per vaccine for testing for response linearity. However, when historical data clearly show that in the range used the response curves are linear, it is superfluous to verify this in every test. Furthermore, linearity has little priority for a valid parallel line assay calculation. A simulation study using historical Diphtheria potency test data showed that calculations using two dilutions per vaccine in relatively small groups of animals produced results comparable to those obtained from the full assay. This procedure still enables calculation of the relative potency, in contrast to the 1 + 1 method, which gives only a pass or fail result, while the number of animals required is only slightly higher. This method could be applied in cases where the 1 + 1 method fails. In conclusion, by providing guidelines on methods in which proven consistency in production and testing may be taken into account, manufacturers are more stimulated to look for other (cheaper) ways to test the potency of a vaccine using less animals.
Developments in biological standardization 02/1999; 101:255-60.
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Developments in biological standardization 02/1996; 86:323-4.
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Developments in biological standardization 02/1996; 86:335.
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ABSTRACT: An interlaboratory validation study was carried out in seven laboratories to evaluate the suitability of in vitro serological assay systems for the assessment of the potency of tetanus toxoid in single and multicomponent vaccines for veterinary use. Nine commercial vaccines and one experimental tetanus toxoid preparation were selected for immunization purposes according to Method A of the European Pharmacopoeia. Levels of tetanus antibodies in guinea-pig and rabbit serum samples were estimated by indirect ELISA, toxin binding inhibition (ToBI) test, passive haemagglutination (HA) test and by the prescribed standard toxin neutralization (TN) test in mice. Estimates of potency obtained by in vitro tests and by TN test were in good agreement for the various vaccines tested and for antibody levels of individual serum samples in the range 2.6 IU/ml to 266 IU/ml. Significant (P < 0.05) intralaboratory variation occurred less frequently for ELISA and ToBI test than for HA test. The frequency of significant (P < 0.05) interlaboratory variation was acceptable for the ELISA and the ToBI test but greater variation was observed for the HA test. It is concluded that the ELISA and ToBI tests are suitable in vitro assay systems for assessing the potency of tetanus toxoid in batches of single and multicomponent vaccines for veterinary use. Rigid standardization of the HA test is essential before this test can be used for the same quality control purpose.
Biologicals 10/1994; 22(3):257-68. · 1.70 Impact Factor
