Effect of metabisulphite on residual free formaldehyde estimations

Inactivated Viral Vaccines

Inactivated vaccines have been used for over a century to induce protection against viral pathogens. This established approach of vaccine production is relatively straightforward to achieve and there is an augmented safety profile as compared to their live counterparts. Today, there are six viral pathogens for which licensed inactivated vaccines are available with many more in development. Here, we describe the principles of viral inactivation and the application of these principles to vaccine development. Specifically emphasized are the manufacturing procedure and the accompanying assays, of which assays used for monitoring the inactivation process and preservation of neutralizing epitopes, are pivotal. Novel inactivated vaccines in development and the hurdles they face for licensure are also discussed as well as the (dis)advantages of inactivation over the other vaccine production methodologies.

An international collaborative study on a method for determination of formaldehyde in veterinary vaccines

An international collaborative study of a quantitative colorimetric method for determination of formaldehyde in veterinary vaccines was conducted on a series of replicate, blinded veterinary vaccine products by 15 laboratories in three regions: North America, Europe and Japan. Participants conducted determinations using a modification of a method from the European Pharmacopoeia, a colorimetric method based on the reaction of formaldehyde with methylbenzothiazolone hydrazone hydrochloride. For this study, three licensed vaccine products containing formaldehyde were revialed, randomly numbered, tested for uniformity and distributed by one of the participating laboratories through regional coordinators to collaborators. One of the revialed products was spiked with a known amount of formaldehyde and included in the test series. Results along with all raw data were returned to the distributing laboratory for consolidation and statistical treatment. For the modified method spike recovery was 101% and reproducibility (inter-laboratory variation expressed as relative standard deviation) ranged from 18.0 to 8.0% for respective formaldehyde concentrations of 0.28 to 1.07 g/l. Based on the study, the method was proposed by the Biologicals Working Group of the International Cooperation on Harmonization of Technical Requirements for Registration of Veterinary Medicinal Products (VICH) as a candidate for the VICH Guideline standard method for residual formaldehyde.