Typhoid fever is caused by Salmonella typhi, whose capsular polysaccharide is called the Vi polysaccharide. Since the mid-1990s, typhoid vaccines including purified Vi polysaccharide were licensed in several countries and purified vi polysaccharide va...
Typhoid fever is caused by Salmonella typhi, whose capsular polysaccharide is called the Vi polysaccharide. Since the mid-1990s, typhoid vaccines including purified Vi polysaccharide were licensed in several countries and purified vi polysaccharide vaccines have been used widely around the world. The content test of the Vi antigen is important to assure the quality and consistency of purified Vi polysaccharide vaccine batches, and the immunochemical method and O-acetyl content test are used internationally. The rocket immunoelctroporesis(RIE) method, which is used for the immunochemical method, has variability of results from each person, and there is a difficulty to control the barbital reagent, which is used in a buffer, because of its psychotropic property. In this study, we intended to check the suitability of Enzyme Immunoassay (EIA) method as an alternative method which is based on a competitive method in control and release of Korean purified Vi polysaccharide vaccines and the possibility for the new content tests between manufacturers and NCL. The validation study was conducted on this new ELISA method according to ICH guideline and validation parameters such as accuracy, precision, specificity, linearity and range were all satisfied. Moreover, the results from NCL and 2 manufactures were compared to check the inter-laboratory reproducibility and showed the replaceability for the content test. Also, the O-acetyl content test, which is only conducted in a crude purified Vi polysaccharide in Korea, is recommended to test in the final bulk vaccines in European Pharmacopoeia (EP) and Official Control Authority Batch Release (OCABR). We intended to check the O-acetyl content in the final lots by Hestrin method. The suitability study was performed and the collaborative study with manufactures were conducted to decide the specification of the O-acetyl content. Hence, draft SOPs for the new content test(Competitive ELISA) and the O-acetyl content test were prepared. The new content test method and the O-acetyl content test will do for lot release after more tests and contribute to the international competitiveness and harmonization.