Freeze-Drying and Potency Value Establishment of Acellular Pertussis Vaccine for Using as National Reference Standard

Abstract

Reference standard vaccine is an important substance that must be analyzed with
sample. Currently, there is no the national reference standard vaccine for controlling the
potency assay of acellular pertussis (aP) vaccine produced in country. Therefore, national
control laboratory (NCL) and a manufacturer collaborated to produce a national reference
freeze-dried aP vaccine. The objective of this study was to fre eze-dry aP vaccine, which
contained pertussis toxin (PT) and filamentous hemagglutinin (FHA) and established the
potency value for using as a national reference standard. The p rocedures consisted of
formulating the liquid aP vaccine, freeze-drying, evaluating freeze-drying effectiveness by
preliminary testing and establishment aP potency. The result showed that the freeze-dried
aP vaccine produced in glass vials with stopper closures were tested and passed the preliminary tests including appearance, potency, antigen content, degree of adsorption, moisture content, reconstitution, pH, endotoxin content and sterility. The potency determined by mouse immunogenicity test, four assays from each laboratory, revealed that range of relative potency of PT from NCL and manufacturer were 0.8-1.2 and 0.3-0.6 with range of 95% confidence limits of 0.4-1.8 and 0.2-0.8, respectively. Range of relative potency of FHA from NCL and manufacturer were 8-1.4 and 0.6-0.9 with range of 95% confidence limits each of 0.4-2.6 and 0.4-1.2, respectively. The weighted geometric mean of relative potency of PT calculated from both labs was 0.51 with 95% confidence limits of 0.45 -0.59 while weighted geometric mean of relative potency of FHA was 0.83 with 95% confidence limits of 0.72-0.96. These values were established and announced as the potency of national reference standard aP vaccine. In conclusion, this study succeed to produced freeze-dried aP for using as the national reference standard to control potency of aP vaccine for consumers getting effective and safe vaccine according to standards