ASSESSING THE QUALITY OF THE STANDARD BATCH OF TETANUS TOXIN TeToxVn0117 FOR POTENCY CONTROL TEST OF TETANUS COMPONENT AND PURIFIED TETANUS ANTITOXIN SERUM

Abstract

The potency of tetanus vaccines is determined by challenge method and the titer of purified tetanus antitoxin serum (SAT) which is identified by the toxin neutralization method. Both of them require a standard tetanus toxin which was titrated to estimate virulence units either LD50 (challenge method) or L+/10 (for toxin neutralization method). To meet the requirements, a standard batch of tetanus toxin TeToxVn0117 was prepared and then evaluated its quality as a secondary standard sample used for tetanus potency testing and SAT serum titration. The study aimed to assess the quality and stability of the standard batch of tetanus toxin TeToxVn0117. The LD50 stability of the toxin batch was estimated annually from 2018 to 2023, and monitored through back titration of the challenge toxin in the tetanus potency test. The results showed that we produced 750 tubes of TeToxVn0117 toxin reaching an average of 417,721 LD50 units and an average of 223 L+/10 units. TeToxVn0117 toxin is stable after 6 years of storage at temperatures ≤-40^oC, suitable for utility in the potency of tetanus and titrate SAT serum titers test.