Optimization of the formulation for a candidate lyophilised tetanus toxoid reference preparation

Area of Science:

• Biotechnology
• Vaccinology
• Analytical Chemistry

Background:

• Tetanus toxoid is crucial for standardizing vaccine production assays.
• Establishing antigenic purity requires reliable reference materials.
• Existing standards may need replacement to ensure continued vaccine quality.

Purpose of the Study:

• To develop and characterize a new primary reference material for tetanus toxoid.
• To assess the stability and suitability of various formulations for lyophilization.
• To identify an optimal formulation for a World Health Organization (WHO) International Standard (IS).

Main Methods:

• Assessed multiple tetanus toxoid formulations, followed by lyophilization.
• Measured relative Lf (flocculation) content using Ramon flocculation, SRD, and ELISA assays.
• Evaluated formulation stability through accelerated degradation studies and thermal analysis.

Main Results:

• Glycine-containing formulations were unsuitable for flocculation tests.
• Sorbitol and trehalose formulations demonstrated suitability.
• The trehalose/sodium chloride formulation exhibited superior stability and performance, leading to its adoption as a WHO IS.

Conclusions:

• The trehalose/sodium chloride formulation is optimal for a tetanus toxoid reference standard.
• Lyophilization screening using thermal analysis and microscopy aids in biological reference material development.
• The new WHO IS ensures accurate standardization in tetanus toxoid vaccine production.