Accessing robust vaccine coformulation stability by single adjuvant detection on a microelectrode.

Area of Science:

• Vaccine development
• Nanotechnology
• Analytical chemistry

Background:

• Assessing the shelf-life stability of coformulated vaccines is crucial for next-generation vaccine development.
• Current methods like dynamic light scattering have limitations in resolving subtle particle differences at the nanometer scale.
• The US Food and Drug Administration's review of SHINGRIX™ highlighted the importance of coformulation stability.

Purpose of the Study:

• To introduce and validate stochastic electrochemistry as a novel method for analyzing individual vaccine particles.
• To compare the capabilities of stochastic electrochemistry with dynamic light scattering for vaccine stability assessment.
• To investigate the stability of SHINGRIX™ vaccine components at the single-adjuvant level.

Main Methods:

• Stochastic electrochemistry was employed by introducing hexacyanoferrate(II/III) into vaccine solutions.
• Discrete current drops were observed upon particle collision with a microelectrode, correlating with particle size.
• The technique was applied to streptavidin-functionalized beads and SHINGRIX™ vaccine components (AS01_B adjuvant and glycoprotein E).

Main Results:

• Stochastic electrochemistry successfully analyzed individual particles and their interactions at vaccine-level concentrations.
• A direct comparison with dynamic light scattering demonstrated the superior resolution of stochastic electrochemistry for SHINGRIX™ components.
• The study provided a quantitative kinetic understanding of coformulation stability not achievable with current methods.

Conclusions:

• Stochastic electrochemistry offers a powerful new approach for detailed analysis of vaccine coformulation stability.
• This method provides insights into individual particle properties crucial for next-generation vaccine design.
• The technique enhances the ability to predict and ensure long-term vaccine efficacy and safety.