Aluminum hydroxide adjuvant produced under constant reactant concentration

Area of Science:

• Materials Science
• Immunology
• Chemical Engineering

Background:

• Aluminum hydroxide adjuvant (AlO(OH)) enhances vaccine immunogenicity by adsorbing antigens.
• Its unique crystalline structure with high surface area is key to its function.
• Optimizing synthesis conditions is vital for stability and protein binding capacity.

Purpose of the Study:

• To determine chemical and thermal conditions for synthesizing stable aluminum hydroxide adjuvant.
• To achieve high protein adsorptive capacity in the synthesized adjuvant.
• To identify effective stabilization methods for long-term use.

Main Methods:

• Precipitation of aluminum hydroxide adjuvant under varying molar ratios (OH/Al), NaCl concentrations, and temperatures.
• Assessment of adjuvant stability and protein adsorptive capacity over 12 weeks.
• Evaluation of stabilization techniques including post-precipitation NaCl addition and hydrothermal treatment.

Main Results:

• High NaCl concentration and temperature favored AlO(OH) formation over crystalline Al(OH)3.
• Newly formed AlO(OH) was unstable, converting to crystalline forms at room temperature.
• Hydrothermal treatment at 110°C for 4 hours stabilized the adjuvant, maintaining high protein adsorption for 12 weeks.
• NaCl stabilization was impractical due to hypertonic requirements.

Conclusions:

• Hydrothermal treatment is an effective method for stabilizing aluminum hydroxide adjuvant.
• Stabilized adjuvant maintains high protein adsorptive capacity, essential for vaccine efficacy.
• Optimized synthesis and stabilization are critical for developing reliable vaccine adjuvants.