Optimization of Diphtheria Toxoid Absorption on Aluminum Phosphates and its Relationship with Potency

In the mid-1940s، the diphtheria toxoid (inactivated toxin) vaccine was developed via combination with tetanus and pertussis vaccines (DTP vaccine) and successfully conducted to eradication of diphtheria disease throughout the world. Optimization of diphtheria toxoid absorption on aluminum phosphates to improve the rate of absorption and increase the efficacy of vaccine was our aim. In this study، the effect of different parameters، such as initial pH، temperature and final pH، on the adsorption rate of diphtheria toxoid on aluminum phosphate gel waz studied in vitro and vivo. Purified diphtheria toxoid was used for vaccine preparation. It was adsorbed to aluminum hydroxide with different pH values (5. 0، 5. 2، 5. 4، 5. 6، 5. 8 and 6. 0) and exposed to various temperatures (4، 24 and 37°C) and adjusted to the final pH values of 6. 4، 6. 6 and 6. 8. The effective formulation was the pH of 5. 8 at the temperature of 4°C with the final pH of 6. 6. The level of antibody in the immunized animals significantly was high. It is suggested that with new formulated vaccine with the optimized conditions، can significantly make the rate of toxoid and level of antibody high in the immunized animals.