Process for the preparation of lyophilized, adsorbed polyvalent vaccines

A process for the preparation of lyophilized, adsorbed, polyvalent vaccine against tetanus, diphtheria and pertussis, which comprises the steps of:

• (a) concentrating tetanus, diphtheria, and pertussis antigens to a value of 5 to 15 doses of vaccine per 3 ml;
• (b) concentrating an insoluble adsorbent carrier selected from the group consisting of aluminum hydroxide gel and aluminum phosphate so that 1.75 to 3.5 mg of adsorbent carrier are employed per dose of vaccine;
• (c) adsorbing the tetanus, diphtheria, and pertussis antigens concentrated in step (a), separately or together, on the insoluble adsorbent carrier concentrated in step (b), at a pH of 3 to 6, which is not lower than the value of the isoelectric point of any of the antigens and which does not exceed a pH value at which more than 15% of the antigens adsorbed at the pH value of the isoelectric point are eluated;
• (d) adjusting the pH value to 5 to 6:
• and
• (e) lyophilizing the mixture in the presence of a protective material selected from the group consisting of proteins, polypeptides and polysaccharides.