<p>or. Adsorbed tetanus toxoid is prepared from tetanus toxin, produced by the growth of the bacterium Clostridium tetani in a peptone-based media. The toxin is converted to tetanus formol toxoid by treatment with formaldehyde solution. Formol tetanus toxoid is then purified, sterile, filtered and adsorbed to the aluminium phosphate.Thiomersal is added as preservative.</p>