Chemical modification of alginic acid and its conjugation to tetanus toxoid.

Alginic acid from Lessonia trabeculata was treated with bromine giving a pr oduct in 72% yield with 50% of the secondary alcohol groups oxidized to ket one. The oxidized alginic acid gave Schiff bases with amines and reductive amination products in the presence of sodium cyanoborohydride. The modified products were characterized by FT-IR and Raman spectroscopies. The amidation of alginic acid with caprolactam in the presence of carboiimi de allowed the introduction of a side chain which in a second amidation, al so activated with carbodiimide, was covalently linked to tetanus toroid in 44% yield. This alginic acid modification may be used for the synthesis of glycoconjugates with antigenic properties.