Chitosan N-sulfate. A water-soluble polyelectrolyte

Chitosans having degrees of acetylation (da) of 0.04, 0.10, and 0.22, respectively, were N-sulfated under a variety of reaction conditions. The derivatives obtained ranged in degree of sulfation (ds) from 0.4 to 0.86 (± 0.05). All were soluble in water, and the rheological properties of their solutions varied markedly with da and ds values. Both ionic strength and pH had an effect on their solubility properties, and also on interactions that they exhibited with O-(carboxymethyl)cellulose, xanthan gum, and heparin. Being compatible with other polyelectrolytes such as these, the chitosan derivatives may be useful in some aqueous formulations.