New cross‐linked and sulfated derivatives of partially deacetylated hyaluronan: Synthesis and preliminary characterization ;

Partial chemical deacetylation of hyaluronan (HA) has been carried out using known procedures and carefully controlled experimental conditions in order to minimize chain degradation. The sample described herein (deHA) has a degree of deacetylation of about 17%, which corresponds to what required for its further use, but a molecular weight of about 1/25 with respect to the native, starting material. Chemical gels have been prepared with different degrees of cross-linking by means of a Ugi multicomponent condensation reaction involving aqueous deHA, formaldehyde, and cyclohexylisocyanide: the gels are mechanically stable and exhibit good water uptake strongly dependent on the extent of cross-linking, as expected. deHA samples have also been selectively N-sulfated or O-sulfated: the former exhibit anticoagulant properties well exceeding those of the latter and not too inferior to heparin.