Cross-linked derivatives of hyaluronic acid

A cross-linked derivative of partially N-deacetylated hyaluronic acid or derivatives thereof, comprising at least one repeating unit of formula (I):

• wherein R1 is H or a residue C1–C20, substituted or unsubstituted, derived from an aliphatic, aromatic, arylaliphatic, cycloaliphatic, or heterocyclic aldehyde, provided that the said aldehyde is liquid at room temperature;
• R2 is an aliphatic, aromatic, arylaliphatic, cycloaliphatic, or heterocyclic group, substituted or unsubstituted;
• R is OH, O−, an aliphatic, aromatic, arylaliphatic, cycloaliphatic, or heterocyclic alcoholic group, or an aliphatic, aromatic, arylaliphatic, cycloaliphatic, or heterocyclic amino group;
• the groups R3, equal or different from each other, are H, SO3−, or a residue of hemiesters of succinic acid or of heavy metal salts of hemiesters of succinic acid;
• the groups R4, equal or different from each other, are a percarboxylic group, or a group CH2OR3;
• and
• the said hyaluronic acid derivatives are selected from the group consisting of:
• partial esters of hyaluronic acid esterified with aliphatic, aromatic, arylaliphatic, cycloaliphatic, or heterocyclic alcohols;
• hemiesters of succinic acid or heavy metal salts of the hemiesters of succinic acid with hyaluronic acid or with partial esters of hyaluronic acid;
• O-sulphated hyaluronic acid and derivatives thereof;
• amides of hyaluronic acid or a derivative thereof with an aliphatic, aromatic, arylaliphatic, cycloaliphatic, or heterocyclic amine;
• percarboxylated hyaluronic acid and derivatives thereof;
• and
• hyaluronic acid salts with heavy metals.