ABSTRACT
CONTENTS 7.1 Introduction ..................................................................................................91 7.2 Advances in the Application of Sodium Hyaluronate
(HA-Na).........................................................................................................92 7.3 Modification of HA and Advances in the Application
of Modified Forms.......................................................................................93 7.3.1 Ionic Interaction of HA with Divalent and Trivalent
Metallic Ions.....................................................................................93 7.3.2 Complex Formation of HA with Other Functional
Polymers ...........................................................................................93 7.3.3 Covalent Modification of HA .......................................................94
7.4 Specific Key Roles of HA and its Derivatives in Therapeutic Applications..................................................................................................97 7.4.1 HA Is an Adjuvant in Drug Delivery Cryopreservation..........97 7.4.2 Drug-HA Bioconjugates .................................................................98
7.5 Conclusion and Perspective on the Future .............................................98 References ............................................................................................... 98
Hyaluronic acid (HA) is a biomacromolecule having an anionic polysaccharide chain made up of alternating N-acetyl glucosamine and glucuronic acid repeat units. A high degree of HA solubility in water is due to its presence as a sodium hyaluronate. Being a natural tissue lubricant, it has been obtained by extracting tissues and particularly cartilaginous ones. More recently, it has been produced in sufficient quantities by fermentation. Sodium hyaluronate (HA-Na) exhibits a helical conformation when present as a crystalline solid, but undergoes conformational changes upon dissolu-
