Hyaluronic acid chemical modifications

The chemical adjustment of charge density is another potentially rewarding technique. It does, however, require either the synthesis of new polymers or the chemical modification of preformed polymers (e.g., supersulfation of hyaluronic acid [16]). This procedure has not been evaluated in our screening. 

Prestwich, G.D. et al., Controlled chemical modification of hyaluronic acid synthesis, applications, and biodegradation of hydrazide derivatives, J. Cont. Rel., 53, 93, 1998. 

Bulpitt P, Aeschlimann D (1999). New strategy for chemical modification of hyaluronic acid preparation of functionalized derivatives and their use in the formation of novel biocompatible hydrogels. J. Biomed. Mater. Res. 47 152-169. 

Key words hyaluronic acid, translational research, chemical modification, cell therapy, practical design criteria. 

Schante CE, Zuber G, Herlin C, Vandamme TF. Chemical modifications of hyaluronic acid for the synthesis of derivatives for a broad range of biomedical applications. Carbohydr Polym. 2011 85 469-89. 

Chemical Modifications, Solid Phase, Radio-Chemical and Enzymatic IVansformations of Hyaluronic Acid... 

From the chemical point of view, hyaluronan possesses four different types of functional groups acetamide, carboxylic acid, hydroxyl and terminal aldehyde. After deacetylation, a free amine could be obtained from an acetamide group. All four functionalities permit characteristic chemical reactions. Such a wide variety of possible chemical modifications creates a sharp difference between hyaluronic acid and other polysaccharides whose reactivity depends mainly upon hydroxyl groups. 

We realize that the description of the overall reactivity and chanical modifications of hyaluronan is a dense subject that could fill a separate monograph. However, this chapter will focus mainly on the chemical modifications of hyaluronan that lead to cross-linking. Such modifications play an important role for the creation of hyaluronic acid with valuable chemical and physical properties necessary for biological application of hyaluronan products. 

The problems of production and purification of hyaluronic acid are discussed in detail in Chapter 3. The comparable data of the commercial products are presented in Chapter 3 as well. The structure and rheological properties are discussed in Chapter 4. The discussion is united by a general idea about cooperative conformational transformations as the main phenomena that manifest bio-specificity of hyaluronic acid as well its unique effect of the relationships of biological properties from molecular mass. The physical and chemical methods of hyaluronan structural modification are presented in Chapter 5. It presents reactions of the macro-molecule cross-linking with bi-functional reagents as well as highly... 

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