Semisynthetic resorbable materials from hyaluronan esterification

In recent years, research on new, biscompatible, degradable materials has s een the development of a series of modified natural polymers. Among these, a new class of materials consisting of different hyaluronan derivatives pro mises to be useful in a whole range of clinical applications thanks to thei r varied biological properties. These new materials are obtained by chemica l modification of purified hyaluronan consisting of the partial or total es terification of the carboxyl groups of this natural polymer. This review on the properties of the new materials reports some of their biocompatibility and characterization aspects based on findings from studies conducted on t he ethyl and benzyl hyaluronan eaters, two representative members of this n ew class of compounds, and is intended to arouse interest in the potential of other, as yet unexplored derivatives. From the results of a number of in vestigations, the various derivatives appear to possess different physico-c hemical properties, especially as far as the degree of hydration and polyme r stability are concerned. In addition, the type of esterification and exte nt of chemical esterification of hyaluronan considerably affects the biolog ical properties of these materials, offering a range of polymers either fav ouring or, conversely, inhibiting the adhesion of certain types of cell. (C ) 1998 Published by Elsevier Science Ltd. All rights reserved.