Molecular characterization of two host–guest associating hyaluronan derivatives

Molecular characteristics were determined of two high‐molecular‐weight water‐soluble hyaluronan derivatives, namely β ‐cyclodextrin (HA‐ β ‐CD) and N‐acylurea (EDC‐HA). The weight‐average molecular weight ( M w ) of HA‐ β ‐CD and of EDC‐HA, determined with a multi‐angle light scattering detector connected on‐line to a size exclusion chromatographic system, was respectively 185.3 and 86.8 kDa. However the M w value determined for the equimolar mixture of the two HA derivatives equaled 556.0 kDa. Similarly, the gyration radius of the above equimolar mixture, Rg = 80.6 nm, was signicantly greater than the values found for the single HA derivative, i.e. 40.2 nm for HA‐ β ‐CD and 23.8 nm for EDC‐HA. These data indicate that the two kinds of substituents, bound to the polymeric chains, form host–guest/inclusion complexes resulting in polymacromolecular associates/aggregates. Copyright © 2003 John Wiley & Sons, Ltd.