Molecular weight and structure characterization of sodium hyaluronate and its gamma radiation degradation products by flow field-flow fractionation and on-line multiangle light scattering.

A combined flow field-flow fractionation (FlFFF)/multiangle light scattering (MALS)/differential refractive index (DRI) detection method has been utilized for the size fractionation and characterization of ultrahigh molecular weight (MW) sodium hyaluronate (NaHA) samples. Separation of broad MW NaHA polymers was carried out by a frit inlet asymmetrical FlFFF channel employed with a linear field programming method followed by the on-line monitoring of light scattering at multiple angles for the calculation of MW and for the study of the conformation of NaHA samples. NaHA samples examined were: (1) two different viscosity fractions of NaHA obtained by a refinement process and (2) NaHA products of gamma radiation degradation. While the NaHA samples of two different viscosity fractions exhibited clearly different MW distributions and similar conformation, the radiation degraded NaHA samples showed a clear difference in both MW distribution and polymer structure.