We characterized ultrahigh molecular weight sodium hyaluronate (NaHA) and blended pharmaceutical products containing NaHA using flow field-flow fractionation and multiangle light scattering-differential refractive index (FlFFF-MALS-DRI). NaHA is a water-soluble polysaccharide with a range of molecular weights (MW; 10(5)~10(8) Da) that is found in body fluids and tissues. NaHA is also used commercially in pharmaceutical and cosmetic applications. We used a frit inlet asymmetrical FlFFF channel to separate aqueous polymers according to their hydrodynamic size, and we used on-line measurements of light scattering to obtain the MW distribution (MWD) as well as structural information about NaHA in aqueous solution. In this study, we investigated NaHA and anti-adhesive blend mixtures of NaHA (a commercial NaHA blend mixture containing sodium carboxymethyl cellulose and a new blend with hydroxyethyl starch (HES)) to determine the molecular weight distribution MWD of NaHA and the blend mixtures and to obtain structural information about these compounds in aqueous solution. We also examined the characteristics of NaHA-HES-polylactic-co-glycolic acid film products exposed to gamma radiation for sterilization purposes.