Degradation of high-molar-mass hyaluronan by an oxidative system comprising ascorbate, Cu(II), and hydrogen peroxide: Inhibitory action of antiinflammatory drugs—Naproxen and acetylsalicylic acid

Changes in dynamic viscosity of the solutions of a high-molar-mass hyaluronan (HA) were monitored using a rotational viscometer. The degradative conditions generated in the HA solutions by a system comprising ascorbate plus Cu(II) plus H2O2 were studied either in the presence or absence of a drug—naproxen or acetylsalicylic acid. Continual decrease of the dynamic viscosity of HA solution was indicative of the polymer degradation. Addition of the drug retarded/inhibited the HA degradation in a concentration-dependent manner. The characteristics of the fragmented polymers were investigated by FT-IR spectroscopy and by two different liquid chromatographic techniques, namely by size-exclusion chromatography equipped with a multi-angle light scattering photometric detector and by high-performance liquid chromatography connected on-line to a spectrofluorometer.