Study on TEMPO-mediated selective oxidation of hyaluronan and the effects of salt on the reaction kinetics

• Published in: Carbohydrate research 2000-08, Vol.327 (4), p.455-461
• Main Authors: Jiang, Bo, Drouet, Emmanuelle, Milas, Michel, Rinaudo, Marguerite
• Format: Article
• Language: English
• Subjects: Catalysis; Cyclic N-Oxides - pharmacology; Dose-Response Relationship, Drug; Hyaluronan; Hyaluronic Acid - metabolism; Hydrogen-Ion Concentration; IR spectroscopy; Kinetics; Magnetic Resonance Spectroscopy; Molecular Weight; Oxidation kinetics; Oxidation-Reduction - drug effects; Perchlorates - pharmacology; Salts - pharmacology; Sodium Compounds - pharmacology; Spectrophotometry, Infrared; Spin Labels; Temperature; TEMPO
• ISSN: 0008-6215; 1873-426X; 0008-6215
• DOI: 10.1016/S0008-6215(00)00059-8

2,2,6,6-Tetramethyl-1-piperidinyloxy radical (TEMPO)-mediated oxidation of hyaluronan was studied at pH 10.2 and temperature of 0 °C with NaOCl as the primary oxidant. As with other polysaccharides, a high selectivity of oxidation was observed. The degradation of the polymer was essentially caused by the oxidation process. The primary oxidant and the pH of the reaction mixture did not alter the molecular weight of hyaluronan during oxidation. The kinetics of the oxidation process was investigated at different concentrations of reactants and the inorganic salts, NaBr, NaCl, and Na 2SO 4. An increase in the salt concentration in the mixture causes a major decrease in the rate of the oxidation, and this decrease is independent of the nature of the salt.