Study of the interaction between glucosamine hydrochloride and sodium dodecylsulphate micelles using conductometric, isothermal calorimetry, zeta-potential titrations, and NMR NOESY

Abstract

The aim of this work was to investigate the in uence of an anti-in ammatory agent, the bulky counterion named glucosamine (Gl+) , in sodium dodecylsulphate (SDS) in 2 ways: 1) by titration of SDS solutions with different concentrations of Gl+ ; and 2) by titration of Gl+ with SDS solution with concentration close to the critical micellar concentration (cmc) (7.7 mM). In procedure 1, micellisation study by isothermal titration calorimetry (ITC) showed that the increase in Gl+ concentration reduces the cmc and the micellisation enthalpy. Increasing of the micellisation entropy was also observed, suggesting desolvation of micellar structures as a consequence of electrostatic attraction with Gl+ ions. In procedure 2, titration of Gl+ with SDS solution at 7.7 mM showed the existence of 3 distinct ranges of glucosamine/SDS concentrations, which were attributed to I) Gl+ inducing micellisation, II) neutralisation of the micelles, and III) competition between the ions themselves in the micellar surface. © Tubitak.