Characterization of drug–chitosan interaction by 1H NMR, FTIR and isothermal titration calorimetry

Electrostatic interaction between opposite charge of drugs (insulin and benzoic acid) and chitosan was studied by 1H NMR, FTIR and isothermal titration calorimetry (ITC). No ionic interaction between the carboxyl group of benzoic acid and the amine group of chitosan could be detected. There was a minor change in the FTIR spectra of insulin–chitosan microparticles made of different concentrations of insulin. Exothermic heat of reaction between...