Non-ionic and cationic micelle nanostructures as drug solubilization vehicles: spectrofluorimetric and electrochemical studies

The use of colloidal organized media, such as micelles, to solubilize tetracaine hydrochloride (TC.HCl), a local anaesthetic drug, in aqueous solution has been studied by means of fluorescence spectroscopy at 298.15 K. Because tetracaine molecule is a fluorescent probe, changes in the fluorescence emission spectra of the drug when it is solubilized by the micelles enable the study of the micelles–drug association process through the calculation of the association constants. Two kinds of micelles have been selected to solubilize the drug: non-ionic micelles and cationic micelles. Complementary conductometric experiments were also done to determine the critical aggregation concentration of the surfactants in the presence of the drug. The micelle–drug association process has been also analyzed by deconvoluting the fluorescent of the drug into several Gaussian components, each of which assigned to the solubilization of the drug within different microenvironment inside and outside the cationic and/or non-ionic micelles.