Impact of cationic surfactants on cefepime properties in aqueous medium: Micellization and characterization of microenvironment

Micellization and related thermodynamic parameters of conventional cationic surfactants (cetyltrimethylammonium bromide and dodecyltrimethylammonium bromide) at different concentrations of cefepime (0.00, 0.001, 0.005, and 0.010 mol . kg(-1)) in aqueous medium have been thoroughly assessed by means of conductivity at different temperatures (293.15-313.15 K) and fluorescence spectroscopy at temperature 298.15 K. The thermodynamic data on micellization and degree of ionization have been obtained by conductometry. The effect of drug cefepime on the CMC (critical micelle concentration) and energetics of micellization of the surfactant has also been examined. From CMC values as a function of temperature, it is observed that micellization tendency of the surfactant increases in the presence of cefepime. The applicability of fluorescence spectroscopy to study cefepime/surfactant systems has also been investigated using pyrene as a probe. The interaction of cationic surfactant with the drug changes the micropolarity of ternary system as well as the micellar assembly of surfactant. The results have been rationalized in terms of physico-chemical concepts and relations. It would therefore, be interesting to evaluate the region of micelle formation in order to assess and develop surfactant immobilized cefepime for better biological activity. (C) 2018 Elsevier B.V. All rights reserved.