Effects of short-chain alcohols and urea on the association of tetradecyltrimethylammonium bromide surfactant and cefixime trihydrate antibiotic: Conductometric and physicochemical analysis

Abstract

This study explores the interaction of tetradecyltrimethylammonium bromide (TTAB), with an antibiotic drug, cefixime trihydrate (CMT), with a particular focus on conductivity changes as a reliable indicator of micelle formation. Influence of various alcohols (methanol (MeOH), ethanol (EtOH), 1-propanol (1-PrOH), 2-propanol (2-PrOH)), and urea on the physicochemical properties for micellization of TTAB in aq. alcohols/urea solutions of CMT was investigated. As the concentration of alcohol and urea increases, the critical micelle concentration (CMC) undergoes a notable rise, while the degree of counterion binding (β) shows a decreasing trend as a function of [alcohols]/[urea]. Elevated temperatures impede the creation of micelles, directing to an increase in the CMC, thus necessitating a higher surfactant concentration for micelle development. The alterations in free energy (∆Gmo), enthalpy (∆Hmo), entropy (∆Smo), and molar heat capacity (∆Cm0) were analyzed to evaluate the feasibility and driving forces behind the process of micelle development. The negative values of ∆Gmo indicate that the formation of micelles in the system being studied occurs spontaneously. The ∆Hmo and ∆Smo values suggest the existence of electrostatic forces (ion-dipole and H-bonding) between the components (TTAB, CMT, and alcohol) in aq. MeOH media. In contrast, hydrogen bonding, electrostatic forces, and hydrophobic interactions are involved in the solutions of the other three alcohols and urea medium. The thermodynamic parameters of transfer (∆Gm,tr0, ∆Hm,tr0, and ∆Sm,tr0) and enthalpy-entropy compensation variables were computed and discussed for TTAB micelles in the presence of CMT drug in employed solvents. The discoveries hold significant implications for drug formulation and industrial processes concerning surfactants and additives, providing valuable insights for optimizing their performance and properties.