Evaluation of SDS-Nafcillin Sodium Interactions in Glucose and Urea at Different Temperatures: Thermodynamic and Micellization Perspectives

Comprehending the interactions between drugs and surfactants is critically significant for enhancing drug delivery processes and formulating effective drug compositions. This research aims to elucidate the temperature-induced aggregation of sodium dodecyl sulfate (SDS) in combination with nafcillin sodium (NafNa); in addition to emphasizing the influence of glucose and urea on micellization. The conductivity measurements were employed to probe the interactions in the SDS-NafNa system containing aqueous glucose/urea throughout a spectrum of ambient temperatures. The addition of NafNa facilitated micellization by lowering the critical micellar concentration (CMC) values of SDS compared to those of SDS in pure water. Glucose stabilizes the water structure and enhances hydrophobic interactions, hence lowering the CMC of SDS/SDS-NafNa (1.5 mM). Urea diminishes the hydrophobic action that promotes micellization by altering the water structure, hence increasing the CMC. A U-shaped pattern has been noticed in the correlation between temperature and the CMC of SDS-NafNa in both aqueous and aqueous glucose/urea environments. Thermodynamic parameters (entropy of micellization, Δ S_m⁰ ; enthalpy of micellization, Δ H_m⁰ ; and Gibbs free energy of micellization, Δ G_m⁰ ) and physicochemical variables (CMC and counterion dissociation, α) have been used to characterize the interaction between SDS and NafNa. The negative Δ G_m⁰ values reveal that the SDS-NafNa mixture undergoes spontaneous micellization in both pure water and aqueous glucose/urea environments. Negative Δ S_m⁰ and Δ H_m⁰ values indicate the predominance of H-bonding, while positive values of Δ S_m⁰ and Δ H_m⁰ indicate hydrophobic interactions. The negative Δ H_m⁰ values could potentially be caused by London dispersion forces. The results offer critical understanding for scholars aiming to refine parameters, including temperature, concentration, and the incorporation of glucose/urea additives, to improve the effectiveness and durability of drug delivery systems.