Adenosine-Surfactant Interactions in Aqueous Media: Comparative Insights into Micellization, Binding, and Drug Encapsulation In SDS and BKC micelles

Understanding the interactions between crucial nucleosides like adenosine and surfactants is vital for applications in drug delivery and formulation science. This study aimed to provide a comprehensive physicochemical characterization of the interactions between adenosine and two distinct surfactants: the anionic sodium dodecyl sulfate (SDS) and the cationic benzalkonium chloride (BKC). A suite of methods, including UV-Vis spectrophotometry, conductometry, surface tension, and viscometry, was employed to elucidate the binding mechanisms and effects on surfactant self-assembly. The results demonstrate that adenosine significantly promotes the micellization of both surfactants, causing a dramatic ~40-fold reduction in the Critical Micelle Concentration (CMC) for both SDS (from 7.41 to 0.18 mM) and BKC (from 6.64 to 0.17 mM). Thermodynamic analysis confirmed that micellization in the presence of adenosine is a more spontaneous process. Binding and partitioning studies yielded high affinity constants for adenosine with both micellar systems (Kb ≈ 2.23×10⁴ M⁻¹ for SDS; Kx ≈ 2.03×10⁵ for BKC), confirming strong, spontaneous interactions. The data indicate that adenosine acts as a structural and energetic modulator of both anionic and cationic surfactant self-assembly, providing fundamental insights for the design of nucleoside-based pharmaceutical formulation