Effects of some surface active ionic liquids on the aqueous solubility, thermodynamic properties and fluorescence behavior of drug diclofenac sodium.

Bio-based surface-active ionic liquids (SAILs) hold considerable promise for pharmaceutical applications, particularly in enhancing the aqueous solubility and bioavailability of poorly water-soluble drugs, such as diclofenac sodium (DFS), a nonsteroidal anti-inflammatory agent classified as BCS Class II. Three distinct (2-hydroxyethyl) amine-based surface-active ionic liquids (SAILs) were synthesized. Subsequently, the interactions between DFS and these synthesized SAILs were investigated using fluorescence spectroscopy at a temperature of 298.15 K. Fluorescence spectroscopy revealed a strong interaction between DFS and SAILs. This was evident from the significant quenching of DFS's intrinsic fluorescence upon SAIL addition. The association constant and binding sites were determined. Among the tested SAILs, the [2-HEA][Ole] exhibited the strongest interaction with DFS. Furthermore, the solubility of DFS in aqueous SAILs solutions studied at temperature range of (298.15 to 313.15) K was found to increase with increasing SAIL concentration. The solubility data were accurately fitted using the e-NRTL and Wilson models. To gain deeper insights, conductor-like screening model (COSMO) calculations were performed on the studied chemicals. The obtained surface cavity volume (V) and dielectric solvation energy from the COSMO calculations provided valuable information about the intermolecular interactions. Finally, thermodynamic analysis using Gibbs and van't Hoff equations indicated that the dissolution of DFS in these systems is an endothermic process.