Preferential Solvation of Ibuprofen and Naproxen in Aqueous 1,2-Propanediol

The recently published study of the solubility of ibuprofen (IBP) and naproxen (NAP) in aqueous 1,2-propanediol (PG) at several temperatures had as its purpose the modeling of the solubilities in terms of the solvent composition. It did not show how these drugs are preferentially solvated by water and by PG. The inverse Kirkwood-Buff integral (IKBI) and the quasi-lattice quasi-chemical (QLQC) approaches are here applied to this problem of the preferential solvation. The interactions involved are deduced from the results.