Although of extreme importance for evaluating the effective therapeutic action, aqueous solubility data
involving drug-like molecules are scarce. Thermodynamic models can be used to estimate these solubilities,
and different models, namely activity coefficient models, have been applied for that purpose. Still,
these frequently cannot describe with accuracy broad temperature and pressure ranges, various solvent
compositions or multifunctional molecules.
Despite the success of the cubic-plus-association (CPA) equation of state (EoS) in modeling complex
systems, it has never been used for modeling the phase equilibria of drug-like molecules, explicitly
accounting for the number and nature of associating sites. In this work, aqueous solubilities of different
complex solutes, like acetamide, acetanilide, acetylsalicylic acid, adipic acid, ascorbic acid, bisphenol
A, camphor, dibenzofuran, hexachlorobenzene, hydroquinone, ibuprofen, nicotinic acid, paracetamol,
piperazine, stearic acid, sorbitol, terephthalic acid and vanillin are estimated in a wide temperature
range with the CPA EoS. Generally, the modeling results are within the experimental uncertainties
using a single temperature independent binary interaction parameter, or a solvation parameter for some
non-associating solutes. Globally, an average absolute deviation of 39% was obtained.
