Solubility prediction from first principles: a density of states approach

Solubility is a fundamental property of widespread significance. Despite its importance, its efficient and accurate prediction from first principles remains a major challenge. Here we propose a novel method to predict the solubility of molecules using a density of states (DOS) approach from classical molecular simulation. The method offers a potential route to solubility prediction for large (including drug-like) molecules over a range of temperatures and pressures, all from a modest number of simulations. The method was employed to predict the solubility of sodium chloride in water at ambient conditions, yielding a value of 3.77(5) mol kg-1. This is in close agreement with other approaches based on molecular simulation, the consensus literature value being 3.71(25) mol kg-1. The predicted solubility is about half of the experimental value, the disparity being attributed to the known limitation of the Joung-Cheatham force field model employed for NaCl. The proposed method also accurately predicted the NaCl model's solubility over the temperature range 298-373 K directly from the density of states data used to predict the ambient solubility.