Estimating the solubility of organic compounds in water using electrokinetic chromatography

One of the most sought-after physicochemical properties in drug discovery, environmental assessment, chemical engineering, and food science, especially for new chemical entities, is the solubility of organic compounds in water (S_w). Experimentally determining water solubility is a time-consuming and tedious process; therefore, estimation methods are often opted for instead. These estimation approaches require prior knowledge of molecular descriptors or a combination of octanol-water partition coefficients and melting point data. In this work, we systematically evaluated the estimation of the solubility of organic compounds in water employing electrokinetic chromatography systems using the solvation parameter model system constants and screening tools cos θ and the d-parameter. The average absolute error for the water solubility estimation using identified micellar electrokinetic chromatography models in this study ranged from 0.291 for 75 mM sodium deoxycholate to 0.438 for 40 mM sodium dodecyl sulfate, with an expected prediction error for estimating log S_w of ∼0.4 log units. Identified micellar electrokinetic chromatography retention and water solubility correction models could be used for rapid screening purposes for the estimation of water solubility in various applications.