Bilinear model for the prediction of drug solubility in ethanol/water mixtures

A new bilinear function that accounts for the disparity between the log-linear and parabolic models for cosolvent solubilization is presented, where ethanol was used as the model cosolvent. This accounts for both the initial and terminal slopes in the ethanol/water solubility profiles of semi-polar solutes. The proposed model has only two fitted parameters σ_A and σ_B, which represent the initial and terminal asymptotes in the solubility profiles. The bilinear function can also model the ethanol/water solubility profile more accurately than the log-linear model and a general parabolic model.