to easily calculate logDpH from logPN values obtained by empirical computational models. This equation was widely used in logDpH estimation methods in the SAMPL6 and SAMPL7 blind challenges, which is a large-scale comparative evaluation for drug design predictive models. Figure . Representations of the partition mechanism for a symbolic ionizable acidic molecule for both neutral (HX) and ionic (X -) species using (a) Equation 1 and (b) Equation . The theoretical partition of the charged organic species (PI,X -) was replaced by experimentally measurable apparent partitioning (P I app ) in Eq. 2.