In addition, as an environmentally relevant application, we obtained experimental pHdependent distribution data for a series of ionizable compounds on a passive sampler polydimethylsiloxane (PDMS) and water. For this task, monoprotic acids and bases were searched for within the 514 compounds in the article. The experimental pKa values, logDPDMS/w, at several pH values including extreme ranges (from which we were able to obtain logPN and logPI app ) were provided by the article. 101 Therefore, predictions of the distribution coefficients in the PDMS/water system to pH = 7.4 using Eq. 1 and Eq. Finally, we explored the influence of Eq 1. and Eq. 2 to predict a relevant metric used in medicinal chemistry lead optimization affairs, the lipophilic efficiency (LipE): 102 𝐿𝑖𝑝𝐸 = 𝑝𝐴𝑐𝑡 -𝑙𝑜𝑔 𝐷 #$ , [6] where logDpH stands for the distribution coefficient and pAct represents the negative logarithm of biological activity, that is, half maximal inhibitory concentration (IC50, mol/L), inhibitory constant (Ki, mol/L), or binding energy constant (Kb). Here, we searched the literature for ionizable monoacidic or monobasic drug-like molecules with both experimentally determined logDpH measurements and biological activities. In some cases, the experimental logPN, pKa, and logPI app were reported, but otherwise they were determined using ChemAxon. The LipE was then simulated using Eq 1. and Eq. 2 and compared to their experimental values.