Fig. 5. pKa and log P values for various anionic counterions. Complexes were pre-formed in MQ water at a 1 : 1 charge ratio with polymyxin b. Blue diamonds indicate no precipitate was observed; green circles indicate a precipitate was observed, but was insufficiently hydrophobic for nanoprecipitation; and red boxes indicate a sufficiently hydrophobic precipitate was formed. Adapted with permission from H. Lu, P. Rummaneethorn, K. Ristroph, and R. K. Prud'homme, Hydrophobic Ion Pairing of Peptide Antibiotics for Processing into Controlled Release Nanocarrier Formulations, Mol. Pharmaceutics, 2018, 15(1), 216–225. Copyright (2017) American Chemical Society.78.
