Optimization of HPLC method for determination of Abraham solvation parameters of pharmaceuticals

Abstract

Abraham solvation equation (Absolv) is a popular and well-established approach for modeling solute partitioning between phases of different polarity, which finds its applications in both organic chemistry and biomedical fields. Parameters constituting this equation are good quantitative descriptors of solute hydrogen bonding potential that are useful for QSAR modeling of more complex chemical and biological phenomena. Numerous studies dealing with fast determination of Abraham descriptors using HPLC can be found in the literature, but these mostly focus on small un-ionizable industrial and environmental chemicals, whereas experimental data for pharmaceutical molecules are clearly lacking. In the current study we build upon a previously published chromatographic approach, aiming to adapt the method to ionizable drug-like compounds, and optimize it by reducing the number of required HPLC columns. The analysis involves determination of the overall H-bond acidity (A), H-bond basicity (B) and polarity/polarizability (S) descriptors for 62 pharmaceutical molecules with previously unpublished parameter values.