Log P measurements show the degree to which the compound is partitioned between water and octanol (or other non-miscible solvent). To perform the log P experiments, the pKa must be known. The analysis is based on potentiometric principles, with results comparable to the "shake-flask" technique. In addition, this method covers the entire pH range so the log D at any pH value can be determined (lipophilicity profile). This technique has the advantage of a wide dynamic range of log P determination: -2.0 to 8.0 has been demonstrated. We routinely measure log P between -1.0 and 5.0 using standard procedures.
Although suitable for most
compounds, the technique is especially useful for zwitterions and problems
associated with ion-pair formation, as well as for compounds that suffer from
micro-emulsion problems in the shake-flask method. We have the capability to
perform experiments with other partitioning media such as cyclohexane, heptane,
and liposomes.
|
Sample Submittal Sheet
(PDF)