Application of Centrifugal Counter-Current Chromatography to the Separation of Macrolide Antibiotic Analogues. Ii. Determination of Partition Coefficients in Comparison With the Shake-Flask Method

The separation of compounds by centrifugal counter-current chromatography (CCC) is based on the difference in partition behaviour of solutes between the two immiscible liquid phases. Therefore, Δlog K, defined as the difference of partition coefficients of the solutes, is a key criterion in the solvent system selection for the CCC. Partition coefficients (log K) of macrolide antibiotic analogues can be measured by different ways, such as direct shake-flask method or indirect HPLC analysis. However, there are also some clear limitations and shortcomings with these methods. As an alternative, a Quattro Counter-Current Chromatograph was examined to measure log K for a series of macrolide antibiotic analogues and compared with the classical shake-flask method. The experimental results shows that partition coefficients measured by CCC are highly correlated with those determined by shake-flask method. The major advantages of the CCC method are rapidity, precision, and the possibility to determine log K of analytes in mixtures. Therefore, CCC is a promising alternative to directly measure the partition coefficients of macrolide antibiotics analogues in purification process development.