Simultaneous resolution and detection of a drug substance, impurities, and counter ion using a mixed-mode HPLC column with evaporative light scattering detection

An alternative approach to developing individual potency, impurity, and counter ion methods is the simultaneous resolution and detection of the drug substance, impurities, and the counter ion in a single chromatogram. LY326315 hydrochloride was used as a model compound to demonstrate this concept. The separation was achieved using a conventional HPLC system with an Alltech mixed-mode column, a reversed phase eluant, and evaporative light scattering detection (ELSD). The mixed-mode column, which has both reversed phase and ion chromatography functionalities (e.g. phenyl/cation, C8/anion), coupled with ELSD offers a novel approach to simultaneously resolving and detecting pharmaceutical compounds and counter ions in a single chromatogram.