Application of High Temperature LC to the Separation of AZD5438 (4-(1-Isopropyl-2-methyl-1H-imidazol-5-yl)-N-[4-(methylsulfonyl)phenyl]pyrimidin-2-amine) and Its Metabolites: Comparison of LC, UPLC and HTLC

A comparison is made of the separation and analysis of a test probe, AZD5438 (4-(1-isopropyl-2-methyl-1H-imidazol-5-yl)-N-4-(methylsulfonyl)phenyl]pyrimidin-2-amine), and its metabolites using conventional LC, UPLC and high temperature liquid chromatography (HTLC). LC and UPLC separations were performed using reversed-phase water:acetonitrile solvent systems whilst HTLC was performed with an entirely aqueous mobile phase, using both isothermal and temperature gradient chromatography. Substantial reductions in run times were observed with both UPLC and HTLC compared to the conventional LC approach without loss in chromatographic resolution for the major metabolites. At temperatures in excess of 100 °C, thermal degradation of some of the metabolites was observed in an isothermal separation, however, the application of a thermal gradient proved successful in maintaining the structural integrity of the analytes and simultaneously separating the parent compound and its major metabolites.