Preparative HPLC

Preparative high-performance liquid chromatography scales the analytical HPLC technique described in Phase 3 to isolate milligram-to-gram quantities of...

Preparative high-performance liquid chromatography scales the analytical HPLC technique described in Phase 3 to isolate milligram-to-gram quantities of purified compound, using wider-bore columns and correspondingly higher flow rates and injection volumes than analytical-scale instrumentation. Preparative HPLC is typically reserved for final purification steps requiring very high purity (commonly greater than 95–99%, as required before a compound is submitted for biological testing) or for the separation of closely related impurities, including diastereomers and regioisomers, that column or flash chromatography cannot adequately resolve, and reversed-phase preparative HPLC using a C18 stationary phase is especially valuable for purifying polar or ionisable pharmaceutical intermediates that are poorly suited to normal-phase silica chromatography.