High performance liquid chromatographic enantioseparation development and analytical method characterization of the carboxylate ester of evacetrapib using an immobilized chiral stationary phase with a non-conventional eluent system

• Summary of the benefits of immobilized polysaccharide chiral stationary phases.
• Separation of the methyl ester of evacetrapib from three isomers.
• Fine-tuned conditions that resolves isomers from structurally diverse impurities.
• Ternary eluent system incorporating a mid-polarity solvent.
• Separation method withstood a rigorous characterization and ruggedness protocol.

Using multiple HPLC chromatographic modes and various chiral columns in the context of an automated screening system, a potential separation was initially identified for the methyl ester of evacetrapib and its stereoisomers using an immobilized polysaccharide-based HPLC column. The bonded nature of this column, the Chiralpak® IC, allows for enhanced separation development with a diverse solvent range not amenable to standard coated chiral stationary phases. The ternary eluent system ultimately identified provided isomer resolutions not obtainable via the more established hexane/alcohol or polar organic chromatographic modes. A systematic separation development process is described, first for the resolution of the isomers, and later incorporating five potential impurities. A robust separation system was eventually developed that effectively resolves all compounds within a reasonable analysis time.