Quantum chemistry calculation aided design of chiral ionic liquid-based extraction system for amlodipine separation

Amlodipine is a widely used medication in treating hypertension, which is also known as a chiral compound. So far efforts have been made to obtain optically pure (S)-amlodipine because (R)-amlodipine has poor efficacy and is related to undesirable side effects. However, the available separation methods for amlodipine are still unsatisfactory. Recently, chiral separation has become a promising application of chiral ionic liquids (CILs), because the structural designability enables them adjustable separation efficiency for specific tasks. In this work, a high-efficient CIL-based liquid-liquid extraction system was developed for racemic amlodipine separation with the assistance of quantum chemistry calculations. Enantioselectivity up to 1.35 achieved by the novel system at 298.15 K is significantly higher than other available extraction systems. Moreover, the recycling of CIL can be easily realized by backward extraction of amlodipine, which is important for the industrial application of CILs.