When simulated moving bed chromatography (SMB) is applied to the separation of enantiomers in the pharmaceutical industry,it is necessary to produce enantiomers with higher purity due to tightened regulations by health and regulatory authorities such as FDA.Hence,many studies of SMB have focused on the possibility of further increasing separation efficiency to satisfy these requirements.Recently,several new operation strategies for improving performances of SMB have been suggested by our group.One of them is a partial-discard strategy (PD) [1].In the PD operation,small portion of product during each switching period (initial part at extract port and last portion at raffmate port) was discarded to produce high purity product.