Chiral Separation By High-Speed Countercurrent Chromatography

Chirality is closely related with our daily life. The basic materials constituting living organisms, such as amino acids, sugars and proteins, are chiral compounds. The conversion of chiral compounds run through the entire process of metabolism. Chirality represents the most essential nature of life processes. In addition, chirality is also involved in the aspects of agricultural chemicals, food additives, beverages, medicines, materials, catalysts and so on. The study on chirality has become the focus of scientific research and development of new products. Chiral separation, especially the separation of chiral drugs, is significant in drug research and pharmaceutical industry. Though the physical and chemical properties of isomers of chiral drugs are very similar, its pharmacological and toxicological effects are different. Sometimes one of the stereoisomers has biological activity, while the other is useless or has the opposite effect. Therefore, separation of enantiomers has become a major issue. High-speed countercurrent chromatography is a generic term for support-free liquid-liquid partition chromatography, which developed in 1980's. With 30 years of development, it has been more extensively applied in the fields of biochemistry, medicine, environmental analysis and materials.Combining the chiral selectors with high-speed countercurrent chromatography has great potential in chiral separation. In this thesis, enantiomers of 1-methoxy-6-propyl-amino-5,6,7,8-tetralin and lomefloxacin hydrochloride were successfully separated by high-speed countercurrent chromatography using sulfated-p-cyclodextrin as a chiral selector.The method of separation of lomefloxacin hydrochloride by high-speed countercurrent chromatography was established. By changing the concentration of sulfonated-β-cyclodextrin in the solvent system ethyl acetate-methanol-water (10:1:10), the optimized condition was obtained as:flow rate was 1 ml/min, the concentration of sulfonated-β-cyclodextrin was 50 mmol/1, the sample was 5 mg and lower phase was mobile phase.The method of separation of 1-methoxy-6-propyl-amino-5,6,7,8-tetralin by high-speed countercurrent chromatography was established. In this method, by changing the concentration of sulfonated-β-cyclodextrin in the solvent system ethyl acetate-methanol-water (10:1:9), the optimized condition was obtained as:flow rate was 1 ml/min, the concentration of sulfonated-p-cyclodextrin was 40 mmol/1, the sample was 5 mg and upper phase was mobile phase.