title: Application and comparison of high-speed countercurrent chromatography and high performance liquid chromatography in preparative enantioseparation of α-substitution mandelic acids.
abstract: Preparative enantioseparations of α-cyclopentylmandelic acid and α-methylmandelic acid by high-speed countercurrent chromatography (HSCCC) and high performance liquid chromatography (HPLC) were compared using hydroxypropy-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as the chiral mobile phase additives. In preparative HPLC the enantioseparation was achieved on the ODS C18reverse phase column with the mobile phase composed of a mixture of acetonitrile and 0.10 mol L-1phosphate buffer at pH 2.68 containing 20 mmol L-1HP-β-CD for α-cyclopentylmandelic acid and 20 mmol L-1SBE-β-CD for α-methylmandelic acid. The maximum sample size for α-cyclopentylmandelic acid and α-methylmandelic acid was only about 10 mg and 5 mg, respectively. In preparative HSCCC the enantioseparations of these two racemates were performed with the two-phase solvent system composed ofn-hexane-methyltert.-butyl ether-0.1 molL-1phosphate buffer solution at pH 2.67 containing 0.1 mol L-1HP-β-CD for α-cyclopentylmandelic acid (8.5:1.5:10, v/v/v) and 0.1 mol L-1SBE-β-CD for α-methylmandelic acid (3:7:10, v/v/v). Under the optimum separation conditions, total 250 mg of racemic α-cyclopentylmandelic acid could be completely enantioseparated by HSCCC with HP-β-CD as a chiral mobile phase additive in a single run, yielding 105-110 mg of enantiomers with 95-98% purity and 85-90% recovery. But, no complete enantioseparation of α-methylmandelic acid was achieved by preparative HSCCC with either of the chiral selectors due to their limited enantioselectivity. In this paper preparative enantioseparation by HSCCC and HPLC was compared from various aspects.
authors.affiliation: College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, 310032, China ; Laboratory of Bioseparation Tecnology, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Shengqiang
authors.initials: S
authors.lastname: Tong
authors.affiliation: College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, 310032, China.
authors.forename: Hu
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, 310032, China.
authors.forename: Mangmang
authors.initials: M
authors.lastname: Shen
authors.affiliation: Laboratory of Bioseparation Tecnology, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Ito
authors.affiliation: College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, 310032, China.
authors.forename: Jizhong
authors.initials: J
authors.lastname: Yan
keywords: High performance liquid chromatography; High-speed countercurrent chromatography; Preparative enantioseparation; α-Cyclopentylmandelic acid; α-Methylmandelic acid