title: On-line determination and resolution of the enantiomers of ketoprofen in plasma using coupled achiral-chiral high-performance liquid chromatography.
abstract: High-performance liquid chromatography (HPLC) using a column-switching technique has been applied to the on-line determination and resolution of the enantiomers of ketoprofen (KPF) as an acidic model compound. The system incorporates a mobile phase conversion stage (LC-2), which has a dilution tube and a trapping column, between the achiral chromatography stage (LC-1) and the chiral chromatography stage (LC-3). KPF in plasma was separated from plasma components and was determined with the aid of an internal standard in LC-1. The eluate containing KPF was selectively transferred to LC-2, where the eluate was adequately diluted with a new mobile phase by using the dilution tube to reduce the influence of the mobile phase from LC-1, and KPF was reconcentrated on the trapping column. Then the KPF enantiomers were resolved in LC-3 after column-switching. This system is accurate and rapid compared with conventional HPLC. Very high sensitivity could be achieved with our system when a microbore ovomucoid column was employed in LC-3. Incorporation of LC-2 allows the most favourable mobile phases for LC-1 and LC-3 to be used independently. This method is greatly superior to usual column-switching HPLC.
authors.affiliation: Department of Physical and Analytical Chemistry, Eisai Co. Ltd, Ibaraki, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Oda
authors.forename: N
authors.initials: N
authors.lastname: Asakawa
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Sato
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D007660:Ketoprofen / Q000031:analogs & derivatives / Q000097:blood*; D013237:Stereoisomerism
chemical_list: D007660:Ketoprofen