Determination of the enantiomers of mefloquine in plasma and whole blood using a coupled achiral-chiral high-performance liquid chromatographic system.

A coupled achiral-chiral high-performance liquid chromatographic system has been developed for the determination of the enantiomers of mefloquine, (+)-MFQ and (-)-MFQ, in plasma and whole blood. The MFQ was separated from the interfering components in the biological matrix and quantified on a cyano-bonded phase, and the enantiomeric composition was determined on an (S)-naphthylurea chiral stationary phase. The two columns were connected by a switching valve equipped with a silica precolumn. The precolumn was used to concentrate the MFQ in the eluent from the achiral column before backflushing onto the chiral phase. The coupled-column system was validated and applied to the analysis of a pilot study of the pharmacokinetics of (+)- and (-)-MFQ in plasma and whole blood.