Stereospecific Determination of Mefloquine in Whole Blood by HPLC

Mefloquine, as a racemic mixture, is used for the treatment and prophylaxis of malaria. Stereoselective pharmacodynamic and pharmacokinetic differences has been observed for mefloquine. In this study a modified stereoselective HPLC method is presented for determination of mefloquine (MFQ) enantiomers in whole blood. The assay involved liquid-liquid extraction of MFQ from biological fluids with methyl tert-butyl ether in the presence of sodium hydroxide and derivatization of the residue by (+)-1-(9-fluorenyl) ethyl chloroformate (FLEC) as chiral derivatizing reagent. Separation of the resulting diastereomers was performed on a Novapack C18 reversed-phase cartridge column using acetonitrile, water, glacial acetic acid (730:270:0.7, v/v/v) as the mobile phase with a flow-rate of 1 mL/min. Using 500 L of whole blood, the limit of determination was 50 ng/mL with fluorescence detection with excitation at 263 nm and emission at 475 nm for both enantiomers. This method is comparatively simple and practical for the determination of small amounts of mefloquine enantiomers.