Liquid chromatographic separation of praziquantel enantiomers in serum using a cellulose-based chiral stationary...

R(-) and S(+) praziquantel (PZQ) in human serum were resolved and quantified using a stereospecific LC method. Each enantiomer and the internal standard 2-methylamino-5-chlorobenzophenone were isolated from serum using a solid-phase extraction procedure on a cyanopropyl column. Recoveries of 98.8, 93.3 and 35.4% were obtained for R(-) PZQ, S(+) PZQ, and the internal standard, respectively. A cellulose-based chiral analytical column (Chiralcel OD) was used with a mobile phase consisting of hexane-2-propanol (70:30, v/v). Linear calibration curves were obtained in the concentration range 50-1000 ng ml-1 for each enantiomer in serum. The detection limit for each enantiomer in serum using UV detection at 212 nm was 5 ng ml-1 (S/N = 3). The limit of quantitation of each enantiomer was 25 ng ml-1.