LIQUID-CHROMATOGRAPHIC SEPARATION OF PRAZIQUANTEL ENANTIOMERS IN SERUM USING A CELLULOSE-BASED CHIRAL STATIONARY-PHASE

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