Stereoselective determination of R(-)- and S(+)-prilocaine in human serum using a brush-type chiral stationary phase,...

A chiral HPLC method was developed for the quantitation of R(-)- and S(+)-prilocaine in human serum. The method involves sensitive and selective detection of R(-)- and S(+)-prilocaine using normal-phase chiral HPLC on a pirkle-type naphthyl ethylamine stationary phase (Sumichiral OA-4700, 250 mm x 4 mm i.d.) at ambient temperature with a flow rate of 0.8 ml min-1. A sample clean-up procedure was used for isolation of the analytes of interest from human serum using Bond-Elut C18 columns with high recovery and selectivity. The detection limits were 4 ng ml-1 for R-prilocaine and 5 ng ml-1 for S-prilocaine. The limits of quantitation were 10 ng ml-1 for both enantiomers. Linear calibration curves in the 10-1000 ng ml-1 range showed good coefficients of determination > 0.999 (n = 3). Precision and accuracy of the method were within 4-5.8% and 1.5-4.8% respectively for R(-)-prilocaine, and 2.8-5.7% and 3.2-5.2% respectively for S(+)-prilocaine.