Stereoselective determination of R-(-)- and S-(+)-prilocaine in human serum by capillary electrophoresis using a derivatized cyclodextrin and ultraviolet detection.

A capillary electrophoresis (CE) method for the quantification of R-(-)- and S-(+)-prilocaine in human serum was developed and validated. Stereoselective resolution was accomplished using 15 mM heptakis(2,6-di-methyl)-beta-cyclodextrin and 0.03 mM hexadecyltrimethylammonium bromide (HTAB) contained in 100 mM phosphate buffer, pH 2.5. Solid-phase extraction was used as a sample preparation technique to remove endogenous interferences. A 72-cm uncoated fused-silica capillary at a voltage of 25 kV and 30 degrees C was used for the analysis. The detection limits for R-(-)- and S-(+)-prilocaine were 38 ng/ml using 1 ml of human serum and the limits of quantitation were 45 ng/ml. The calibration curve was linear over the range of 45-750 ng/ml with procainamide as the internal standard. Precision and accuracy of the method were 2.86-8.50% and 3.29-7.40%, respectively, for R-(-)-prilocaine, and 3.94-9.17% and 2.0-6.73%, respectively, for S-(+)-prilocaine. The CE method was compared to an existing chiral HPLC method in terms of sensitivity and selectivity for the routine analysis of the drug.