STEREOSELECTIVE DETERMINATION OF R-(-)-PRILOCAINE 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. St ereoselective resolution was accomplished using 15 mM heptakis(2,6-di- methyl)-beta-cyclodextrin and 0.03 mM hexadecyltrimethylammonium bromi de (HTAB) contained in 100 mM phosphate buffer, pH 2.5. Solid-phase ex traction was used as a sample preparation technique to remove endogeno us 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 li mits 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 c urve was linear over the range of 45-750 ng/ml with procainamide as th e 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.