Chiral analysis of selected dopamine receptor antagonists in serum using capillary electrophoresis with cyclodextrin additives.

Dopamine D-2 receptor antagonists' eticlopride and sulpiride were determined in serum using capillary electrophoresis with cyclodextrin additives. Chiral resolution of S(-) and R(+) sulpiride and eticlopride were achieved using 2% sulfated-beta-cyclodextrin (S-beta-CD) in 20 mM citrate run buffer (pH 2.90). A 72-cm fused silica capillary operated in the reversed polarity mode voltage of 20 kV was used for the analysis. The analytes of interest were isolated from serum using a solid phase extraction procedure with recoveries in excess of 85% for all four enantiomers. The D-2 receptor antagonist (-) butaclamol was used as internal standard. The limits of detection were 0.3 and 0.1 microg/ml for S(-) and R(+) eticlopride and for S(-) and R(+) sulpiride, respectively, in 1 ml of serum. The limits of quantitation were 2 and 1 microg/ml for S(-) and R(+) eticlopride, and for S(-) and R(+) sulpiride, respectively. Calibration curves were linear over the 2-20 micro/ml range for eticlopride and 1-20 microg/ml range for sulpiride. The coefficients of determination were greater than 0.99 (n = 12 for eticlopride and n = 15 for sulpiride). Precision and accuracy of the method were 0.27-6.38 and 0.20-3.60% for S(-) eticlopride, 2.33-4.28 and 0.80-5.73%, for R(+) eticlopride, 3.46-6.84 and 0.80-4.26%, for S(-) sulpiride; and 4.71 -6.47 and 2.00-6.67%, for R(+)-sulpiride, respectively.