Chiral separation of bupivacaine hydrochloride by capillary electrophoresis with high frequency conductivity detection and its application to rabbit serum and pharmaceutical injection

Conductivity detection was employed to detect the enantiomers of bupivacaine hydrochloride (Bup), which were separated by high performance capillary electrophoresis. A computer-aided technique was used to calculate the binding energies, and the interaction between Bup enantiomers and cyclodextrins (CDs) is preliminarily discussed. Factors affecting the separation efficiency such as the types and concentration of chiral selectors, running buffer, pH value, separation voltage and capillary inside diameter and length were studied. Under optimized conditions, a baseline separation of Bup enantiomers was achieved in less than 15 min in 4 mM NH4Ac-NaAc-HAc (pH 4.00) -0.48 mM sulfobutyl ether-β-cyclodextrin running buffer at a separation voltage of 12 kV. The lowest detectable concentration was 0.052 μg/mL. The proposed method was applied to chiral separation of Bup enantiomers in rabbit serum and pharmaceutical injections.