[Separation of enantiomeric labetalol by reversed-phase high performance liquid chromatography]

A reversed-phase high performance liquid chromatographic method for the separation of labetalol enantiomers was developed. In the method, 2, 3, 4, 6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (GITC) was chosen as the reagent for pre-column chiral derivatization of labetalol to give four diastereomeric thiourea derivatives. These derivatives were efficiently separated on a Nova-Pak C18 column using V(MeOH):V(0.01 mol.L-1(pH 7.00) H2PO4(-)-HPO(4)2- buffer) = 51:49 as the mobile phase and detected by UV detector at a wavelength of 250 nm or fluorescence detector at lambda ex = 340 nm and lambda em = 440 nm. The effects of the pH of mobile phase on the retention and fluorescence absorbance are also discussed.