title: Reversed-phase high-performance liquid chromatographic separation of the stereoisomers of labetalol via derivatization with chiral and non-chiral isothiocyanate reagents.
abstract: The antihypertensive agent labetalol is a mixture of two racemates. We report reversed-phase high-performance liquid chromatographic (HPLC) methodology for the separation of the four stereoisomers of labetalol via derivatization with the chiral reagent (4S-cis)-2,2-dimethyl-5-isothiocyanato-4-phenyl-1,3-dioxane. The derivatives were separated on octadecylsilane columns with a methanol-ammonium phosphate buffer mixture as mobile phase. Separations of the diastereomeric forms of labetalol were achieved with the non-chiral derivatizing reagents benzyl isothiocyanate and 1-naphthalenemethyl isothiocyanate. In all cases the derivatives of the R,S/S,R forms eluted before those of the R,R/S,S forms. Isothiocyanates may have general utility in stereoisomer separations of amines by HPLC.
authors.affiliation: School of Pharmacy, University of Colorado, Boulder 80309.
authors.forename: D M
authors.initials: DM
authors.lastname: Desai
authors.forename: J
authors.initials: J
authors.lastname: Gal
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D017879:Isothiocyanates; D007741:Labetalol / Q000032:analysis* / Q000737:chemistry; D008968:Molecular Conformation; D013237:Stereoisomerism; D013861:Thiocyanates
chemical_list: D017879:Isothiocyanates; D013861:Thiocyanates; C037152:isothiocyanic acid; D007741:Labetalol