CHIRAL HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF OXPRENOLOL IN PLASMA

A sensitive, stereospecific high-performance liquid chromatographic as say for oxprenolol enantiomers in rat plasma was developed, using a ch iral derivatization agent. Racemic oxprenolol and the internal standar d (racemic propranolol) are extracted with dichloromethane after alkal inization of the plasma. Quantitation of R(+)- and S(-)-oxprenolol is based on derivatization with the chiral agent S(-)-1-(1-naphthyl)-ethy l isocyanate, followed by chromatographic separation on a C-18 reverse d-phase column, with fluorometric detection (excitation at 226 nm, emi ssion at 333 nm). The assay is reproducible as judged by a coefficient of variation of less than 17.5% for bath enantiomers at all concentra tions used. Preliminary experiments in the rat demonstrate that the me thod is sufficiently sensitive for pharmacokinetic studies in that spe cies.