Determination of bevantolol enantiomers in human plasma by coupled achiral–chiral high performance‐liquid chromatography

A coupled achiral–chiral high performance liquid chromatographic method was developed and fully validated for the determination of bevantolol enantiomers, (−)‐( S )‐bevantolol and (+)‐( R )‐bevantolol, in human plasma. Plasma samples were prepared by solid phase extraction with Sep‐Pak Plus C18 cartridges followed by HPLC. Bevantolol enantiomers and (+)‐( R )‐Propranolol as internal standard (IS) were preseparated from interfering components in plasma on a Phenomenex silica column and bevantolol enantiomers and IS were resolved and determined on a Chiralcel OJ‐H chiral stationary phase. The two columns were connected by a switching valve equipped with silica precolumn. The Precolumn was used to concentrate bevantolol in the eluent from the achiral column before back flushing onto chiral phase. A detailed validation of the method was performed accordingly to FDA guidelines. For each enantiomer the assay was linear between 20 and 1600 ng/ml. The quantification limits of both bevantolol enantiomers were 20 ng/ml. The intraday variation was between 1.07 and 12.64% in relation to the measured concentration and the interday variation was 0.91 and 11.79%. The method has been applied to the determination of (−)‐( S )‐ and (+)‐( R )‐bevantolol in plasma from healthy volunteers dosed with racemic bevantolol hydrochloride. hydrochloride. Chirality, 2007. © 2007 Wiley‐Liss, Inc.