Determination of terbutaline enantiomers in human urine by coupled achiral-chiral high-performance liquid chromatography with fluorescence detection

A coupled achiral-chiral high-performance liquid chromatographic system wit h fluorescence detection at excitation! emission wavelengths of 276/306 nm has been developed for the determination of the enantiomers of terbutaline, (S)-(+)-terbutaline and (R)-(-)-terbutaline in urine. Urine samples were p repared by solid-phase extraction with Sep-pak silica, followed by HPLC. Th e terbutaline was preseparated from the interfering components in urine on Phenomenex silica column and the terbutaline enantiomers and betaxolol were resolved and determined on a Sumichiral OA-4900 chiral stationary phase. T he two columns were connected by a switching valve equipped with silica pre column. The precolumn was used to concentrate the terbutaline in the eluent from the achiral column before back flushing onto the chiral phase. For ea ch enantiomer the assay was linear between 1 and 250 ng/ml (R-2=0.9999) and the detection limit was 0.3 ng/ml. The intra-day variation was between 4.6 and 11.6% in relation to the measured concentration and the inter-day vari ation was 4.3-11.0%. It has been applied to the determination of (S)-(+)-te rbutaline and (R)-(-)-terbutaline in urine from a healthy volunteer dosed w ith racemic terbutaline sulfate. (C) 2001 Elsevier Science B.V. All rights reserved.