DETERMINATION OF THE ENANTIOMERS OF ALBUTEROL IN HUMAN AND CANINE PLASMA BY ENANTIOSELECTIVE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ON A TEICOPLANIN-BASED CHIRAL STATIONARY-PHASE

A sensitive enantioselective high-performance chromatographic (HPLC) m ethod was developed and validated to determine low levels of (-)-R and (+)-S-albuterol in plasma. Baseline resolution was achieved by using a teicoplanin-based chiral stationary phase with a polar organic mobil e phase consisting of methanol/acetonitrile/glacial acetic acid/diethy lamine, 40:60:0.3:0.2, (v/v/v/v) and a flow-rate of 1.0 ml/min. Enanti oselectivity (alpha) equaled 1.18 and resolution (R-S) equaled 1.8. By using fluorescence detection maximized at 230 and 310 nm for excitati on and emission, respectively, concentrations of each enantiomer could be measured down to 125 pg/ml from a 1-ml plasma sample. Initially, t he method was applied to plasma samples from a small single-dose inhal ation study of racemic albuterol in a human volunteer and, later, to i n vivo samples from a canine inhalation study of the single enantiomer , (-)-R albuterol, Results from the canine study showed that no chiral inversion of (-)-R-albuterol occurs in the dog. (C) 1998 Wiley-Liss, Inc.