Simultaneous analysis of bambuterol and its active metabolite terbutaline enantiomers in rat plasma by chiral liquid chromatography-tandem mass spectrometry.

A chiral liquid chromatography-tandem mass spectrometry (LC-MS/MS) simultaneous stereoselective analysis of bambuterol and its active metabolite terbutaline enantiomers in Wistar rat plasma has been developed and validated. All analytes and the internal standard were extracted from rat plasma samples by liquid-liquid extraction, separated on macrocyclic glycopeptide teicoplanin column with mobile phase constituted of 20mM ammonium acetate solution-methanol (10:90, v/v) at a flow-rate of 0.4 mL/min. Detection was performed on an API 3000 tandem mass spectrometer with positive electrospray ionization in multiple reaction monitoring mode. The calibration curves in the range 1-800 ng/mL were linear and the accuracy for each analyte was within 8.0%. The intra- and inter-day precision as determined from quality control samples was less than 10.1%. The validated assay was successfully used to determine the enantiomers of bambuterol and terbutaline in rat plasma samples in the pharmacokinetic studies of rac-bambuterol.