title: LC-MS method for the determination of albuterol enantiomers in human plasma using manual solid-phase extraction and a non-deuterated internal standard.
abstract: A sensitive enantioselective liquid chromatography-mass spectrometry (LC-MS) assay using a manual solid-phase extraction (SPE) procedure, a non-deuterated internal standard and an ion trap LC-MS was developed to measure (R)- and (S)-albuterol in plasma. Sample extraction from plasma was achieved by a manual SPE extraction procedure with methoxyphenamine added as the internal standard. Chiral separation was achieved using a teicoplanin-based stationary phase and a mobile phase consisting of methanol, acetic acid and 28% (w/v) ammonia (1000:5:1, v/v/v). Samples were analyzed by selected reaction monitoring of product ions from the protonated molecular ions. The detection limit of the assay was 0.1 ng/ml with a conservative lower limit of quantification of 0.25 ng/ml for each enantiomer. Recovery of albuterol enantiomers from plasma spiked at 10 ng/ml of racemate was determined to be 89+/-5.8% (mean+/-S.D.). Reproducibility at 10 ng/ml of racemate assessed by the coefficient of variation was found to be 6.5% (n=5). Instrument precision (measured as coefficient of variation) was 1.4% (n=5). The correlation coefficient r(2) determined from the calibration curve over the range 0.5-50.0 ng/ml racemate in plasma was 0.998. This assay allows adequate sensitivity, recovery and reproducibility for the application to studies of inhaled albuterol.
authors.affiliation: School of Pharmacy, University of Tasmania, GPO BOX 252-26, Hobart Tas 7001, Australia. glenn.jacobson@utas.edu.au
authors.forename: G A
authors.initials: GA
authors.lastname: Jacobson
authors.forename: F V
authors.initials: FV
authors.lastname: Chong
authors.forename: N W
authors.initials: NW
authors.lastname: Davies
mesh_terms: D000420:Albuterol / Q000097:blood* / Q000737:chemistry / Q000592:standards*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D013237:Stereoisomerism
chemical_list: D000420:Albuterol