A high performance liquid chromatographic method for the determination of albuterol enantiomers in human serum using solid phase extraction and chemical derivatization

A high performance liquid chromatographic method was developed for the simultaneous assay of R (−)‐ and S (+)‐albuterol in human serum. The assay involves solid phase extraction as a sample clean‐up step and derivatization of racemic albuterol to its diastereomeric thioureas with 2,3,4,6‐tetra‐ O ‐acetyl‐α‐D‐glucopyranosyl isothiocyanate. Chromatographic separation was accomplished under isocratic conditions using an octadecylsilane column and a mobile phase consisting of 29:71 acetonitrile:distilled water containing 0.1% triethylamine, pH 4.0 (adjusted with concentrated phosphoric acid) at a flow rate of 0.8 mL/min. The diastereomers were detected using a fluorescence detector set at 223 nm excitation and no emission filter. Racemic bamethane was used as internal standard. Drug to internal standard peak‐height ratios were linear over a 2–20 ng/mL range for each enantiomer. The limit of detection of each analyte was 1.0 ng/mL ( S / N = 3 ).