Determination of salbutamol enantiomers in human plasma and urine by chiral high-performance liquid chromatography.

Enantiomers of salbutamol were directly separated (Rs = 1.16) and quantitated at therapeutic concentrations after solid-phase extraction from human plasma and urine by normal-phase high-performance liquid chromatography on a chiral column with fluorescence detection. The assay was linear for each enantiomer between 1.25 and 500 ng ml-1 and had a minimum limit of detection of 250 pg ml-1. A 3-ml plasma or 1-ml urine sample was required for quantitation at therapeutic doses. Inter-day variation was 5.0% for S-(+)- and 6.5% for R-(-)-salbutamol. The assay was used to compare enantioselective disposition after single doses of racemate by the intravenous, oral and rectal routes.