Quantitation of the diastereoisomers of L-buthionine-(R,S)-sulfoximine in human plasma: a validated assay by capillary electrophoresis.
An assay for the diastereoisomers of the biochemical modifier L-buthionine-(R,S)-sulfoximine (BSO) in human plasma has been developed using capillary electrophoresis (CE). Separation of the diastereoisomers is achieved by the micellar electrokinetic chromatography (MEKC) mode of CE. Plasma is injected directly onto the separation capillary without any extraction step, and BSO is detected directly by ultraviolet absorbance measurements at 190 nm without prior derivatization. The whole assay, including capillary conditioning, takes approximately 30 min. Intra- and inter-day R.S.D. values are approximately 7% at sample concentrations around 25 micrograms ml-1, and approximately 3% at sample concentrations around 500 micrograms ml-1. The limit of detection in plasma is 3.9 micrograms ml-1 (S/N = 2). The assay has been used to quantitate the diastereoisomers of BSO in patient samples in a pharmacokinetic study.
Sandor
V
V
Department of Oncology, McGill University, Montreal, PQ, Canada.
Flarakos
T
T
Batist
G
G
Wainer
I W
IW
Lloyd
D K
DK
D019075:Electrophoresis, Capillary; D004791:Enzyme Inhibitors / Q000097:blood; D005721:Glutamate-Cysteine Ligase / Q000037:antagonists & inhibitors; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012967:Sodium Dodecyl Sulfate; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
D004791:Enzyme Inhibitors; D012967:Sodium Dodecyl Sulfate; D005721:Glutamate-Cysteine Ligase