Chiral analysis of baclofen by alpha-cyclodextrin-modified capillary electrophoresis and laser-induced fluorescence detection.
An enantioselective method for baclofen (4-amino-3-p-chlorophenylbutyric acid) based on capillary electrophoresis (CE) separation and laser-induced fluorescence (LIF) detection has been developed. Naphthalene-2,3-dicarboxaldehyde (NDA) was used for precolumn derivatization of the nonfluorescent drug. alpha-Cyclodextrin (alpha-CD) was included in the buffer as a chiral selector for the separation of NDA-labeled S-(+)- and R-(-)-baclofen. Optimal resolution and detection were obtained with an electrophoretic buffer of 50 mM sodium borate (pH 9.5) containing 7 mM alpha-CD and a He-Cd laser (lambda ex = 442 nm, lambda em = 500 nm). Combined with a simple cleanup procedure, this method can be applied to the analysis of baclofen enantiomers in human plasma. The relative standard deviation (RSD) values on peak areas of a plasma sample containing 1.0 microM racemic baclofen were 6.4 and 4.9% (n = 8) for the S-(+)- and R-(-)-enantiomer, respectively. The RSD value on migration times of both enantiomers was 0.5% (n = 8). Calibration graphs for S-(+)- and R-(-)-baclofen in plasma showed a good linearity (r > or = 0.999) in the concentration range of 0.1-2.0 microM. The limit of detection of baclofen in plasma was about 10 ng/mL.
Chiang
M T
MT
Department of Chemistry, Tunghai University, Taichung, Taiwan.
Chang
S Y
SY
Whang
C W
CW
D001418:Baclofen / Q000097:blood* / Q000737:chemistry; D002138:Calibration; D003505:Cyclodextrins / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods* / Q000592:standards; D005453:Fluorescence; D006801:Humans; D007834:Lasers; D015394:Molecular Structure; D047391:alpha-Cyclodextrins
D003505:Cyclodextrins; D047391:alpha-Cyclodextrins; D001418:Baclofen; C032613:alpha-cyclodextrin