Chiral separation and determination of R-(-)- and S-(+)-baclofen in human plasma by high-performance liquid chromatography.
The method presented here is a high-performance liquid chromatography (HPLC)-UV detection method for the determination of baclofen R-(-)- and S-(+)-enantiomers in human plasma using a chiral separation technique. Baclofen enantiomers were extracted from human plasma with a reversed-phase solid-phase extraction (SPE) cartridge. The extract was then injected onto a HPLC system with a UV detection system set at 220 nm. The separation was achieved by using a 150x4.6 mm, 5 microm Phenomenex chirex 3216 chiral column with a mobile phase consisting of 0.4 mM CuSO(4) in acetonitrile-20 mM sodium acetate (17:83). The calibration curves were linear for both R-(-)- and S-(+)-enantiomers of baclofen in the concentration range of 20-5000 ng/ml. The average regressions were 0.9980 and 0.9991 for R-(-)- and S-(+)-baclofen, respectively. Inter-day precision was 3.3-5.2% for R-(-)-baclofen and 3.5-3.9% for S-(+)-baclofen at a concentration range of 60-4000 ng/ml. Intra-day precisions were 0.6-4.4 and 0.5-3.5% for R-(-)-baclofen and S-(+)-baclofen, respectively. The average extraction recovery was 81.6% for R-(-)-baclofen, 83.0% for S-(+)-baclofen and 94.0% for the internal standard (p-aminobenzoic acid). The limit of quantitation for both R-(-)- and S-(+)-baclofen in human plasma was 20 ng/ml. The method is simple and easy to operate with accuracy and reproducibility and it is suitable for pharmacokinetic studies.
Zhu
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Z
Pharmascience, 6111 Royalmount Avenue, Montreal, Quebec H4P 2T4, Canada. zzhu@pharmascience.com
Neirinck
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D001418:Baclofen / Q000097:blood* / Q000302:isolation & purification; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D018755:GABA Agonists / Q000097:blood* / Q000302:isolation & purification; D006801:Humans; D007202:Indicators and Reagents; D012015:Reference Standards; D013048:Specimen Handling; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
D018755:GABA Agonists; D007202:Indicators and Reagents; D001418:Baclofen