Analysis of tofisopam in human serum by column-switching semi-micro high-performance liquid chromatography and evaluation of tofisopam bioequivalency.

Soo Kyoung Baek, Sung Jin Choi, Jeong Soo Kim, Eun Jeon Park, Dong Hwan Sohn, Hee-Yong Lee, Hye Suk Lee

Index: Biomed. Chromatogr. 16(4) , 277-81, (2002)

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Abstract

A rapid and sensitive column-switching semi-micro HPLC method is described for the direct analysis of tofisopam in human serum. The sample (100 microL) was directly injected onto the precolumn (Capcell Pak MF Ph-1), where unretained proteins were eluted to waste. Tofisopam was then eluted into an enrichment column using 13% acetonitrile in 50 mM phosphate buffer (pH 7.0) containing 5 mM sodium octanesulfonate and subsequently into the analytical column using 43% acetonitrile in 0.1% phosphoric acid containing 5 mM sodium octanesulfonate. The detection limit (2 ng/mL), good precision (CV < or = 4.2%) and speed (total analysis time 24 min) of the present method were sufficient for drug monitoring. This method was successfully applied to a bioequivalence test of two commercial tofisopam tablets.Copyright 2002 John Wiley & Sons, Ltd.