A fluorimetric, column-switching HPLC and its application to an elimination study of LLU-alpha enantiomers in rat plasma

A method for the enantiomeric determination of 2,7,8-trimethyl-2-(beta -car boxyethyl)-6-hydroxy chroman (LLU-alpha, gamma -CEHC) in rat plasma was dev eloped using high-performance liquid chromatography (HPLC) with a fluorimet ric derivatization with 4-N, N-dimethylaminosulfonyl-7-piperazino-2,1,3-ben zoxadiazole (DBD-PZ) followed by O-acetylation with acetyl chloride. The pr oposed HPLC system used two non-chiral columns (phenyl and octadecylsilica) and a chiral column ja modified cellulose type), which were connected via two column-switching valves. A derivatized sample prepared from rat plasma was first separated on the phenyl column, and the fraction including LLU-a derivative was introduced to the octadecylsilica column to quantify the con centration of the mixture of S- and R-LLU-alpha. Finally, the LLU-alpha der ivative was directly injected into the chiral column to obtain the ratio of the enantiomers. The proposed HPLC system was applied to the enantiomeric determination of LLU-alpha in plasma after intravenous administration of ra cemic LLU-alpha. S-LLU-alpha was eliminated faster than R-LLU-alpha, and it s concentration in plasma decreased to one-third at 2 min after dosing. Cop yright (C) 2001 John Wiley & Sons, Ltd.