DETERMINATION OF ALPHA-TOCOPHEROL STEREOISOMERS IN BIOLOGICAL SPECIMENS USING CHIRAL PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

The alpha-tocopherol stereoisomers in biological specimens were invest igated using high-performance liquid chromatography. All-rac-alpha-Toc acetate was separated into four peaks (peak area ratio: 4:2: 1: 1) by Chiralpak OP(+) HPLC. 2R-isomers constituted the first peak and 2S-is omers were separated into three peaks (peak area ratio: 2: 1:1). 2-Amb o-alpha-Toc acetate was completely separated into RRR- and SRR-alpha-T oc acetate by this method. The present HPLC method was used for the se paration of all-rac-alpha-Toc in blood and tissues of rat. The analyti cal recoveries of RRR- and SRR-alpha-Toc acetate added to blood and ti ssues were 90.5-98.2% for RRR-alpha-Toc and 93.7-100.5% for SRR-alpha- Toc. The distribution of alpha-Toc stereoisomers in the blood and tiss ues from rats administered all-rac-alpha-Toc acetate was investigated by HPLC. The concentrations of the 2R-isomers in the blood and tissues were markedly higher than the concentrations of the 2S-isomers, and t he levels of alpha-Toc stereoisomers showed marked differences between blood and tissues.