Improved method of determining thiamylal enantiomers in human serum by high-performance liquid chromatography

Thiamylal, a widely used anesthetic drug, has two enantiomers. We developed a simple and rapid method for measuring the thiamylal enantiomers in human serum. The method involves a liquid-liquid extraction procedure followed b y chiral resolution using a 5 mu m silica-bonded alpha(1)-acid glycoprotein column (Chiral-AGP). The thiamylal enantiomers and internal standard were eluted within 15 min and were well-resolved. At concentrations of 1, 5 and 20 mu g ml(-1), the relative standard deviations of R(+)- and S(-)-thiamyla l were 1.35-2.88% and 1.37-3.01%, respectively, for the intra-day assay, an d 2.93-4.46% and 2.46-4.84%, respectively, for the inter-day assay. This me thod facilitates the routine monitoring and pharmacokinetic studies of thia mylal enantiomers. (C) 1999 Elsevier Science B.V. All rights reserved.