HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY FOR SEMATILIDE IN PLASMA USING SOLID-PHASE EXTRACTION MICROCOLUMN TECHNOLOGY

A simple and sensitive high-performance liquid chromatographic assay for quantification of sematilide in rabbit plasma was developed. After extraction of samples via solid-phase extraction on C-8, microcolumns, baseline resolution was achieved on a reversed-phase 5 mu m Inertsil ODS-2 column using isocratic conditions with mobile phase consisting of water-glacial acetic acid-acetonitrile-methanol-triethylamine (93.5:4.0:1.5:0.5:0.5) and UV detection at 254 nm. The assay did not require evaporation or reconstitution steps. The injection interval was 8 minutes. The inter-day coefficient of variation for replicate analysis of spiked samples was less than 7.6% and the accuracy was more than 97% over the standard curve range (0.128 to 3.191 mu M) using 0.5 mi of plasma. The assay has been successfully applied to pharmacokinetic studies in rabbits.