On-line Trace Enrichment in High Performance Liquid Chromatography Using XAD-2 Precolumn for the Determination of Lonazolac in Human Plasma

A new column-switching high performance liquid chromatographic method was developed for the determination of lonazolac in plasma. This method was based on the on-line trace enrichment of lonazolac using a precolumn packed with Amberlite XAD-2. The analysis was complete in 20 min. between injections and the limit of detection was $0.1{\mu}g/ml$ using $100{\mu}l$ of plasma. The method was linear in range of $0.1-10{\mu}g/ml$ with a correlation coefficient of 0.9991. Absolute recovery of lonazolac from the spiked plasma samples ranged from 95.6% to 97.1%. The method was shown to be reproducible over the concentration range studied.