On-line solid-phase extraction and determination of paclitaxel in human plasma

The application of coupled-column liquid chromatographic analysis to pharmacokinetic studies eliminates the need for sample clean-up from plasma. Considering lipophilic antineoplastic agents, we tested this approach to analyze paclitaxel under unfavourable circumstances (i.e., weekly low-dose regimen, plasma protein binding >90%, UV detection at 229 nm). The excellent quality control data (recovery: 95.6-100.7%, inter-assay relative standard deviation on 5 days: 1.3-3.2%, accuracy: 0.9-2.7%) and the detection limit of 19 nM indicates the usefulness of this method for the analysis of paclitaxel in plasma using on-line solid-phase extraction.