ISOCRATIC HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY OF TAXOL IN BIOLOGICAL-FLUIDS AND TISSUES USING AUTOMATED COLUMN-SWITCHING

This report describes the analysis of taxol in human plasma, cell cult ure medium, and dog bladder tissue by isocratic high-performance liqui d chromatography (HPLC) with automated column switching. Cephalomannin e was used as the internal standard. Biological samples were extracted with ethyl acetate, with a recovery of > 80%. Sample extracts reconst ituted in 37.5% acetonitrile were stable in polypropylene tubes at roo m temperature for 22 h. The HPLC stationary phase consisted of a clean -up column (Nova-Pak C-8, 75 x 3.9 mm I.D., 4 mu m particle size) and an analytical column (Bakerbond octadecyl, 250 x 4.6 mm I.D., 5 mu m p article size). Taxol and cephalomannine were monitored at 229 nm. Samp les were injected onto the clean-up column and eluted with the clean-u p mobile phase (37.5% acetonitrile in distilled water) at I ml/min. Co ncurrently, the analytical mobile phase (49% acetonitrile in distilled water) was directed through the analytical column at a flow-rate of 1 .2 ml/min. A heart-cut fraction from 8 to 15 min was transferred from the clean-up column onto the analytical column. Loading of a second sa mple onto the clean up column while the first sample was eluting from the analytical column reduced the HPLC analysis time to about 15 min p er sample. This method has a lower detection limit of 5 ng/ml and intr a- and inter-day variations of < 5%.