HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC QUANTITATION OF TOTAL AND LACTONE 20(S)CAMPTOTHECIN IN PATIENTS RECEIVING ORAL 20(S)CAMPTOTHECIN

We have developed a sensitive high-performance liquid chromatography ( HPLC) assay to quantitate total and lactone forms of 20(S)camptothecin (CPT) in human plasma. Lactone and total CPT were extracted using sol id-phase extraction and liquid-liquid extraction, respectively. The ex tracted lactone samples could be stored without immediate HPLC analysi s. The two forms of CPT were quantitated by reversed-phase HPLC with f luorescence detection. The extraction efficiencies were about 100% and 92% for the total and lactone forms, respectively. The lower limit of quantitation was 5.74 nM for the two forms. The method was reproducib le with a mean interday and intraday variability of 6% for total CPT a nd 4% and 6%, respectively, for lactone CPT. The assay could effective ly quantitate lactone and total CPT in patients receiving single dose and multiple doses of oral CPT. (C) 1998 Elsevier Science B.V.