HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF IRINOTECAN (CPT-11) AND ITS ACTIVE METABOLITE (SN-38) IN HUMAN PLASMA

A simplified method for the simultaneous determination of irinotecan ( CPT-11, I) and its active metabolite (SN-38, II) in human plasma by hi gh-performance liquid chromatography (HPLC) with fluorescence detectio n has been developed. Following the addition of the internal standard (I.S.) camptothecin, the drugs were extracted from plasma using methan ol. The average extraction efficiencies were 87% for I, 90% for II and 90% for the I.S. Chromatography was performed using a TSK gel ODS-80T s column, monitored at 556 nm (excitation wavelength, 380 nm) and the mobile phase was acetonitrile-50 mM disodium hydrogen phosphate (28:72 ) containing 5 mM heptanesulphonate (pH 3.0). The linear quantitation ranges for I and II were 30-2000 and 1-30 ng/ml, respectively.