DETERMINATION OF THE CAMPTOTHECIN DERIVATIVES CPT-11 AND SN-38 IN URINE AND SALIVA BY MICELLAR ELECTROKINECTIC CHROMATOGRAPHY

The anti-cancer synthetic drug irinotecan (CPT-11) and its active metabolite SN-38 have been determined by micellar electrokinetic capillary chromatography (MEKC). The detection of the analytes was made at 368 nm and their separation took less than 7 min using a borate buffer (pH 8.8 at 25 mmol L-1) solution containing sodium dodecyl sulfate (45 mmol L-1) and acetonitrile (13.5% v/v). On-line analyte concentration (normal stacking mode) and the use of a highly sensitive cell (Z shaped cell) improved detection limits (at the 10(-8) mol L-1 level). Recovery in fortified human saliva was 108 +/- 5%, in agreement with the result achieved with the reference HPLC method. For the analysis of urine from rats submitted to a single dose of CPT-11 and SN-38, camptothecin was used as internal standard enabling recoveries close to 100% when compared to the results achieved using HPLC.