Separation of etoposide phosphate and methotrexate by capillary zone electrophoresis using UV detection with a high sensitivity cell

Etoposide phosphate and methotrexate are important anti-tumor chemotherapeu tic agents. Our previously presented capillary zone electrophoresis (CZE) m ethod using a high sensitivity cell (Z-cell) for quantitative analysis in b iological media (urine, plasma) showed good precision and accuracy. The pre sent results show that the investigation using a capillary with high sensit ivity cell led to an approximately 10-fold improvement of the detection lim it compared to standard capillaries. Plasma and urine samples were analyzed by using a calibration curve for drug concentrations between 0.1 and 100 m u g/mL. Good detection Limits and good relative standard deviations of the migration times and of the peak areas were observed in these experiments.