In vitro stability and compatibility of daunorubicin, cytarabine, and etoposide

The continuous infusion of cytarabine, daunorubicin, and etoposide offers several theoretical advantages over bolus infusion in the treatment of acute nonlymphocytic leukemia. To date, this approach has been limited by the need for three separate iv lines. The in vitro stability and compatibility of these three agents were therefore evaluated. Solutions of 200 mg of cytarabine, 25 mg of daunorubicin, and 300 mg of etoposide per 750 ml of 5% dextrose and 0.45% saline were prepared alone and in combination. The solutions were evaluated visually, spectrophotometrically, and by high-pressure liquid chromatography (HPLC) twice daily for 72 hours. Precipitates or color changes were not noted. Changes in the patterns of the spectral scans and chromatographs were not observed. Concentrations of the drugs as assessed by HPLC were stable over the 72-hour period of observation for both individual and combined drug preparations. In conclusion, cytarabine, daunorubicin, and etoposide are stable and compatible in vitro for at least 72 hours. These drugs can therefore be administered together by continuous infusion using a single iv line.