Intracellular measurement of anthracyclines with flow cytometry

: The intracellular drug uptake of anthracycline antibiotics, including the anthrachinone analogue mitoxantrone, was investigated. Measurement of drug uptake for each of the white cell subpopulations is possible by Flow cytometry (FCM). Cell separation was carried out by two different methods, using Lysing solution and Ficoll. Ficoll was found to be the best for further investigations in cell kinetics. Stock solutions of each drug, ranging from 0.5-3 micrograms/ml, were incubated with cell suspensions of healthy donors. In the case of doxorubicin, daunorubicin and epirubicin a linear correlation between drug concentration in the incubation medium and intracellular drug level was found. In further studies drug concentration was constant (1 microgram/ml or 3 micrograms/ml) and the intracellular drug uptake was measured at various incubation times. Examinations were carried out with the two different cell separation methods, mentioned above. In healthy donors the reproducibility of FCM measurement was examined. In conclusions of the results observed in experiments, FCM seems to be a suitable, reproducible technique for determination of cellular anthracycline concentrations with the exclusion of aclacinomycin A and mitoxantrone because of their physical properties.