[Effect of temperature, daunorubicin concentration and suspension hematocrit on daunorubicin binding by human erythrocytes].

When incubated in the isotonic medium containing daunorubicin, human erythrocytes bound daunorubicin. At the initial concentration of daunorubicin in the medium of not higher than 1 mg/ml, the suspension hematocrit of about 30 per cent and the temperature of 25 degrees C the maximum binding of daunorubicin was achieved in approximately 30 minutes and was equal to about 80 per cent of the initial content. When the temperature was lowered from 30 to 15 degrees C the initial rate of the daunorubicin binding by the erythrocytes decreased several times. The increase in the initial concentration of daunorubicin in the medium from 1 to 5 mg/ml resulted in an increase in the absolute value of the initial rate of the daunorubicin binding by the erythrocytes. However, the relative rate of the binding decreased. By varying the value of the suspension hematocrit it is possible to provide either a more complete binding of daunorubicin (at higher hematocrit values) or rapid increasing of the daunorubicin concentration in the erythrocytes (at lower hematocrit values). When the erythrocytes were incubated in the presence of daunorubicin there was observed a marked leakage of hemoglobin from them (up to several per cent). The hemoglobin leakage increased with an increase in the temperature and daunorubicin concentration.