Interaction of anthracycline drugs with canine and bovine carrier erythrocytes.

Daunomycin interacts with canine and bovine erythrocytes making them permeable to [14C]sucrose, a nonpermeant. The drug causes the red blood cell (RBC) to swell and form an echinocyte-stomatocyte cell type. Defects in the RBC membrane were observed for murine RBC as well. Thus, daunomycin interacts with RBC such that its deleterious action would not make this drug a promising candidate for encapsulation in carrier erythrocytes. Contrary to previous reports, daunomycin easily permeates murine RBC and avidly binds to the cells; as much as 70% of the drug remains associated with normal murine RBC. Several different approaches were taken to unequivocally establish that daunomycin does not entrap in canine RBC in a classical manner. The extent of interaction of the drug with RBC does not appear to be RBC specific because similar results were obtained with canine, bovine, and murine RBC.