Factors influencing the formation of methemoglobin in desferrioxamine loaded erythrocytes.

Desferrioxamine (DFO) in therapeutically useful amounts was incorporated into red blood cells (RBC) by means of a dialysis method. Entrapped DFO interacted with hemoglobin which was indicated by the formation of methemoglobin. This process was influenced to a great extent by the duration and temperature of the incubation steps. In contrast to added methylene blue the co-entrapment of ascorbic acid proved to be a very effective measure for protecting hemoglobin from oxidation and maintaining intracellular 2,3-diphosphoglycerate (2,3-DPG). Hypernormal values of 2,3-DPG could be obtained by the incubation in solutions containing phosphate, inosine, and pyruvate. Loaded RBC prepared in such a way should be characterized by a nearly normal oxygen-transport function and survival in vivo.