Mean net iron excretion in C apella monkeys with iron overload (see text) after administration of DFO by SC injection and of HBED by SC injection. Excretion is shown as μg Fe/kg body weight on the scale of the left vertical axis and as efficiency of chelation (net iron excretion/total iron-binding capacity of chelator administered, expressed as a percent) on the right vertical axis. Both chelators were given at a dose of 150 μmol/kg body weight. For convenience, the result of our previously published study31of the oral administration of HBED in phosphate buffer to C apella monkeys with a similar magnitude of iron overload is also shown; this previous result is indicated by an asterisk.