Interaction between Ferastral and plasma factors.

Ferastral, iron-poly (sorbitol-gluconic acid) complex, in aqueous solution is completely adsorbed by magnesium carbonate; Ferastral in serum solution is only partially adsorbed by magnesium carbonate. Adsorption by magnesium carbonate removes the fraction of Ferastral in serum solution which donates iron more readily to transferrin. It is suggested that this fraction comprises the smaller molecular species of the Ferastral complex and that these species have a faster rate of absorption from an intramuscular injection site than the larger molecular species of the iron complex preparation. These findings shed some light on the patterns of serum transferrin bound iron compared with serum Ferastral concentrations which occur with time after intramuscular Ferastral injection.