Ferrofer Mechanism of Action

The polynuclear iron (III)-hydroxide cores are superficially surrounded by a large number of non-covalently bound sucrose molecules resulting in a complex whose molecular mass is approximately molecular weight 43 kD. This is sufficiently large to prohibit renal elimination. The resulting complex is stable and does not release ionic iron under physiological conditions. The iron in the polynuclear cores is bound in a similar structure as in the case of physiologically occurring ferritin.
Administration of iron sucrose causes physiological changes which involve the uptake of iron. Iron sucrose possesses a low toxicity with LD₅₀ of >200 mg Fe/kg body weight when administered to mice. It has a therapeutic index of about 30 (200/7).
Pharmacokinetics: The pharmacokinetics of iron (III)-hydroxide sucrose complex was investigated after IV injection of a single dose containing 100 mg Fe (III) in healthy volunteers. The maximum iron levels, averaging 538 micromol/L, are obtained 10 min after injection. The volume of distribution of the central compartment corresponds in good agreement to the volume of serum (approximately 3 L).
The iron injected is quickly cleared from the serum, the terminal t_½ is approximately 6 hrs. The volume of distribution at steady-state is about 8 L, which indicates a low iron distribution in the body water. Due to the lower stability of iron (III)-hydroxide sucrose complex in comparison to transferrin, a competitive exchange of iron to transferrin was observed. This results in an iron transport of approximately 31 mg Fe (III)/ 24 hrs.
Renal elimination of iron, occurring in the first 4 hrs after injection, corresponds to <5% of the total body clearance (approximately 20 mL/min). After 24 hrs, the serum levels of iron are reduced to the predose iron levels and about 75% of the dosage of sucrose is excreted.