Chemical reactions of vitamin C with intravenous-iron formulations.
BACKGROUND
Intravenous (IV) iron is widely prescribed for patients on haemodialysis, to replace iron losses during treatment. It releases labile iron, which can induce oxidation of vitamin C and trigger oxidant damage. We examined the stability of vitamin C in the presence of IV iron compounds. We further examined in the ability of vitamin C to release iron from these compounds.


METHODS
Vitamin C was measured by high-performance liquid chromatography with electrochemical detection. Iron release from iron sucrose (FeSuc) and ferric gluconate (FeGlu) was determined with the ferrozine method.


RESULTS
Vitamin C, in human plasma or fetal calf serum, was oxidized in this order of reactivity: FeSuc > FeGlu > blank reaction. FeSuc and FeGlu also oxidized vitamin C when added to freshly obtained whole human blood. During a 4 h incubation in buffer, vitamin C stimulated the release of 60% of the iron content of FeSuc at p 4, with lesser amounts at pH 3, 5 and 6, and 5% release at pH 7. Vitamin C also triggered the release of iron from FeGlu, but less release was observed than with FeSuc. Using ferrozine reagent, no iron release was detected to heparinized human plasma, following addition of 500 microM concentrations of iron compounds.


CONCLUSIONS
Each IV-iron compound can oxidize substantial amounts of vitamin C when added to plasma or whole blood. The interaction of vitamin C is accompanied by release of iron from the particle at mildly acidic pH, which may explain the ability of high-dose vitamin C to mobilize iron from storage sites for erythropoiesis.
Wang
Suxin
S
Department of Health and Clinical Science, University of Massachusetts, Lowell, MA, USA.
Geraci
Gina
G
Kuhlmann
Martin K
MK
Levin
Nathan W
NW
Handelman
Garry J
GJ
D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism* / Q000494:pharmacology*; D002417:Cattle; D004347:Drug Interactions; D005290:Ferric Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D000077605:Ferric Oxide, Saccharated; D005937:Glucaric Acid; D006801:Humans; D007275:Injections, Intravenous
D005290:Ferric Compounds; D000077605:Ferric Oxide, Saccharated; D001205:Ascorbic Acid; D005937:Glucaric Acid; C035552:ferric gluconate