Pharmaceutisch Weekblad

, Volume 6, Issue 6, pp 245–248 | Cite as

Complex stability of ferrous ascorbate in aqueous solution and its significance for iron absorption

  • C. M. Plug
  • D. Dekker
  • A. Bult
Short Communications


The greater absorption of ironin vivo from ferrous ascorbate [Fe(HL)2] as compared with ferrous sulfate has been ascribed both to retardation or prevention of Fe(II) oxidation by ascorbate and to the existence of Fe(II) as a chelate with ascorbate. The available literature and our own results demonstrate that Fe(HL)2 dissociates in aqueous solution into a monomeric cationic species Fe(HL)1+, Fe2+ and HL. The HL anion acts as a monodentate. The low stability constant KFc(HL)., about 20 l.mol-s-1 at Μ = 0 and 25‡C, results in the conclusion that Fe(HL)2 is almost completely dissociated into Fe2+ and HL/s- at about pH = 5, so (chelate) complex formation does not contribute significantly to the increased iron absorption. Between pH = 6 and pH = 8 a solubility enhancing effect of ascorbate is observed which may be of relevance for the iron absorption from ferrous ascorbate.


Public Health Iron Sulfate Aqueous Solution Internal Medicine 
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Copyright information

© Royal Dutch Association for Advancement of Pharmacy 1984

Authors and Affiliations

  • C. M. Plug
    • 1
  • D. Dekker
    • 2
  • A. Bult
    • 3
  1. 1.Department of Pharmaceutical Analysis and Analytical Chemistry, Subfaculty of PharmacyState University of LeidenRA LeidenThe Netherlands
  2. 2.Servier Nederland BVNN ZoetermeerThe Netherlands
  3. 3.Department of Chemical Pharmacy, Subfaculty of PharmacyState University of UtrechtGH UtrechtThe Netherlands

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