Skip to main content
SpringerLink
Log in

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

  • Short Communications
  • Published:
Pharmaceutisch Weekblad Aims and scope Submit manuscript

Abstract

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.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

References

  1. Marx JJM, Stiekema J. Mucosal uptake, mucosal transfer and retention of a therapeutic dose of iron. Eur J Clin Pharmacol 1982;23:335–8.

    Article  PubMed  Google Scholar 

  2. Goodman Gilman A, Goodman LS, Gilman A. The Pharmacological Basis of Therapeutics. 6th ed. New York: MacMillan Co., 1980:1314–22.

    Google Scholar 

  3. Cox TM, O'Donnell MW. Studies on the binding of iron by rabbit intestinal microvillus membranes. Biochem J 1981;194:753–9.

    PubMed  Google Scholar 

  4. Hungerford DM, Linder MC. Interactions of pH and ascorbate in intestinal iron absorption. J Nutr 1983;113:2615–22.

    PubMed  Google Scholar 

  5. Hearn RA, Bugg CE. Calcium binding to carbohydrates: crystal structure of calcium ascorbate dihydrate. Acta Cryst 1974;B30:2705–11.

    Google Scholar 

  6. Ulmgren P, Wahlberg O. Equilibrium studies of lascorbate ions. ix. Equilibria between iron(11) ions, ascorbate ions, and protons in 3M NaClO4 medium. Acta Chem Scand 1974;A28:631–7.

    Google Scholar 

  7. Al-Meshal IA, Hassan MMA. Ascorbic Acid. In: Florey K, red. Analytical Profiles of Drug Substances, Vol 11. Washington: The American Pharmaceutical Association, 1982:45–78.

    Google Scholar 

  8. Kriss EE. Structure of ascorbato-complexes of metals. Russ J Inorg Chem 1978;23:1004–7.

    Google Scholar 

  9. Kurbatova GT, Kriss EE, Alekseev Yu E, Sudareva TP. Comparison of the complex-forming properties of ascorbic and 5,6-00′-isopropylidene ascorbic acids in aqueous and aqueous-organic solutions. Russ J Inorg Chem 1980;25:1503–5.

    Google Scholar 

  10. Dubey KP, Parveen S. Ascorbate-M(11) systems — Equilibrium studies. Curr Sci 1978;47:415–6.

    Google Scholar 

  11. Holzbecher Z, Divis L, Kral M, Sucha L, Vlacil F. Handbook of Organic Reagents in Inorganic Analysis. Chichester: Ellis Horwood Ltd., 1976:76–8.

    Google Scholar 

  12. Kurbatova GT, Kriss EE, Alekseev Yu E, Tyumenev VA. Preparation and study of vanadium(iv) and iron(II) ascorbates. Russ J Inorg Chem 1979;24:1047–50.

    Google Scholar 

  13. Laurence GS, Ellis KJ. The detection of a complex intermediate in the oxidation of ascorbic acid by ferric ion. J Chem Soc [Dalton] 1972; 1667–70.

  14. Martinez P, Uribe D. Study of the complexes of the ascorbic acid-iron(III) system. Z Naturforsch 1982;37b:1446–9.

    Google Scholar 

  15. Bult A. Ion-pair and Metal Complex Formation in Drug Analysis. In: Breimer DD, Speiser P, red. Topics in Pharmaceutical Sciences 1983. Amsterdam: Elsevier Science Publishers BV, 1983:3–14.

    Google Scholar 

  16. Conrad ME, Schade SG. Ascorbic acid chelates in iron absorption: a role for hydrochloric acid. Gastroenterology 1968;55:35–45.

    PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Pharmaceutical Analysis and Analytical Chemistry, Subfaculty of Pharmacy, State University of Leiden, P.O. Box 9502, 2300, RA Leiden, The Netherlands

    C. M. Plug

  2. Servier Nederland BV, Storkstraat 5, 2722, NN Zoetermeer, The Netherlands

    D. Dekker

  3. Department of Chemical Pharmacy, Subfaculty of Pharmacy, State University of Utrecht, Catharijnesingel 60, 3511, GH Utrecht, The Netherlands

    A. Bult

Authors
  1. C. M. Plug
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. D. Dekker
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. A. Bult
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Plug, C.M., Dekker, D. & Bult, A. Complex stability of ferrous ascorbate in aqueous solution and its significance for iron absorption. Pharmaceutisch Weekblad Scientific Edition 6, 245–248 (1984). https://doi.org/10.1007/BF01954553

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF01954553

Keywords

Search

Navigation