ABSTRACT. The search for new antidotes that effectively bind toxic metals and preserve the content of biogenic metals is a pressing issue in pharmacy. The known groups of detoxifying drugs do not meet the above requirements: complexones, antidotes containing sulfhydryl groups that, by forming strong compounds with metals and their radioactive isotopes, lead to the removal of trace elements from cell enzymes, and, consequently, to hematopoiesis, a decrease in the content of hemoglobin, Fe, vitamin B12, and the mobilization of Ca from bone tissue. High sorption activity is also characteristic of adsorbents with non-specific detoxifying action, but their action, which manifests itself only in the gastrointestinal tract, leads to a violation of the absorption of Ca, Fe, vitamins, hormones, lipids, and proteins. Acid polysaccharides (polyuronides) – alginates (Alg) and pectins (Pec) – seem to be promising antidotes. They have the following advantages: they are biologically available (accumulate in various biological tissues, including bone tissue); they enhance the antitoxic function of the liver by increasing the activity of monooxygenases; they slow down lipid peroxidation reactions and activate cell defense mechanisms, restoring the activity of tissue respiration enzymes (catalase, peroxidase).
The purpose of the study: to determine the composition and stability of soluble products of interaction of NaAlg and Pec with ions of toxic (Pb(II), Cu(II)) and biogenic (Mn(II)) metals to substantiate the possibility of using polyuronides as antidotes.
Materials and methods. The method of curve intersection was used as a calculation method, and the method of analysis was complexometry.
Results. Formation of products of various compositions (in terms of polyuronide monomer) in solution was established: PbAlg2, PbAlg3, PbPec2, CuAlg, CuPec, MnAlg, MnPec, which indicates stepwise complex formation. Polyuronides significantly preferentially bind Pb(II) compared to Cu(II) (3-5 orders of magnitude more stable), Mn(II) (11-31 orders of magnitude more stable). Metal complexes of polyuronides are significantly less stable (4-24 orders of magnitude) than biological complexes (amino acids, nucleotides, enzymes) with the same metals, therefore polyuronides cannot destroy biological complexes.
Conclusion. Relatively high efficiency of binding Alg and Pec ions of toxic metals with low selectivity to biogenic metals with other effects of polyuronides determine the advantages of polyuronides as antidotes compared to known detoxicants.
KEYWORDS: alginates, pectinates, metal (II) ions, composition of complexes, stability of complexes.
For citation: Kaisheva N.Sh. Study of the composition and stability of soluble metal (II) polyuronates by the curve intersection method. Trace elemets in medicine. 2025;26(3):45−59. DOI: 10.19112/2413-6174-2025-26-3-45-59
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Information about the author:
N.Sh. Kaisheva – Dr.Sc. (Pharm.), Professor, Professor of the Department of Pharmaceutical Chemistry
E-mail: caisheva2010@yandex.ru; ORCID: 0000-0002-1277-0825; SPIN 6389-6826