Trace Elements in Medicine (Moscow)
18(3): 42-48
ORIGINAL PAPER

RATIONALE FOR MEDICAL APPLICATION OF POLYURONATES OF BIOGENIC METALS AS CATION EXCHANGE RESIN

N.Sh. Kajsheva, A.Sh. Kajshev

Pyatigorsk Medico-Pharmaceutical Institute, Kalinin ave., 11, Pyatigorsk, 357532, Stavropol region, Russia

DOI: 10.19112/2413-6174-2017-18-3-42-48 

ABSTRACT. Constants of exchange of polyuronates (pektinates, alginates, polyguluronates, polymannuronates) of Na, K, Mg, Ca on ions of other metals either biogenous (Mg2+, Ca2+) or toxic (Sr2+, B2+, Pb2+, Cd2+, Cu2+, Co2+) were studied. Metal ion exchange efficiency in pectinate depends on radius of metal ions bound and the presence of deacetylated hydroxyl groups in pectins. The pectinates K and Na are highly selective to the Ba2+ ion with the greatest radius (0.135 nm), in contrast to Ca and Mg pectinates. The same situation exists with respect to the Sr2+ ion (0.113 nm). Almost all pectinates are highly selective to the Pb2+ ion (0.121 nm): K, Na, Mg. To the Cd2+ ion (0.097 nm) high selectivity is exhibited by Na pectinate, to the Co2+ ion (0.072 nm) – by K pectinate (13.29), to the Cu2+ ion (0.069 nm) – by pectinates of K and Ca. From the viewpoint of binding the biogenic metal Mg2+ (0.065 nm), Na pectinate is a safe one, unlike K pectinate. In relation to another biogenic metal Ca2+ (0.099 nm), Mg (0.71) and Na pectinates are safe, in contrast to the K pectinate. Compared with pectinates, alginates exhibit lower selectivity to Ba2+, Sr2+, Pb2+, Cd2+, Cu2+ and Co2+ ions. How-ever, unlike pectinates, alginates less dangerous with respect to ions of biogenic metals: Ca2+, Mg2+. Structural blocks of alginates in varying degrees show selectivity for metal ions. Polyguluronates are more selec-tive than polymannuronates to Ba2+, Sr2+, Cu2+ ions. This pattern is not characteristic with respect to the Co2+ ion. Selec-tivity of polyguluronates to Sr2+ ions exceeds that of pectinates and alginates, while to other ions it is comparable or lower as compared with alginates. However, in contrast to all obtained polyuronates, polyguluronates are the most se-lective to the Ca2+ ion. The obtained results are the justification for a differentiated selection of polyuronates as the drugs that promote binding of toxic metals without upsetting the balance of essential mineral elements in biological tissues and fluids.

KEYWORDS: polyuronates, pectinates, alginates, polyguluronate, polymannuronate, biogenic metals, toxic met-als, constants of exchange.