Edetic acid calcium, disodium salt

Synonyms calcium disodium edetate calcium disodium ethylenediaminetetraacetate calcium disodium (ethylene-dinitrilo)tetraacetate E385 edathamil calcium disodium edetic acid calcium disodium salt EDTA calcium ethylene-diaminetetraacetic acid calcium disodium chelate [(ethyl-enedinitrilo)tetraacetato]calciate(2-) disodium sodium calciumedetate Nersene CA. 

Edetic acid calcium disodium salt. See Calcium disodium EDTA... 

Edetic acid and edetate salts are used in pharmaceutical formulations, cosmetics, and foods as chelating agents. They form stable water-soluble complexes (chelates) with alkaline earth and heavy metal ions. The chelated form has few of the properties of the free ion, and for this reason chelating agents are often described as removing ions from solution this process is also called sequestering. The stability of the metal-edetate complex depends on the metal ion involved and also on the pH. The calcium chelate is relatively weak and will preferentially chelate heavy metals, such as iron, copper, and lead, with the release of calcium ions. For this reason, edetate calcium disodium is used therapeutically in cases of lead poisoning see also Section 18. 

Although edetic acid is fairly stable in the solid state, edetate salts are more stable than the free acid, which decarboxylates if heated above 150°C. Disodium edetate dihydrate loses water of crystallization when heated to 120°C. Edetate calcium disodium is slightly hygroscopic and should be protected from moisture. 

Other salts of edetic acid that are commercially available include diammonium, dimagnesium, ferric sodium, and magnesium disodium edetates. Therapeutically, a dose of 50mg/kg body-weight of disodium edetate, as a slow infusion over a 24-hour period, with a maximum daily dose of 3 g, has been used as a treatment for hypercalcemia. For the treatment of lead poisoning, a dose of 60-80 mg/kg of edetate calcium disodium, as a slow infusion in two daily doses, for 5 days, has been used. 

Note A number of salts of EDTA are available with uses identical or similar to the acid. The USP salts are called edetates (calcium disodium, disodium edetates) others are usually abbreviated to EDTA (tetrasodium, trisodium EDTA). Other salts, known chiefly under trademark names, are the sodium ferric, dihydrogen ferrous and arange of disodium salts with magnesium, divalent cobalt, manganese, copper, zinc, and nickel. 

Ethylenediaminetetraacetic acid (EDTA) is a polycarboxylic acid chelator its sodium salt (edetate disodium, Na EDTA), and a number of closely related compounds chelate many divalent and triva-lent metals. The cation used to make a water-soluble salt of EDTA has an important role in the toxicity of the chelator. Na EDTA causes hypocalcemic tetany. However, edetate calcium disodium (CaNa EDTA) can be used for treatment of poisoning by metals that have higher affinity for the chelating agent than does Ca +. 

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