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Edetate Calcium Disodium
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C10H12CaN2Na2O8·xH2O (anhydrous) 374.27

Calciate(2-), [[N,N¢-1,2-ethanediylbis[N-(carboxymethyl)glycinato]](4-)-N,N¢,O,O¢,ON,ON¢]-, disodium, hydrate, (OC-6-21)-.
Disodium[(ethylenedinitrilo)tetraacetato]calciate(2-)hydrate [23411-34-9].

Anhydrous [62-33-9].
» Edetate Calcium Disodium is a mixture of the dihydrate and trihydrate of calcium disodium ethylenediaminetetraacetate (predominantly the dihydrate). It contains not less than 97.0 percent and not more than 102.0 percent of C10H12CaN2Na2O8, calculated on the anhydrous basis.
Packaging and storage— Preserve in tight containers.
Identification—
B: A solution (1 in 20) responds to the oxalate test for Calcium 191 and to the flame test for Sodium 191.
C: To 5 mL of water add 2 drops of ammonium thiocyanate TS and 2 drops of ferric chloride TS. To the deep red solution add about 50 mg of Edetate Calcium Disodium, and mix: the deep red color disappears.
pH 791: between 6.5 and 8.0, in a solution (1 in 5).
Water, Method I 921: not more than 13.0%.
Heavy metals, Method II 231: 0.002%.
Limit of nitrilotriacetic acid—
Mobile phase, Cupric nitrate solution, Stock standard solution, and Chromatographic system— Prepare as directed in the test for Limit of nitrilotriacetic acid under Edetate Disodium.
Resolution solution— Using Edetate Calcium Disodium instead of Edetate Disodium, prepare as directed for Resolution solution in the test for Limit of nitrilotriacetic acid under Edetate Disodium.
Standard preparation— Transfer 1.0 g of Edetate Calcium Disodium to a 100-mL volumetric flask, add 100 µL of Stock standard solution, dilute with Cupric nitrate solution to volume, and mix. Sonicate, if necessary, to achieve complete solution.
Test preparation— Transfer 1.0 g of Edetate Calcium Disodium to a 100-mL volumetric flask, dilute with Cupric nitrate solution to volume, and mix. Sonicate, if necessary, to achieve complete solution.
Procedure— Proceed as directed for Procedure in the test for Limit of nitrilotriacetic acid under Edetate Disodium: the response of the nitrilotriacetic acid peak of the Test preparation does not exceed the difference between the nitrilotriacetic acid peak responses obtained from the Standard preparation and the Test preparation (0.1%).
Magnesium-chelating substances— Weigh accurately 1.0 g, transfer to a small beaker, and dissolve in 5 mL of water. Add 5 mL of ammonia-ammonium chloride buffer TS. Then to the buffered solution add 5 drops of eriochrome black TS, and titrate with 0.10 M magnesium acetate to the appearance of a deep wine-red color: not more than 2.0 mL is required.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay— Weigh accurately about 1.2 g of Edetate Calcium Disodium, transfer to a 250-mL beaker, and dissolve in 75 mL of water. Add 25 mL of 1 N acetic acid and 1 mL of diphenylcarbazone TS, and titrate slowly with 0.1 M mercuric nitrate VS to the appearance of the first purplish color. Perform a blank determination, and make any necessary correction. Each mL of 0.1 M mercuric nitrate is equivalent to 37.43 mg of C10H12CaN2Na2O8.
Auxiliary Information— Staff Liaison : Elena Gonikberg, Ph.D., Scientist
Expert Committee : (MDGRE05) Monograph Development-Gastrointestinal Renal and Endocrine
USP29–NF24 Page 779
Pharmacopeial Forum : Volume No. 29(5) Page 1474
Phone Number : 1-301-816-8251