Lithium Citrate

Lithium Citrate BP
Ph Eur
C6H5Li3O7,4H2O — 282.0 — 6080-58-6

DEFINITION
Trilithium 2-hydroxypropane-1,2,3-tricarboxylate tetrahydrate.
Content: 98.0 per cent to 102.0 per cent (anhydrous substance).

CHARACTERS
Appearance: White or almost white, fine crystalline powder.
Solubility: Freely soluble in water, slightly soluble in ethanol (96 per cent).

IDENTIFICATION
A. When moistened with hydrochloric acid, it gives a red colour to a non-luminous flame.
B. Dilute 3 ml of solution S (see Tests) to 10 ml with water. Add 3 ml of potassium ferriperiodate solution. A white or yellowish-white precipitate is formed.
C. To 1 ml of solution S add 4 ml of water. The solution gives the reaction of citrates.

TESTS
Solution S: Dissolve 10.0 g in carbon dioxide-free water prepared from distilled water and dilute to 100 ml with the same solvent.
Appearance of solution: Solution S is clear and colourless.
Acidity or alkalinity: To 10 ml of solution S add 0.1 ml of phenolphthalein solution. Not more than 0.2 ml of 0.1 M hydrochloric acid or 0.1 M sodium hydroxide is required to change the colour of the indicator.
Readily carbonisable substances: To 0.20 g of the powdered substance to be examined add 10 ml of sulphuric acid and heat in a water-bath at 90 ± 1C for 60 min. Cool rapidly. The solution is not more intensely coloured than reference.
Chlorides: Maximum 100 ppm.
Oxalates: Maximum 300 ppm, calculated as anhydrous oxalate ion.
Sulphates: Maximum 500 ppm.
Heavy metals: Maximum 10 ppm.
Water: 24.0 per cent to 27.0 per cent, determined on 0.100 g.

ASSAY: Dissolve 80.0 mg in 50 ml of anhydrous acetic acid, heating to about 50C. Allow to cool. Titrate with 0.1 M perchloric acid, using 0.25 ml of naphtholbenzein solution as indicator, until the colour changes from yellow to green.
1 ml of 0.1 M perchloric acid is equivalent to 7.00 mg of C6H5Li3O7.

STORAGE: In an airtight container .

Lithium Citrate USP
C6H5Li3O7.4H2O 281.98
1,2,3-Propanetricarboxylic acid, 2-hydroxy-trilithium salt tetrahydrate.
Trilithium citrate tetrahydrate [6080-58-6].
Anhydrous 209.93 [919-16-4].
Lithium Citrate contains not less than 98.0 percent and not more than 102.0 percent of C6H5Li3O7, calculated on the anhydrous basis.

Identification:
A: When moistened with hydrochloric acid, it imparts an intense crimson color to a nonluminous flame.
B: It responds to the test for Citrate.
pH: between 7.0 and 10.0, in a solution (1 in 20).
Water: Dry it at 150 for 3 hours: it loses between 24.0% and 28.0% of its weight.
Carbonate: Add about 0.5 g to 5 mL of 6 N acetic acid: not more than a slight effervescence is produced.
Heavy metals: the limit is 0.001%.

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