<%@ CODEPAGE=65001 %> <%Response.Charset="UTF-8"%> Citric Acid
Citric Acid
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C6H8O7 192.12

1,2,3-Propanetricarboxylic acid, 2-hydroxy-.
Citric acid [77-92-9].

Monohydrate 210.14 [5949-29-1].
» Citric Acid is anhydrous or contains one molecule of water of hydration. It contains not less than 99.5 percent and not more than 100.5 percent of C6H8O7, calculated on the anhydrous basis.
Packaging and storage— Preserve in tight containers.
Labeling— Label it to indicate whether it is anhydrous or hydrous.
Identification— A solution responds to the tests for Citrate á191ñ.
Water, Method I á921ñ: not more than 0.5% (anhydrous form) and not more than 8.8% (hydrous form).
Readily carbonizable substances— Transfer 1.0 g, powdered for the test, to a 22- × 175-mm test tube previously rinsed with 10 mL of sulfuric acid TS and allowed to drain for 10 minutes. Add 10 mL of sulfuric acid TS, agitate until solution is complete, and immerse in a water bath at 90 ± 1 for 60 ± 0.5 minutes, keeping the level of the acid below the level of the water during the entire period. Cool the tube in running water, and transfer the acid to a color-comparison tube: the color of the acid is not darker than that of a similar volume of Matching Fluid K (see Color and Achromicity á631ñ) in a matching tube, the tubes being observed vertically against a white background.
Residue on ignition á281ñ: not more than 0.05%.
Sulfate— To 10 mL of a solution (1 in 100) add 1 mL of barium chloride TS to which has been added 1 drop of hydrochloric acid: no turbidity is produced.
Limit of oxalate— Neutralize 10 mL of a solution (1 in 10) with 6 N ammonium hydroxide, add 5 drops of 3 N hydrochloric acid, cool, and add 2 mL of calcium chloride TS: no turbidity is produced.
Organic volatile impurities, Method IV á467ñ: meets the requirements.
Assay— Place about 3 g of Citric Acid in a tared flask, and weigh accurately. Dissolve in 40 mL of water, add phenolphthalein TS, and titrate with 1 N sodium hydroxide VS. Each mL of 1 N sodium hydroxide is equivalent to 64.04 mg of C6H8O7.USP28
Auxiliary Information— Staff Liaison : Catherine Sheehan, B.Sc., Scientist
Expert Committee : (EMC) Excipients: Monograph Content
USP28–NF23 Page 483
Pharmacopeial Forum : Volume No. 30(2) Page 677
Phone Number : 1-301-816-8262