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Potassium Bitartrate
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C4H5KO6 188.18

Butanedioic acid 2,3-dihydroxy-, [R-(R*,R*)]-, monopotassium salt.
Potassium hydrogen tartrate [868-14-4].
» Potassium Bitartrate, dried at 105 for 3 hours, contains not less than 99.0 percent and not more than 101.0 percent of C4H5KO6.
Packaging and storage— Preserve in tight containers.
Identification—
A: Ignite it: it leaves a residue that imparts a reddish purple color to a nonluminous flame.
B: A saturated solution of it yields a yellowish orange precipitate with sodium cobaltinitrite TS.
C: A solution (1 in 10) responds to the tests for Tartrate 191.
Insoluble matter— Mix 500 mg of it with 3 mL of 6 N ammonium hydroxide: no undissolved residue remains.
Ammonia— Heat 500 mg of it with 5 mL of 1 N sodium hydroxide: no ammonia odor is detected.
Heavy metals, Method I 231— Mix 2 g of it with 15 mL of water, and add 6 N ammonium hydroxide dropwise until solution is complete. Add 1 drop of phenolphthalein TS, and add just sufficient 1 N acetic acid dropwise to discharge the pink color. Add 2 mL of 1 N acetic acid, and dilute with water to 25 mL: the limit is 0.002%.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay— Dry about 6 g of Potassium Bitartrate at 105 for 3 hours, allow to cool, and weigh accurately. Dissolve in 100 mL of boiling water, add a few drops of phenolphthalein TS, and titrate with 1 N sodium hydroxide VS to a pink endpoint. Perform a blank determination, and make any necessary correction. Each mL of 1 N sodium hydroxide is equivalent to 188.2 mg of C4H5KO6.
Auxiliary Information— Staff Liaison : Elena Gonikberg, Ph.D., Scientist
Expert Committee : (MDGRE05) Monograph Development-Gastrointestinal Renal and Endocrine
USP29–NF24 Page 1758
Pharmacopeial Forum : Volume No. 31(3) Page 786
Phone Number : 1-301-816-8251