C4H4KNaO6·4H2O 282.22

Butanedioic acid, 2,3-dihydroxy-, [R-(R*,R*)]-, monopotassium monosodium salt, tetrahydrate.
Monopotassium monosodium tartrate tetrahydrate [6100-16-9; 6381-59-5].

Anhydrous 210.16 [304-59-6].

Packaging and storage— Preserve in tight containers.

Identification—

Alkalinity— A solution of 1.0 g in 20 mL of water is alkaline to litmus, but after the addition of 0.20 mL of 0.10 N sulfuric acid no pink color is produced by the addition of 1 drop of phenolphthalein TS.

Water, Method I 921: between 21.0% and 27.0%.

Limit of ammonia— Heat a 5-mL portion of a solution (1 in 10) with 5 mL of 1 N sodium hydroxide: the odor of ammonia is not noticeable.

Heavy metals, Method II 231: 0.001%.

Residual solvents 467: meets the requirements.

Assay— Weigh accurately about 2 g of Potassium Sodium Tartrate in a tared porcelain crucible, and ignite, gently at first, until the salt is thoroughly carbonized, protecting the carbonized salt from the flame at all times. Cool the crucible, place it in a glass beaker, and break up the carbonized mass with a glass rod. Without removing the glass rod or the crucible, add 50 mL of water and 50.0 mL of 0.5 N sulfuric acid VS, cover the beaker, and boil the solution for 30 minutes. Filter, and wash with hot water until the last washing is neutral to litmus. Cool the combined filtrate and washings, add methyl red-methylene blue TS, and titrate the excess acid with 0.5 N sodium hydroxide VS. Perform a blank determination (see Residual Titrations under Titrimetry 541). Each mL of 0.5 N sulfuric acid is equivalent to 52.54 mg of C4H4KNaO6.

Expert Committee : (MDGRE05) Monograph Development-Gastrointestinal Renal and Endocrine

USP29–NF24 Page 1777

Phone Number : 1-301-816-8251