Menadiol Sodium Diphosphate
(men'' a dye' ol soe' dee um dye fos' fate).
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C11H8Na4O8P2·6H2O 530.17

1,4-Naphthalenediol, 2-methyl-, bis(dihydrogen phosphate), tetrasodium salt, hexahydrate.
2-Methyl-1,4-naphthalenediol bis(dihydrogen phosphate) tetrasodium salt, hexahydrate [6700-42-1].

Anhydrous 422.09 [131-13-5].
» Menadiol Sodium Diphosphate contains not less than 97.5 percent and not more than 102.0 percent of C11H8Na4O8P2, calculated on the anhydrous basis.
Packaging and storage— Preserve in tight, light-resistant containers, and store in a cold place.
A: Dissolve about 200 mg of Menadiol Sodium Diphosphate in 10 mL of water, add 10 mL of 2 N sulfuric acid, 10 mL of 0.1 N ceric sulfate, and 1 mL of 30 percent hydrogen peroxide previously diluted with 5 mL of water, and extract the solution with two 10-mL portions of chloroform. Gently evaporate the clear chloroform solution on a steam bath to dryness, and dry the residue at 80 for 1 hour: the menadione so obtained melts between 104 and 107.
B: To 50 mg of the dried residue obtained in Identification test A add 5 mL of water, then add 75 mg of sodium bisulfite, and heat on a steam bath, shaking vigorously until the substance is dissolved and the solution is practically colorless. Dilute with water to 50 mL, and mix. To 2 mL of the solution add 2 mL of alcoholic ammonia (prepared by mixing equal volumes of alcohol and ammonium hydroxide), shake, and add 3 drops of ethyl cyanoacetate: a deep purplish blue color is produced, and on the addition of 1 mL of sodium hydroxide solution (1 in 3), it changes to green and then to yellow.
C: To about 20 mg contained in a small beaker add 1 mL of water, 2 drops of nitric acid, and 1 mL of sulfuric acid, and heat slowly to the evolution of white fumes. Cool, cautiously dilute with water to about 10 mL, and filter if not clear. Render the filtrate slightly alkaline to litmus with 6 N ammonium hydroxide, then render it acid with nitric acid, and add to the warm solution 3 mL of ammonium molybdate TS: a yellow precipitate is formed within a few minutes.
Water, Method I 921: between 19.0% and 21.5%.
Assay— Dissolve about 100 mg of Menadiol Sodium Diphosphate, accurately weighed, in 25 mL of water, and add 25 mL of glacial acetic acid and 25 mL of 3 N hydrochloric acid. Titrate the solution with 0.02 N ceric sulfate VS, determining the endpoint potentiometrically using a calomel-platinum electrode system. Each mL of 0.02 N ceric sulfate is equivalent to 4.221 mg of C11H8Na4O8P2.
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Monograph Sujatha Ramakrishna, Ph.D.
Senior Scientific Liaison
(SM22010) Monographs - Small Molecules 2
USP35–NF30 Page 3796
Pharmacopeial Forum: Volume No. 29(5) Page 1531