A: Triturate a quantity of powdered Tablets, equivalent to about 100 mg of menadiol sodium diphosphate, with a mixture of 10 mL of water and 10 mL of 2 N sulfuric acid, centrifuge the mixture, and filter the supernatant. To the filtrate add 1 mL of 0.5 N ceric sulfate, mix, extract with 10 mL of chloroform, and centrifuge. Evaporate the chloroform extract on a steam bath just to dryness, then dry at 80 for 1 hour: the IR absorption spectrum of a potassium bromide dispersion of the menadione so obtained exhibits maxima at the same wavelengths as that of a similar preparation of USP Menadione RS.

B: To 50 mg of the menadione 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 almost colorless. Add water to make 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: Triturate a quantity of powdered Tablets, equivalent to about 20 mg of menadiol sodium diphosphate, with 10 mL of water, centrifuge the mixture, filter the supernatant, and evaporate to a volume of about 2 mL. Add 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.

Medium: 0.1 N hydrochloric acid; 900 mL.

Apparatus 1: 100 rpm.

Time: 30 minutes.

Procedure— Determine the amount of C11H8Na4O8P2·6H2O dissolved from UV absorbances at the wavelength of maximum absorbance at about 227 nm on filtered portions of the solution under test, suitably diluted with Medium, in comparison with a standard solution prepared by dissolving in the same Medium an accurately weighed quantity of Menadiol Sodium Diphosphate, previously dried in vacuum over phosphorus pentoxide for 4 hours, the dried sample having a known concentration determined by titration with 0.01 N ceric sulfate VS as directed in the Assay.

Tolerances— Not less than 75% (Q) of the labeled amount of C11H8Na4O8P2·6H2O is dissolved in 30 minutes.

Procedure for content uniformity— [NOTE—Use low-actinic glassware.] Transfer 1 finely powdered Tablet to a glass-stoppered centrifuge tube, add 25 mL of pH 8.0 phosphate buffer (see under Solutions in the section Reagents, Indicators, and Solutions), and shake vigorously for several minutes. Filter into a 50-mL volumetric flask, rinse the centrifuge tube, and filter with three 5-mL portions of pH 8.0 phosphate buffer, adding the rinsings to the volumetric flask, dilute with pH 8.0 phosphate buffer to volume, and mix. Dilute a portion of this solution quantitatively and stepwise, if necessary, with pH 8.0 phosphate buffer to provide a solution containing approximately 40 µg of menadiol sodium diphosphate per mL. Concomitantly determine the absorbances of this solution and of a solution of Menadiol Sodium Diphosphate, previously dried in vacuum over phosphorus pentoxide for 4 hours, in the same Medium having a known concentration of about 40 µg per mL, at the wavelength of maximum absorbance at about 297 nm, with a suitable spectrophotometer, using pH 8.0 phosphate buffer as the blank. Calculate the quantity, in mg, of C11N8Na4O8P2·6H2O in the Tablet taken by the formula: in which T is the labeled quantity, in mg, of menadiol sodium diphosphate in the Tablet, C is the concentration, in µg per mL, of C11H8Na4O8P2·6H2O in the Standard solution, D is the concentration, in µg per mL, of menadiol sodium diphosphate in the test solution, based upon the labeled quantity per Tablet and the extent of dilution, and AU and AS are the absorbances of the solution from the Tablet and the standard solution, respectively.

(Official January 1, 2007)