A: Triturate a quantity of powdered Tablets,equivalent to about 100mg of menadiol sodium diphosphate,with a mixture of 10mLof water and 10mLof 2Nsulfuric acid,centrifuge the mixture,and filter the supernatant.To the filtrate add 1mLof 0.5Nceric sulfate,mix,extract with 10mLof chloroform,and centrifuge.Evaporate the chloroform extract on a steam bath just to dryness,then dry at 80for 1hour:the IRabsorption 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 50mg of the menadione obtained in Identificationtest Aadd 5mLof water,then add 75mg 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 50mL,and mix.To 2mLof the solution add 2mLof alcoholic ammonia (prepared by mixing equal volumes of alcohol and ammonium hydroxide),shake,and add 3drops of ethyl cyanoacetate:a deep purplish blue color is produced,and,on the addition of 1mLof sodium hydroxide solution (1in 3),it changes to green and then to yellow.

C: Triturate a quantity of powdered Tablets,equivalent to about 20mg of menadiol sodium diphosphate,with 10mLof water,centrifuge the mixture,filter the supernatant,and evaporate to a volume of about 2mL.Add 2drops of nitric acid and 1mLof sulfuric acid,and heat slowly to the evolution of white fumes.Cool,cautiously dilute with water to about 10mL,and filter if not clear.Render the filtrate slightly alkaline to litmus with 6Nammonium hydroxide,then render it acid with nitric acid,and add to the warm solution 3mLof ammonium molybdate TS:a yellow precipitate is formed within a few minutes.

Medium: 0.1Nhydrochloric acid;900mL.

Apparatus 1: 100rpm.

Time: 30minutes.

Procedure— Determine the amount of C11H8Na4O8P2·6H2Odissolved from UVabsorbances at the wavelength of maximum absorbance at about 227nm of filtered portions of the solution under test,suitably diluted with Dissolution Medium,in comparison with a Standard solution having a known concentration of Menadiol Sodium Diphosphate,previously subjected to the Assayand dried in vacuum over phosphorus pentoxide for 4hours,in the same Medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C11H8Na4O8P2·6H2Ois dissolved in 30minutes.

Procedure for content uniformity— [NOTE—Use low-actinic glassware.]Transfer 1finely powdered Tablet to a glass-stoppered centrifuge tube,add 25mLof pH8.0phosphate buffer (see under Solutionsin the section Reagents,Indicators,and Solutions),and shake vigorously for several minutes.Filter into a 50-mLvolumetric flask,rinse the centrifuge tube,and filter with three 5-mLportions of pH8.0phosphate buffer,adding the rinsings to the volumetric flask,dilute with pH8.0phosphate buffer to volume,and mix.Dilute a portion of this solution quantitatively and stepwise,if necessary,with pH8.0phosphate buffer to provide a solution containing approximately 40µg 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 4hours,in the same medium having a known concentration of about 40µg per mL,at the wavelength of maximum absorbance at about 297nm,with a suitable spectrophotometer,using pH8.0phosphate buffer as the blank.Calculate the quantity,in mg,of C11N8Na4O8P2·6H2Oin the Tablet taken by the formula: in which Tis the labeled quantity,in mg,of menadiol sodium diphosphate in the Tablet,Cis the concentration,in µg per mL,of C11H8Na4O8P2·6H2Oin the standard solution,Dis 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 AUand ASare the absorbances of the solution from the Tablet and the standard solution,respectively.