Medium: 0.01Nhydrochloric acid;900mL.

Apparatus 1: 100rpm.

Time: 30minutes.

Procedure— Determine the amount of C2H5NO2dissolved,employing the procedure set forth in the Assay,using a filtered portion of the solution under test as the Assay preparationin comparison with a Standard solution having a known concentration of USP Acetohydroxamic Acid RSin the same Medium.

Tolerances— Not less than 85%(Q)of the labeled amount of C2H5NO2is dissolved in 30minutes.

Phosphate buffer,Pyridoxal 5-phosphate solution,and Standard solutions— Prepare as directed in the test for Limit of hydroxylamineunder Acetohydroxamic Acid.

Test solution— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 1500mg of acetohydroxamic acid to a 50-mLstoppered centrifuge tube.Add 30.0mLof water,shake for about 2minutes,and centrifuge.Pipet 15.0mLof the clear solution into a 50-mLbeaker,add just enough water to cover the electrode of a calibrated pHmeter,and while stirring,adjust with 0.5Mpotassium hydroxide to a pHof 7.4.Quantitatively transfer the contents of the beaker,with the aid of small portions of water,to a 50-mLvolumetric flask,dilute with water to volume,and mix.

Procedure— Proceed as directed in the test for Limit of hydroxylamineunder Acetohydroxamic Acid,except to calculate the percentage of hydroxylamine (H3NO)in the portion of Tablets taken by the formula: in which Ais the average weight,in mg,of each Tablet;Sis the weight,in mg,of the portion of Tablets taken to prepare the Test solution;Lis the labeled amount,in mg,of acetohydroxamic acid per Tablet;and the other terms are as defined therein.Not more than 0.5%is found.

Ferric chloride solution and Standard preparation— Prepare as directed in the Assayunder Acetohydroxamic Acid.

Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 500mg of acetohydroxamic acid,to a 1000-mLvolumetric flask,add about 500mLof 0.1Nhydrochloric acid,and shake for 1minute.Dilute with 0.1Nhydrochloric acid to volume,and mix.Filter,discarding the first 40mLof the filtrate.Use the clear filtrate as the Assay preparation.

Procedure— Proceed as directed for Procedurein the Assayunder Acetohydroxamic Acid.Calculate the quantity,in mg,of C2H5NO2in the portion of Tablets taken by the formula: