A: Infrared Absorption á197Kñ—

Test specimen— Transfer a quantity of finely powdered Tablets,equivalent to about 100mg of hydralazine hydrochloride,to a glass-stoppered flask.Add 40mLof 1Nhydrochloric acid,shake by mechanical means for 5minutes,and filter,discarding the first few mLof the filtrate.Place 20mLof the filtrate in a separator,wash with 10mLof methylene chloride,and discard the methylene chloride washing.Mix the aqueous solution in the separator with 2mLof sodium nitrite solution (14in 1000),add 10mLof methylene chloride,shake by mechanical means for 5minutes,and allow the layers to separate.Pass the methylene chloride layer through a filter of anhydrous sodium sulfate that previously has been washed with methylene chloride,and collect the solution in a 50-mLbeaker.Evaporate with the aid of gentle heat and a stream of dry nitrogen to dryness.

B: The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay .

Medium: 0.01Nhydrochloric acid;900mL.

Apparatus 1: 100rpm.

Time: 45minutes.

Procedure— Determine the amount of C8H8N4·HCl dissolved by employing UVabsorption at the wavelength of maximum absorbance at about 260nm on filtered portions of the solution under test,suitably diluted with Dissolution Medium,in comparison with a Standard solution having a known concentration of USP Hydralazine Hydrochloride RSin the same Medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C8H8N4·HCl is dissolved in 45minutes.

Mobile phase,Standard preparation,Resolution solution,and Chromatographic system— Prepare as directed in the Assayunder Hydralazine Hydrochloride.

Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 100mg of hydralazine hydrochloride,to a 250-mLvolumetric flask,dissolve in and dilute with 0.1Nacetic acid to volume,and centrifuge.Pipet 10mLof the clear liquid into a 100-mLvolumetric flask,dilute with 0.1Nacetic acid to volume,mix,and filter.

Procedure— Proceed as directed in the Assayunder Hydralazine Hydrochloride.Calculate the quantity,in mg,of hydralazine hydrochloride (C8H8N4·HCl)in the portion of Tablets taken by the formula: in which the terms are as defined therein.