A: Dissolve a portion of Capsules,equivalent to about 30mg of flurazepam hydrochloride,in 10mLof methanol,filter,and proceed as directed for Identificationtest Cunder Flurazepam Hydrochloride.

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

C: Capsules meet the requirements under Identification—Organic Nitrogenous Bases á181ñ.

Medium: 0.01Nhydrochloric acid;900mL.

Apparatus 1: 100rpm.

Time: 20minutes.

Standard solution— Prepare a solution of USP Flurazepam Hydrochloride RShaving an accurately known concentration similar to the concentration of the solution under test.Pipet 5mLof this solution to a 10-mLvolumetric flask,and dilute with 1%ammonium acetate to volume.

Test solution— Pipet 5mLof a filtered portion of the solution under test into a 10-mLvolumetric flask,and dilute with 1%ammonium acetate to volume.

Procedure— Determine the amount of C21H23ClFN3O·2HCl dissolved,using the Chromatographic systemas set forth in the Related compoundstest under Flurazepam Hydrochloride.

Tolerances— Not less than 75%(Q)of the labeled amount of C21H23ClFN3O·2HCl is dissolved in 20minutes.

Mobile phase ,System suitability solution,and Chromatographic system—Prepare as directed for Related compoundsunder Flurazepam Hydrochloride.

Standard preparation— Dissolve an accurately weighed quantity of USP Flurazepam Hydrochloride RSin methanol,and dilute quantitatively,and stepwise if necessary,with Mobile phaseto obtain a solution having a known concentration of about 0.15mg per mL.Prepare fresh daily.

Assay preparation— [NOTE—Prepare fresh daily.]Weigh and mix the contents of not fewer than 20Capsules.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 30mg of flurazepam hydrochloride,to a 200-mLvolumetric flask.Add 40mLof methanol,and shake by mechanical means for 10minutes.Add 10mLof 1%ammonium acetate,and shake by mechanical means for 5minutes.Dilute with Mobile phaseto volume,mix and sonicate for 2minutes,and filter.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of flurazepam hydrochloride (C21H23ClFN3·2HCl)in the portion of Capsules taken by the formula: in which Cis the concentration,in mg per mL,of USP Flurazepam Hydrochloride RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.