Medium: water;500mL.

Apparatus 2: 50rpm.

Time: 30minutes.

Stock standard solution— Weigh accurately about 5mg of USP Triazolam RS,dissolve in and dilute with methanol to 200.0mL,and mix.

Working standard solution— For each 0.125mg of the labeled amount of triazolam per Tablet,add 2.0mLof Stock standard solutionto a 200-mLvolumetric flask.Dilute with water to volume,and mix.

Procedure— After 30minutes,withdraw a portion of the solution under test,and filter immediately.Inject equal volumes (about 200µL)of this solution and the Working standard solutioninto a liquid chromatograph (see Chromatography á621ñ)equipped with a detector capable of monitoring UVabsorbance at 222nm and a 4.6-mm ×10-cm stainless steel column containing packing L7.The mobile phase is a mixture of water and acetonitrile (60:40).The flow rate is about 1mLper minute.The relative standard deviation of the peak response for the Working standard solutionis not more than 3.0%,and the number of theoretical plates is not less than 500.Calculate the percentage of C17H12Cl2N4dissolved by the formula: in which rUand rSare the peak responses of the solution under test and the Working standard solution,respectively,Cis the concentration,in mg per mL,of USP Triazolam RSin the Working standard solution,and Lis the labeled amount,in mg,of triazolam in the Tablet.

Tolerances— Not less than 70%(Q)of the labeled amount of C17H12Cl2N4is dissolved in 30minutes.

Procedure for content uniformity—

Mobile phase and Chromatographic system—Proceed as directed in the Assayunder Triazolam.

Internal standard solution— Prepare a solution of alprazolam in acetonitrile having a concentration of about 0.025mg per mL.

Standard preparation— Dissolve about 3.2mg of USP Triazolam RS,accurately weighed,in 100.0mLof Internal standard solution,and mix.

Test preparation— Transfer 1Tablet to a container,add about 0.4mLof water directly onto the Tablet,allow to stand for about 2minutes,and swirl the container to disperse the Tablet.For each 0.25mg of the labeled amount of triazolam in the Tablet,add 10.0mLof Internal standard solutionto the container.Shake,and centrifuge if necessary.

Procedure— Proceed as directed for Procedurein the Assayunder Triazolam.Calculate the quantity,in mg,of C17H12Cl2N4in the Tablet taken by the formula: in which Vis the volume,in mL,of Internal standard solutionin the Test preparation.

Mobile phase and Chromatographic system—Proceed as directed in the Assayunder Triazolam.

Internal standard solution— Prepare a solution of alprazolam in acetonitrile,having a concentration of 0.1mg per mL.

Standard stock solution— Dissolve an accurately weighed quantity of USP Triazolam RSin acetonitrile,and dilute with acetonitrile to obtain a solution having a known concentration of about 0.1mg per mL.

Standard preparation— Transfer 8.0mLof Standard stock solutionto a 200-mLvolumetric flask,add 8.0mLof Internal standard solution,dilute with acetonitrile to volume,and mix.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed quantity of the powder,equivalent to about 0.8mg of triazolam,to a 200-mLvolumetric flask.Add 2mLof water,mix,and allow to stand for 10minutes.Mix vigorously for 10seconds,and add 8.0mLof Internal standard solution,shake vigorously for 10minutes,dilute with acetonitrile to volume,and mix.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the area responses for the major peaks.Calculate the quantity,in mg,of C17H12Cl2N4in the portion of Triazolam taken by the formula: in which Cis the concentration,in mg per mL,of USP Triazolam RSin the Standard preparation,and RUand RSare the ratios of the internal standard peak area to the triazolam peak area obtained from the Assay preparationand the Standard preparation,respectively.