A:Ultraviolet Absorption á197Uñ—

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.

FOR ORAL SOLUTION PACKAGED IN SINGLE-UNIT CONTAINERS: meets the requirements.

FOR ORAL SOLUTION PACKAGED IN MULTIPLE-UNIT CONTAINERS: meets the requirements.

NOTE—Throughout the following procedures,protect test or assay specimens,the USP Reference Standards,and solutions containing them,by conducting the procedures without delay,under subdued light,or using low-actinic glassware.

Mobile phase,System suitability solution,and Chromatographic system— Proceed as directed in the Assay.

Standard solution— Dissolve an accurately weighed quantity of USP Furosemide Related Compound B RSin Diluting solution,and dilute quantitatively,and stepwise if necessary,with Diluting solutionto obtain a solution having a known concentration of about 15.0µg per mL.

Test solution— Transfer an accurately measured portion of Oral Solution,equivalent to about 10mg of furosemide,to a 10-mLvolumetric flask,dissolve in and dilute with Diluting solutionto volume,and mix.

Procedure— Separately inject equal volumes (about 10µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the areas for the major peaks:the peak response of furosemide related compound Bobtained from the Test solutionis not greater than the corresponding peak response obtained from the Standard solution.

Mobile phase— Prepare a filtered and degassed mixture of water,acetonitrile,and glacial acetic acid (165:35:2).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Diluting solution— Prepare a mixture consisting of water,acetonitrile,and glacial acetic acid (22:22:1).

System suitability solution— Dissolve suitable quantities of USP Furosemide RS,USP Furosemide Related Compound A RS,and USP Furosemide Related Compound B RSin Diluting solutionto obtain a solution containing about 0.1mg of each per mL.

Standard preparation— Dissolve an accurately weighed quantity of USP Furosemide RSin Diluting solution,and dilute quantitatively,and stepwise if necessary,with Diluting solutionto obtain a solution having a known concentration of about 1mg per mL.

Assay preparation— Transfer an accurately measured portion of Oral Solution,equivalent to about 10mg of furosemide,to a 10-mLvolumetric flask,dissolve in and dilute with Diluting solutionto volume,and mix.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains packing L10.The flow rate is about 2mLper minute.Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the relative retention times are about 0.2for furosemide related compound B,1.0for furosemide,and 1.1for furosemide related compound A;the resolution,R,between furosemide and furosemide related compound Ais not less than 1.5;and the tailing factor for the furosemide peak is not more than 1.5.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 1.0%.

Procedure— Separately inject equal volumes (about 10µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the quantity,in mg,of furosemide (C12H11ClN2O5S)in the portion of Oral Solution taken by the formula: in which Cis the concentration,in mg per mL,of USP Furosemide RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.