A: Thin-Layer Chromatographic Identification Test á201ñ—

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: water;900mL.

Apparatus 1: 100rpm.

Time: 30minutes.

Procedure— Determine the amount of C25H30N2O5dissolved by employing the procedure set forth in the Assay,using a filtered portion of the solution under test as the Assay preparation,using methanol to prepare the Standard preparation,and making any necessary volumetric adjustments with water.

Tolerances— Not less than 80%(Q)of the labeled amount of C25H30N2O5is dissolved in 30minutes.

PROCEDURE FOR CONTENT UNIFORMITY—

Solvent,Buffered solvent,and Mobile phase— Prepare as directed in the Assay.

Resolution solution— Dissolve accurately weighed quantities of USP Quinapril Hydrochloride RS,USP Quinapril Related Compound A RS,and USP Quinapril Related Compound B RSin Solventto obtain a solution having known concentrations of about 0.1mg of USP Quinapril Hydrochloride RSand 0.005mg each of USP Quinapril Related Compound A RSand USP Quinapril Related Compound B RSper mL.

Standard solution— Dissolve accurately weighed quantities of USP Quinapril Related Compound A RSand USP Quinapril Related Compound B RSin Solvent,and dilute quantitatively,and stepwise if necessary,to obtain a solution having known concentrations of about 0.5µg each of USP Quinapril Related Compound A RSand USP Quinapril Related Compound B RSper mL.

Test solution— Use the Assay preparation.

Chromatographic system— Prepare as directed in the Assay.Chromatograph the Resolution solution,and record the peak areas as directed for Procedure:the relative retention times are about 0.6for quinapril related compound B,1.0for quinapril,and 2.0for quinapril related compound A;and the resolution,R,between quinapril and quinapril related compound Aand between quinapril and quinapril related compound Bis not less than 2.0.Chromatograph the Standard solution,and record the peak areas as directed for Procedure:the column efficiency is not less than 600theoretical plates;the tailing factor for the quinapril and quinapril related compound Apeaks is less than 1.5and that for the quinapril related compound Bpeak is less than 2.0;and the relative standard deviation for replicate injections is not more than 2.0%for quinapril and not more than 3.0%for each quinapril related compound.

Procedure— Separately inject equal volumes (about 20µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the areas of the major peaks.Calculate the quantity,in mg,of each quinapril related compound in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of the appropriate USP Reference Standard in the Standard solution;Dis the dilution factor used to prepare the Test solution;and rUand rSare the peak areas of the corresponding quinapril related compound obtained from the Test solutionand the Standard solution,respectively:not more than 1.0%of quinapril related compound Ais found;not more than 3.0%of quinapril related compound Bis found;and not more than 3.6%of total impurities is found.

Solvent— Prepare a mixture of water and acetonitrile (65:35).

Buffered solvent— Prepare a mixture of pH6.5,0.05Mdibasic potassium phosphate and acetonitrile (65:35).

Mobile phase— Prepare a filtered and degassed mixture of water,acetonitrile,and methanesulfonic acid (65:35:0.2).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Quinapril Hydrochloride RSin Solventto obtain a solution having a known concentration of about 1.08mg per mL.Quantitatively dilute with Buffered solventto obtain a solution having a known concentration of about 0.108mg per mL.

Assay preparation— Transfer 10Tablets to a 500-mLvolumetric flask,add about 300mLof Solvent,and sonicate until the Tablets have disintegrated.Shake by mechanical means for about 15minutes,dilute with Solventto volume,mix,and centrifuge.Dilute quantitatively,and stepwise if necessary,with Solventto obtain a solution having a concentration of about 0.1mg of quinapril per mL;and pass through a suitable filter,discarding the first portion of the filtrate.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 214-nm detector and a 6.0-mm ×4-cm column that contains 3-µm packing L10.The flow rate is about 1.2mLper minute.Chromatograph the Standard preparation,and record the peak areas as directed for Procedure:the column efficiency is not less than 600theoretical plates;the tailing factor is not more than 1.5;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20µL)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 quinapril (C25H30N2O5)in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Quinapril Hydrochloride RSin the Standard preparation;Dis the dilution factor used to prepare the Assay preparation;438.52and 474.98are the molecular weights of quinapril and quinapril hydrochloride,respectively;and rUand rSare the peak areas obtained from the Assay preparationand the Standard preparation,respectively.