A:Infrared Absorption á197Kñ—

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 2: 50rpm.

Times: 1,4,and 8hours.

Procedure— Determine the amount of C13H18ClNO·HCl dissolved by employing UVabsorption at the wavelength of maximum absorbance at about 298nm,using a 1.0-cm cell,on filtered portions of the solution under test,suitably diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Bupropion Hydrochloride RSin the same Medium.

Tolerances— The percentages of the labeled amount of C13H18ClNO·HCl dissolved at the times specified conform to Acceptance Table 1.

PROCEDURE FOR CONTENT UNIFORMITY—

Solution A,Solution B,Mobile phase,System suitability solution 1,andSystem suitability solution 2— Proceed as directed in the Assay.

Standard solution— Dissolve accurately weighed quantities of USP Bupropion Hydrochloride RSand USP Bupropion Hydrochloride Related Compound E RSin a mixture of 0.001Nhydrochloric acid and methanol (80:20)to obtain a solution having known concentrations of about 0.6mg per mLand 0.0024mg per mL,respectively.

Test solution— Use the Assay preparation.

Chromatographic system— Proceed as directed in the Assay,except to use the Standard solutioninstead of the Standard preparation.

Procedure— Separately inject equal volumes (about 5µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the percentage of bupropion hydrochloride related compound Ein the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Bupropion Hydrochloride Related Compound E RSin the Standard solution;Dis the concentration,in mg per mL,of bupropion hydrochloride in the Test solution,based on the number of Tablets taken,the labeled quantity per Tablet,and the extent of dilution;and rUand rSare the peak responses for bupropion hydrochloride related compound Eobtained from the Test solutionand the Standard solution,respectively:not more than 0.4%of bupropion hydrochloride related compound Eis found.Calculate the percentage of each additional impurity in the portion of Tablets taken by the formula: in which Fis the relative response factor for each impurity (see the accompanying table for values);riis the peak response for each impurity obtained from the Test solution;and rSis the peak response for bupropion hydrochloride obtained from the Standard solution.See the accompanying table for limits of individual impurities based upon Tablet strength.

Solution A— Prepare a filtered and degassed mixture of water,acetonitrile,and trifluoroacetic acid (90:10:0.04).

Solution B— Prepare a filtered and degassed mixture of acetonitrile,water,and trifluoroacetic acid (95:5:0.03).

Mobile phase— Use variable mixtures of Solution Aand Solution Bas directed for Chromatographic system.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

System suitability solution 1— Prepare separate solutions containing accurately weighed quantities of USP Bupropion Hydrochloride Related Compound C RSand USP Bupropion Hydrochloride Related Compound F RSin methanol to obtain solutions having concentrations of about 0.20mg per mL.Transfer accurately measured volumes of these solutions to a suitable flask,and dilute with a mixture of 0.001Nhydrochloric acid and methanol (80:20)to obtain a solution having a concentration of about 0.0018mg of USP Bupropion Hydrochloride Related Compound C RSper mLand 0.018mg of USP Bupropion Hydrochloride Related Compound F RSper mL.

System suitability solution 2— Prepare a solution containing an accurately weighed quantity of m-chlorobenzoic acid to obtain a solution having a concentration of about 0.09mg per mL.Dilute an accurately measured volume of this solution with a mixture of 0.001Nhydrochloric acid and methanol (80:20)to obtain a solution having a concentration of about 0.0018mg of m-chlorobenzoic acid per mL.

Standard preparation— Dissolve an accurately weighed quantity of USP Bupropion Hydrochloride RSin a mixture of 0.001Nhydrochloric acid and methanol (80:20)to obtain a solution having a known concentration of about 0.6mg of bupropion hydrochloride per mL.

Assay preparation— Transfer a number of Tablets to a suitable homogenizer vessel containing an accurately measured volume of methanol to obtain a concentration of about 3.0mg of bupropion hydrochloride per mL.Immediately homogenize the sample for 30seconds at 20,000rpm.Allow to extract for 3minutes,and follow by two additional 10-second pulses,each at 20,000rpm,pausing 3minutes between these pulses to ensure complete extraction.Pass a portion of the solution through a nylon filter having a 0.45-µm porosity,discarding the first 2to 4mLof the filtrate.Pipet 10.0mLof the filtrate into a 50-mLvolumetric flask,and add about 25mLof 0.001Nhydrochloric acid.Allow to cool to room temperature,and dilute with 0.001Nhydrochloric acid to volume.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 226-nm detector and a 4.6-mm ×10-cm column that contains 3.5-µm packing L1.The flow rate is about 1.5mLper minute.The chromatograph is programmed as follows. Chromatograph System suitability solution 1,System suitability solution 2,and the Standard preparation,and record the peak areas as directed for Procedure:the resolution,R,between bupropion hydrochloride related compound Cand bupropion hydrochloride related compound Fis not less than 1.5;the relative response factor for System suitability solution 2is between 0.22and 0.26when calculated using the peak obtained in the Standard preparation;the tailing factor is not more than 1.9;and the relative standard deviation for replicate injections of the Standard preparationis not more than 1.5%.

Procedure— Separately inject equal volumes (about 5µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the amount,in mg,of bupropion hydrochloride (C13H18ClNO·HCl)in the portion of Tablets taken by the formula: in which Tis the labeled quantity,in mg,of bupropion hydrochloride in the Tablet;Cis the concentration,in mg per mL,of USP Bupropion Hydrochloride RSin the Standard preparation;Dis the concentration,in mg per mL,of bupropion hydrochloride in the Assay preparation,based upon the labeled quantity per Tablet and the extent of dilution;and rUand rSare the peak responses for bupropion hydrochloride obtained from the Assay preparationand the Standard preparation,respectively.