A: Tablets meet the requirements under Identification—Organic Nitrogenous Bases á181ñ.

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.

C: Asolution of Tablets meets the requirements of the tests for Chloride á191ñ.

Medium: water;900mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Procedure— Determine the amount of C13H18ClNO·HCl dissolved by employing UVabsorption at the wavelength of maximum absorbance of about 252nm on filtered portions of the solution under test,suitably diluted with 0.1Nhydrochloric acid,if necessary,in comparison with a Standard solution having a known concentration of USP Bupropion Hydrochloride RSin 0.1Nhydrochloric acid.

Tolerances— Not less than 80%(Q)of the labeled amount of C13H18ClNO·HCl is dissolved in 45minutes.

Diluent— Prepare a mixture of methanol and water (65:35).

pH7.0Phosphate buffer— Dissolve 6.8g of monobasic potassium phosphate and 1.164g of sodium hydroxide in water,dilute to 1000mL,and mix.

Mobile phase— Prepare a filtered and degassed mixture of methanol and pH7.0Phosphate buffer(65:35).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Bupropion Hydrochloride RSin Diluentto obtain a solution having a known concentration of about 0.6mg per mL.

Assay preparation— Transfer a number of Tablets to a volumetric flask suitable to obtain a solution having a final concentration of about 3.0mg of bupropion hydrochloride per mL.Add a portion of Diluent,equivalent to about one-half of the flask volume,and shake by mechanical means until the Tablets have disintegrated (between 30and 60minutes).Sonicate for 5minutes,dilute with Diluentto volume,and mix.Allow to stand for at least 30minutes,and pipet 10.0mLof the supernatant into a 50-mLvolumetric flask.Dilute with Diluentto volume,mix,and pass through a suitable filter.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 224-nm detector and a 4.6-mm ×15-cm column that contains 5-µm base-deactivated packing L1.The flow rate is about 1.2mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the tailing factor is not more than 2.5,and the relative standard deviation for replicate injections is not more than 2.0%.

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 amount,in mg,of bupropion hydrochloride (C13H18ClNO·HCl)in the portion of Tablets taken by the formula: in which Lis the labeled quantity,in mg,of bupropion hydrochloride in the Tablets;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 on the labeled quantity per Tablet and the extent of dilution;and rUand rSare the peak areas obtained from the Assay preparationand the Standard preparation,respectively.