A: Tablets meet the requirements under Identification—Organic Nitrogenous Bases 181.

B: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.

C: A solution of Tablets meets the requirements of the tests for Chloride 191.

Medium: water; 900 mL.

Apparatus 2: 50 rpm.

Time: 45 minutes.

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

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

(Official January 1, 2007)

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

pH 7.0 Phosphate buffer— Dissolve 6.8 g of monobasic potassium phosphate and 1.164 g of sodium hydroxide in water, dilute to 1000 mL, and mix.

Mobile phase— Prepare a filtered and degassed mixture of methanol and pH 7.0 Phosphate buffer (65:35). Make adjustments if necessary (see System Suitability under Chromatography 621).

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

Assay preparation— Transfer a number of Tablets to a volumetric flask suitable to obtain a solution having a final concentration of about 3.0 mg 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 30 and 60 minutes). Sonicate for 5 minutes, dilute with Diluent to volume, and mix. Allow to stand for at least 30 minutes, and pipet 10.0 mL of the supernatant into a 50-mL volumetric flask. Dilute with Diluent to volume, mix, and pass through a suitable filter.

Chromatographic system (see Chromatography 621)— 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 1.2 mL per 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 10 µL) of the Standard preparation and the Assay preparation into 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 L is the labeled quantity, in mg, of bupropion hydrochloride in the Tablets; C is the concentration, in mg per mL, of USP Bupropion Hydrochloride RS in the Standard preparation; D is 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 rU and rS are the peak areas obtained from the Assay preparation and the Standard preparation, respectively.