A: Infrared Absorption 197M.

B: Ultraviolet Absorption 197U—

Solution: 10 µg per mL.

Medium: water.

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

Change to read:

Diluent, Mobile phase, Resolution solution, and Chromatographic system— Proceed as directed in the Assay.

Standard solution— Prepare as directed for Standard preparation in the Assay.

Test solution— Prepare as directed for Assay preparation in the Assay.

Procedure— Separately inject equal volumes (about 10 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and identify the ranitidine peak and the peaks due to impurities and degradation products listed in the table below. Measure the responses for the major peaks, and calculate the percentage of each impurity in the portion of Ranitidine Hydrochloride taken by the formula: USP31in which C is the concentration, in mg per mL, of ranitidine hydrochloride in the Standard solution; V is the volume, in mL, of the Test solution;USP31 W is the weight, in mg, of Ranitidine Hydrochloride taken to prepare the Test solution; ri is the peak response for each impurity obtained from the Test solution; and rS is the ranitidine peak response obtained from the Standard solution: not more than 0.3% of ranitidine bis-compound is found, not more than 0.1% of any other single impurity is found, and not more than 0.5% of total impurities is found.

(Official until July 1, 2008)

Change to read:

Phosphate buffer— Place approximately 1900 mL of water in a 2.0-L volumetric flask, accurately add 6.8 mL of phosphoric acid, and mix. Accurately add 8.6 mL of 50% sodium hydroxide solution, and dilute with water to volume. If necessary, adjust with 50% sodium hydroxide solution or phosphoric acid to a pH of 7.1, and filter.

Solution A— Prepare a mixture of Phosphate buffer and acetonitrile (98:2).

Solution B— Prepare a mixture of Phosphate buffer and acetonitrile (78:22).

Mobile phase— Use variable mixtures of Solution A and Solution B as directed for Chromatographic system. Make adjustments if necessary (see System Suitability under Chromatography 621).

Diluent— Use Solution A.

Standard preparation— Dissolve an accurately weighed quantity of USP Ranitidine Hydrochloride RS in Diluent to obtain a solution having a known concentration of about 0.125 mg of ranitidine hydrochloride per mL.

Resolution solution— Transfer about 1.3 mg of USP Ranitidine Resolution Mixture RS to a 10-mL volumetric flask, and dissolve in and dilute with Diluent to volume. [note—USP Ranitidine Resolution Mixture RS contains ranitidine hydrochloride and four related impurities: ranitidine amino alcohol hemifumarate, ranitidine diamine hemifumarate, ranitidine N-oxide, and ranitidine complex nitroacetamide.]

Assay preparation— Transfer about 25 mg of Ranitidine Hydrochloride, accurately weighed, to a 200-mL volumetric flask. Dissolve in and dilute with Diluent to volume, and mix.

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 230-nm detector and a 4.6-mm × 10-cm column containing 3.5-µm packing L1 that is stable from pH 1 to 12. The flow rate is about 1.5 mL per minute. The column temperature is maintained at 35. The chromatograph is programmed as follows. Chromatograph the Resolution solution, and identify the peaks using the table of impurities and degradation products (found above): the resolution, R, between the peaks for ranitidine N-oxide and ranitidine complex nitroacetamide is not less 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 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 percentageUSP31 of C13H22N4O3S·HCl in the portion of Ranitidine Hydrochloride taken by the formula: USP31in which CS and CU are the concentrations, in mg per mL, of ranitidine hydrochloride in the Standard preparation and the Assay preparation, respectively;USP31 and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.