A: Ultraviolet Absorption 197U—

Test solution— Transfer a portion of finely ground Tablets, equivalent to about 50 mg of moricizine hydrochloride, to a 250-mL volumetric flask, add about 100 mL of 0.1 N hydrochloric acid, shake by mechanical means for 15 minutes, dilute with 0.1 N hydrochloric acid to volume, and mix. Filter a portion of this solution, discarding the first 10 mL of the filtrate. Transfer 10 mL of the filtrate to a 250-mL volumetric flask, dilute with 0.1 N hydrochloric acid to volume, and mix.

Standard solution: 8 µg per mL.

Medium: 0.1 N hydrochloric acid.

B: Shake a Tablet with 10 mL of methanol until it disintegrates, and filter: the filtrate responds to Identification test C under Moricizine Hydrochloride.

Medium: 0.1 N hydrochloric acid; 900 mL.

Apparatus 2: 50 rpm.

Time: 30 minutes.

Procedure— Determine the amount of moricizine hydrochloride (C22H25N3O4S·HCl) dissolved from UV absorbance at about 267 nm of filtered portions of the solution under test, suitably diluted with Dissolution Medium, in comparison with a Standard solution having a known concentration of USP Moricizine Hydrochloride RS in the same medium.

Tolerances— Not less than 75% (Q) of the labeled amount of moricizine hydrochloride (C22H25N3O4S·HCl) is dissolved in 30 minutes.

Mobile phase— Dissolve 1.08 g of sodium 1-octanesulfonate in 580 mL of water, add 420 mL of acetonitrile, 20 mL of glacial acetic acid, and 1 mL of triethylamine. Adjust with 5 N sodium hydroxide to an apparent pH of 4.5. Mix, and filter through a filter having a porosity of 0.5 µm or finer. Make adjustments if necessary (see System Suitability under Chromatography 621).

Diluent— Prepare a mixture of 0.02 N hydrochloric acid and acetonitrile (58:42).

Internal standard solution— Prepare a solution of butamben in Diluent containing about 0.2 mg per mL.

Standard solution— Prepare a solution of USP Moricizine Hydrochloride RS in Diluent containing 0.10 mg per mL. Transfer 5.0 mL of this solution to a 50-mL volumetric flask, add 20.0 mL of Internal standard solution, dilute with Diluent to volume, and mix. [note—Protect this solution from light.]

Test solution— Transfer 10 Tablets to a 1000-mL flask, add 500.0 mL of Diluent, sonicate until the Tablets are disintegrated, and then shake by mechanical means for 30 minutes. Filter this solution, discarding the first 10 mL of the filtrate. Transfer 25.0 mL of the filtrate to a 50-mL volumetric flask, add 20.0 mL of Internal standard solution, dilute with Diluent to volume, and mix. [note—Protect this solution from light.]

Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 25-cm column that contains packing L7 and is maintained at a constant temperature of about 35. The flow rate is about 2.5 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed under Procedure: the relative retention times are about 0.6 for moricizine and 1.0 for butamben, the resolution, R, between the moricizine peak and the butamben peak is not less than 2, and the relative standard deviation for replicate injections is not more than 5%.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms for a period of time that is five times the elution time of moricizine, and measure the responses for the peaks, except for any that elute before moricizine. Calculate the percentage of each impurity peak that elutes after butamben in the portion of Moricizine Hydrochloride taken by the formula: in which C is the concentration, in mg per mL, of USP Moricizine Hydrochloride RS in the Standard solution, L is the labeled amount, in mg, of moricizine hydrochloride in each Tablet, Ri is the ratio of the peak areas of an individual impurity peak to the butamben peak obtained from the Test solution, and RS is the ratio of the peak areas of the moricizine peak to the butamben peak obtained from the Standard solution. The first impurity eluting after the butamben peak is not more than 0.50%, and the second impurity eluting after butamben is not more than 0.25%.

Mobile phase , Diluent, Internal standard solution, Standard preparation, and Chromatographic system—Proceed as directed in the Assay under Moricizine Hydrochloride.

Assay preparation— Transfer an accurately counted number of Tablets, equivalent to about 4000 mg of moricizine hydrochloride, to a 2000-mL flask, add 1000.0 mL of Diluent, and sonicate until the Tablets have disintegrated. Shake by mechanical means for 30 minutes. Filter a portion of this solution, discarding the first 10 mL of the filtrate. Cover the filter funnel with a watch glass to minimize evaporation of the solvent. Transfer 25.0 mL of the filtrate and 20.0 mL of Internal standard solution to a 100-mL volumetric flask, dilute with Diluent to volume, and mix. [note—Protect this solution from light.]

Procedure— Proceed as directed for Procedure in the Assay under Moricizine Hydrochloride. Calculate the quantity, in mg, of moricizine hydrochloride (C22H25N3O4S·HCl) in each Tablet by the formula: in which C is the concentration, in mg per mL, of USP Moricizine Hydrochloride RS in the Standard preparation, N is the number of Tablets taken, and RU and RS are the ratios of the peak area responses of the moricizine peak to the butamben peak obtained from the Assay preparation and the Standard preparation, respectively.