A: Ultraviolet Absorption á197Uñ—

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

Standard solution: 8µg per mL.

Medium: 0.1Nhydrochloric acid.

B: Shake a Tablet with 10mLof methanol until it disintegrates,and filter:the filtrate responds to Identificationtest Cunder Moricizine Hydrochloride.

Medium: 0.1Nhydrochloric acid;900mL.

Apparatus 2: 50rpm.

Time: 30minutes.

Procedure— Determine the amount of moricizine hydrochloride (C22H25N3O4S·HCl)dissolved from UVabsorbance at about 267nm 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 RSin the same medium.

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

Mobile phase— Dissolve 1.08g of sodium 1-octanesulfonate in 580mLof water,add 420mLof acetonitrile,20mLof glacial acetic acid,and 1mLof triethylamine.Adjust with 5Nsodium hydroxide to an apparent pHof 4.5.Mix,and filter through a filter having a porosity of 0.5µm or finer.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

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

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

Standard solution— Prepare a solution of USP Moricizine Hydrochloride RSin Diluentcontaining 0.10mg per mL.Transfer 5.0mLof this solution to a 50-mLvolumetric flask,add 20.0mLof Internal standard solution,dilute with Diluentto volume,and mix.[NOTE—Protect this solution from light.]

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

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains packing L7and is maintained at a constant temperature of about 35.The flow rate is about 2.5mLper minute.Chromatograph the Standard solution,and record the peak responses as directed under Procedure:the relative retention times are about 0.6for moricizine and 1.0for 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 20µL)of the Standard solutionand the Test solutioninto 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 Cis the concentration,in mg per mL,of USP Moricizine Hydrochloride RSin the Standard solution,Lis the labeled amount,in mg,of moricizine hydrochloride in each Tablet,Riis the ratio of the peak areas of an individual impurity peak to the butamben peak obtained from the Test solution,and RSis 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 Assayunder Moricizine Hydrochloride.

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

Procedure— Proceed as directed for Procedurein the Assayunder Moricizine Hydrochloride.Calculate the quantity,in mg,of moricizine hydrochloride (C22H25N3O4S·HCl)in each Tablet by the formula: in which Cis the concentration,in mg per mL,of USP Moricizine Hydrochloride RSin the Standard preparation,Nis the number of Tablets taken,and RUand RSare the ratios of the peak area responses of the moricizine peak to the butamben peak obtained from the Assay preparationand the Standard preparation,respectively.