A: The RFvalue of the principal spot observed in the chromatogram of the Test preparationobtained as directed in the Chromatographic puritytest corresponds to that obtained from the Standard preparation.

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.

Test preparation— Dilute Injection quantitatively with water,if necessary,to obtain a solution containing 25mg of ranitidine per mL.[NOTE—Use Injection of lower concentration without dilution as directed under Procedure.]

Standard preparation— Dissolve USP Ranitidine Hydrochloride RSin water to obtain a solution having a known concentration of 560µg per mL.Dilute portions of this Standard preparationquantitatively with water to obtain solutions having concentrations of 280µg per mL(Diluted standard preparation A),140µg per mL(Diluted standard preparation B),84µg per mL(Diluted standard preparation C),28µg per mL(Diluted standard preparation D),and 14µg per mL(Diluted standard preparation E),respectively.

Resolution preparation— Dissolve USP Ranitidine Related Compound A RSin methanol to obtain a solution having a known concentration of 1.27mg per mL.

Procedure— Apply separately 10µLof the Standard preparation,Diluted standard preparations A,B,C,Dand E,and the required volume of the Test preparation,equivalent to 250µg of ranitidine,to a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.In addition,apply separately a further loading of the same volume of the Test preparationto the same plate,and on top of this application,apply 10µLof the Resolution preparation.Perform the chromatography as described in Chromatographic purityunder Ranitidine Hydrochloride.Examine the plate and compare the intensities of any secondary spots observed in the chromatogram of the Test preparationwith those of the principal spots in the chromatograms of the Standard preparationand Diluted standard preparations(A,B,C,D,and E):the system suitability requirements are met when there is complete resolution between the primary spots of the Test preparationand the Resolution preparationand if a spot is observed in the chromatogram of Diluted standard preparation E.The major secondary spot is not greater in size or intensity than the principal spot produced by the Standard preparation(2.0%),and no other secondary spot is greater in size or intensity than the principal spot produced by Diluted standard preparation A(1.0%).The sum of the intensities of all secondary spots obtained from the Test preparationcorresponds to not more than 5.0%.

Mobile phase,Standard preparation,System suitability solution,andChromatographic system— Prepare as directed in the Assayunder Ranitidine Hydrochloride.

Assay preparation— Dilute an accurately measured volume of Injection,quantitatively and stepwise if necessary,with Mobile phaseto obtain a solution having a concentration of 0.1mg of ranitidine per mL.

Procedure— Separately inject equal volumes (about 10µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the area responses for the major peaks.Calculate the quantity,in mg,of C13H22N4O3Sin the portion of Injection taken by the formula: in which 314.40and 350.87are the molecular weights of ranitidine and ranitidine hydrochloride,respectively,Lis the labeled quantity of ranitidine in the Injection taken,Dis the concentration,in mg per mL,of ranitidine in the Assay preparationon the basis of the labeled quantity and the extent of dilution,Cis the concentration,in mg per mL,of USP Ranitidine Hydrochloride RSin the Standard preparation,and rUand rSare the peak area responses obtained from the Assay preparationand the Standard preparation,respectively.