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 of the major peak in the chromatogram of the Standard preparationas obtained in the Assay.

C: Shake a quantity of crushed Tablets,equivalent to about 100mg of ranitidine,with 2mLof water,and filter:the filtrate responds to the tests for Chloride á191ñ.

Medium: water;900mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Procedure— Determine the amount of C13H22N4O3Sdissolved from UVabsorbances at the wavelength of maximum absorbance at about 314nm using filtered portions of the solution under test,suitably diluted with water,if necessary,in comparison with a Standard solution having a known concentration of USP Ranitidine Hydrochloride RSin the same medium.

Tolerances— Not less than 80%(Q)of the labeled amount of C13H22N4O3Sis dissolved in 45minutes.

Test preparation— Prepare a filtered solution in methanol containing 20mg of ranitidine per mL(equivalent to 22.4mg of ranitidine hydrochloride per mL)by shaking an appropriate number of Tablets in a suitable volume of methanol until the tablets have disintegrated completely.

Standard preparations— Dissolve USP Ranitidine Hydrochloride RSin methanol to obtain a solution having a known concentration of 0.22mg per mL.Dilute portions of this Standard preparationquantitatively with methanol to obtain solutions having concentrations of 110µg per mL(Diluted standard preparation A),66µg per mL(Diluted standard preparation B),22µg per mL(Diluted standard preparation C),and 11µg per mL(Diluted standard preparation D),respectively.

Resolution preparation— Dissolve USP Ranitidine Related Compound A RS,5-[[(2-aminoethyl)thio]methyl]-N,N-dimethyl-2-furanmethanamine,hemifumarate salt,in methanol to obtain a solution having a known concentration of 1.27mg per mL.

Procedure— Apply separately 10µLof the Test preparation,the Standard preparation,and Diluted standard preparations A,B,C,and Dto 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 10µLof the Test preparationto the same plate,and on top of this application,apply 10µLof the Resolution preparation.Allow the spots to dry,and develop the chromatograms in a solvent system consisting of a mixture of ethyl acetate,isopropyl alcohol,ammonium hydroxide,and water (25:15:5:1)until the solvent front has moved not less than 15cm from the origin.Remove the plate from the developing chamber,mark the solvent front,and air-dry.Expose the plate to iodine vapor in a closed chamber until the chromatogram is fully revealed.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,and D:the system suitability requirements are met if there is complete resolution between the primary spots in the chromatogram of the combined Test preparationand the Resolution preparation,and if a spot is observed in the chromatogram of Diluted standard preparation D.No single secondary spot exhibits an intensity greater than that of Diluted standard preparation A(0.5%),and no other secondary spot exhibits an intensity greater than that of Diluted standard preparation B(0.3%).The sum of the intensities of all secondary spots obtained from the Test preparationcorrespond to not more than 2.0%.

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

Assay preparation— Transfer 10Tablets to a minimum of 250mLof Mobile phase,accurately measured.Shake the mixture until the Tablets have disintegrated completely,and filter.Dilute the filtrate quantitatively,and stepwise if necessary,with Mobile phaseto obtain a solution having a concentration of ranitidine similar to that of the Standard preparation.

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 Tablets taken by the formula: in which 314.40and 350.87are the molecular weights of ranitidine and ranitidine hydrochloride,respectively;Lis the labeled amount,in mg,of ranitidine in each tablet;Dis the concentration,in mg per mL,of ranitidine in the Assay preparation,based on the labeled quantity per Tablet 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.