A:Thin-Layer Chromatographic Identification Test á201ñ—

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.

Medium: 0.1Nhydrochloric acid;900mL.

Apparatus 2: 50rpm.

Time: 60minutes.

Procedure— Determine the amount of C22H23ClN2O2dissolved from UVabsorption at the wavelength of maximum absorbance at about 280nm on filtered portions of the solution under test,suitably diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Loratadine RSin the sameMedium.

Tolerances— Not less than 80%(Q)of the labeled amount of C22H23ClN2O2is dissolved in 60minutes.

0.01M Dibasic potassium phosphate,0.6M Dibasic potassium phosphate,Mobile phase,0.05N Hydrochloric acid,andDiluent— Proceed as directed in the Assayunder Loratadine.

Standard stock solution— Prepare as directed for Standard preparationin the Assay under Loratadine.

Standard solution— Pipet 5.0mLof the Standard stock solution into a 100-mLvolumetric flask,and dilute with Diluentto volume.Dilute quantitatively,and stepwise if necessary,with Diluentto obtain a solution having a known concentration of about 0.8µg per mL.

Test solution— Use the Assay preparation.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×15-cm column that contains 5-µm packing L7.The flow rate is about 1mLper minute.Chromatograph the Test solution,and record the peak areas as directed forProcedure:the relative retention times are about 0.79for 4-(8-chloro-11-fluoro-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-yl)-1-piperidinecarboxylate ethyl and 1.0for loratadine.Chromatograph the Standard solution,and record the peak areas of the main peak as directed for Procedure:the relative standard deviation for replicate injections is not more than 4.0%.

Procedure— Separately inject equal volumes (about 50µL)of the Test solutionand the Standard solutioninto the chromatograph,record the chromatograms,and measure all of the peak area responses in the Test solutionand the peak area of the main peak in the Standard solution.Calculate the percentage of each impurity in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Loratadine RSin the Standard solution;Lis the labeled quantity,in mg,of loratadine in each Tablet taken;riis the peak area response for each impurity in the Test solution;and rSis the peak area response of loratadine in the Standard solution:not more than 0.2%of 4-(8-chloro-11-fluoro-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-yl)-1-piperidinecarboxylate ethyl is found;not more than 0.1%of any other individual impurity is found;and the sum of all impurities,other than 4-(8-chloro-11-fluoro-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-yl)-1-piperidinecarboxylate ethyl,is not more than 0.1%.

0.01M Dibasic potassium phosphate,0.6M Dibasic potassium phosphate,Mobile phase,0.05N Hydrochloric acid,Diluent,andStandard preparation— Proceed as directed in the Assayunder Loratadine.

Assay preparation— Transfer 10Tablets into a 250-mLvolumetric flask,add 100mLof 0.05N Hydrochloric acid,and shake for 40minutes or until the Tablets are completely disintegrated.Add 75mLof a mixture of methanol and acetonitrile (1:1),and mix.Add 20mLof 0.6M Dibasic potassium phosphate,and mix for 5minutes.Dilute with a mixture of methanol and acetonitrile (1:1)to volume,and mix.

Chromatographic system (see Chromatography á621ñ)— Prepare as directed in the Assayunder Loratadine.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the capacity factor,k¢,is not less than 3.5;the tailing factor is not more than 1.7;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 15µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the peak response for the major peaks.Calculate the quantity,in mg,of loratadine (C22H23ClN2O2)in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Loratadine RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparation and the Standard preparation,respectively.