Medium: 0.1Nhydrochloric acid;900mL.

Apparatus 2: 50rpm.

Time: 30minutes.

Buffer solution,Mobile phase,andChromatographic system— Proceed as directed in Assay.

Standard solution— Dissolve an accurately weighed quantity of USP Bethanechol Chloride RSin Dissolution Medium,and dilute quantitatively,and stepwise if necessary,with Dissolution Mediumto obtain a solution having a known concentration of USP Bethanechol Chloride RSapproximately corresponding to the concentration of the solution under test.

Procedure— Separately inject equal volumes (about 100µL)of a filtered portion of the solution under test and the Standard solutioninto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity of bethanechol chloride (C7H17ClN2O2)dissolved based on the peak responses obtained from the solution under test and the Standard solution.

Tolerances— Not less than 80%(Q)of the labeled amount of C7H17ClN2O2is dissolved in 30minutes.

Buffer solution— Transfer about 0.48g of methanesulfonic acid to a 1000-mLvolumetric flask.Dissolve in and dilute with water to volume.

Mobile phase— Prepare a filtered and degassed mixture of Buffer solutionand acetonitrile (95:5).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard solution— Dissolve an accurately weighed quantity of USP Bethanechol Chloride RSin Mobile phase,and dilute quantitatively and stepwise if necessary,with Mobile phaseto obtain a solution having a known concentration of about 1µg of USP Bethanechol Chloride RSper mL.

Test solution— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to 1Tablet,to a suitable volumetric flask so that the final solution yields a concentration of about 0.1mg per mLof bethanechol chloride.Add an amount of Mobile phase,about 60%to 70%of the total volume of the flask.Sonicate for 20minutes.Shake by mechanical means for about 15minutes.Dilute with Mobile phaseto volume,and mix.Allow to stand for 10minutes,and pass the solution through a 1-µm glass filter,discarding the first 3mLof the filtrate.

System suitability solution— Transfer about 25mg of bethanechol chloride,accurately weighed,to a 250-mLvolumetric flask.Add 10mLof 0.1Nsodium hydroxide,and allow to stand for about 15minutes.Add 10mLof 0.1Nhydrochloric acid.Dissolve in and dilute with Mobile phaseto volume,and mix.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a conductivity detector and a 3.9-×150-mm column containing packing L55.The flow rate is about 1.0mLper minute.The detector and column temperatures are maintained at 35and 30,respectively.Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the relative retention times are about 0.9for 2-hydroxypropyltrimethyl ammonium chloride and 1.0for bethanechol;and the resolution,R,between 2-hydroxypropyltrimethyl ammonium chloride and bethanechol is not less than 1.5.Chromatograph the Standard solution,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 10.0%for bethanechol chloride.

Procedure— Separately inject equal volumes (about 50µL)of the Standard solutionand Test solutioninto the chromatograph,record the chromatograms,and measure the responses for all of the peaks.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 Bethanechol Chloride RSin the Standard solution;Fis the relative response factor and is equal to 0.79for 2-hydroxypropyltrimethyl ammonium chloride and 1.0for any other impurity;riis the peak response for any impurity in the Test solution;rSis the peak response of USP Bethanechol Chloride RSin the Standard solution;and Wis the amount,in mg,of bethanechol chloride based on the average weight,labeled dose,and amount taken to prepare the Test solution.Not more than 1.0%of 2-hydroxypropyltrimethyl ammonium chloride is found;not more than 0.2%of any other impurity is found;and the sum of all the impurities is not more than 1.5%.

Buffer solution— Transfer about 29mg of edetate disodium to a 1000-mLvolumetric flask,and dissolve in 500mLof water.Add 300µLof nitric acid to the volumetric flask,and dilute with water to volume.Pass through a 0.45-µm nylon membrane filter.

Mobile phase— Prepare a filtered and degassed mixture of Buffer solutionand acetonitrile (95:5).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Bethanechol Chloride RSin Mobile phase,and dilute quantitatively,and stepwise if necessary,with Mobile phaseto obtain a solution having a known concentration of about 0.1mg of USP Bethanechol Chloride RSper mL.

Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to 1Tablet,to a suitable volumetric flask so that the final solution yields a concentration of about 0.1mg per mLof bethanechol chloride.Add an amount of Mobile phase,about 60%to 70%of the total volume of the flask.Sonicate for 20minutes.Shake by mechanical means for about 15minutes.Dilute with Mobile phaseto volume,and mix.Allow to stand for 10minutes,and pass the solution through a 1-µm glass filter,discarding the first 3mLof the filtrate.

System suitability solution— Transfer about 25mg of bethanechol chloride,accurately weighed,to a 250-mLvolumetric flask.Add 10mLof 0.1Nsodium hydroxide,and allow to stand for about 15minutes.Add 10mLof 0.1Nhydrochloric acid.Dissolve in and dilute with Mobile phaseto volume,and mix.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a conductivity detector and a 3.9-×150-mm column containing packing L55.The flow rate is about 1.0mLper minute.The detector and column temperatures are maintained at 35and 30,respectively.Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the relative retention time is about 0.9for 2-hydroxypropyltrimethyl ammonium chloride and 1.0for bethanechol;and the resolution,R,between 2-hydroxypropyltrimethyl ammonium chloride and bethanechol is not less than 1.5.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the tailing factor is not more than 3.5;and the relative standard deviation for replicate injections is not more than 3.0%.

Procedure— Separately inject equal volumes (about 50µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the peak responses.Calculate the quantity,in mg,of bethanechol chloride (C7H17ClN2O2)in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Bethanechol Chloride RSin the Standard preparation;Vis the volume,in mL,of the flask used to prepare the Assay preparation;and rUand rSare the bethanechol chloride peak responses obtained from the Assay preparationand the Standard preparation,respectively.