A: Prepare 3mLof a solution in chloroform having a concentration of about 6mg per mL,and reserve a 1-mLportion for Identificationtest B.In a well-ventilated hood,apply 2mLof this solution dropwise to a salt plate while continuously evaporating the solvent with the aid of an IRheat lamp and a current of dry air.Heat the residue at 105for 15minutes:the IRabsorption spectrum of the residue on the single salt plate exhibits maxima only at the same wavelengths as that of a similar preparation of USP Propantheline Bromide RS,treated in the same manner.

B: Apply 5µLof the chloroform solution retained from Identificationtest Aand 5µLof a Standard solution of USP Propantheline Bromide RSin chloroform containing 6mg per mLto a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel.Develop the chromatogram in a solvent system consisting of a mixture of 1Nhydrochloric acid and acetone (1:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and dry at 105for 5minutes.Spray the plate with potassium-bismuth iodide TS,and heat at 105for 5minutes:the RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.

C: To 5mLof a solution (1in 100)add 2mLof 2Nnitric acid:this solution responds to the tests for Bromide á191ñ,except that in the test that liberates bromine,the chloroform layer may be yellow.

pH3.5buffer solution— Dissolve 17.3g of sodium dodecyl sulfate in 1000mLof water containing 10mLof phosphoric acid in a 2000-mLvolumetric flask.Add 250mLof 0.5Msodium hydroxide and,while stirring,adjust with 0.5Msodium hydroxide or dilute phosphoric acid (1in 10)to a pHof 3.5±0.05,dilute with water to volume,and mix.

Mobile phase— Prepare a filtered and degassed mixture of acetonitrile andpH3.5buffer solution(55:45).Make adjustments if necessary (seeSystem SuitabilityunderChromatography á621ñ).

Standard solution— Dissolve accurately weighed quantities of USP Propantheline Bromide Related Compound A RS,USP Xanthanoic Acid RS,and USP Xanthone RSinMobile phase,and dilute quantitatively,and stepwise if necessary,withMobile phaseto obtain a solution having a known concentration of about 6.0µg of propantheline bromide related compound Aper mL,and about 1.5µg each of xanthanoic acid and xanthone per mL.

Test solution— Transfer about 60mg of Propantheline Bromide,accurately weighed,to a 200-mLvolumetric flask,dissolve inMobile phase,dilute withMobile phaseto volume,and mix.

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 L7.The flow rate is about 2.0mLper minute.Chromatograph theStandard solution,and record peak responses as directed forProcedure:the resolution,R,between the least resolved peaks is not less than 1.2;and the relative standard deviation for replicate injections of theStandard solutionis not more than 6.0%for each component.

Procedure— Separately inject equal volumes (about 50µL)of theStandard solutionand theTest solutioninto the chromatograph,record the chromatograms for a total time of not less than 1.5times the retention time of the propantheline bromide peak,and measure the response for each peak,except the peaks at or before the void volume.Calculate the percentage of xanthanoic acid,xanthone,and propantheline bromide related compound Agreater than or equal to 0.1%in the portion of Propantheline Bromide taken by the formula: in whichCis the concentration,in µg,of xanthanoic acid,xanthone,or propantheline bromide related compound Aper mLof theStandard solution;Wis the weight,in mg,of Propantheline Bromide taken;andrUandrSare the related compound peak responses obtained from theTest solutionand theStandard solution,respectively:not more than 2.0%of propantheline bromide related compound Aand 0.5%each of xanthone and xanthanoic acid is found.Calculate the percentage of all unknown impurities greater than or equal to 0.1%by the formula: in whichriis the response of the unknown impurity peak;andrtis the sum of the responses of all the measured peaks observed in the chromatogram:the sum total of all known and unknown impurities is not more than 3.0%.