Medium: water;900mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Procedure— Determine the amount of C17H24BrNO3dissolved from UVabsorbances at the wavelength of maximum absorbance at about 258nm of 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 Homatropine Methylbromide RSin the same medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C17H24BrNO3is dissolved in 45minutes.

Procedure for content uniformity—

Standard preparation— Transfer about 25mg of USP Homatropine Methylbromide RS,accurately weighed,to a 50-mLvolumetric flask,add water to volume,and mix.Transfer 10.0mLof this solution to a second 50-mLvolumetric flask,dilute with water to volume,and mix.The concentration of USP Homatropine Methylbromide RSin the Standard preparationis about 100µg per mL.

Test preparation— Transfer 1finely powdered Tablet to a volumetric flask,suitably sized such that when the specimen is diluted to volume,the concentration is equivalent to about 100µg of homatropine methylbromide per mL.Add water to about one-half of the volume of the flask,shake for 10minutes,dilute with water to volume,mix,and filter,discarding the first 10mLof filtrate.Use the subsequent filtrate as directed in the Procedure.

Procedure— Transfer 2.0mLeach of the Standard preparationand the Test preparationto separate glass-stoppered,50-mLflasks.To each flask,add 0.1mLof sodium hydroxide solution (1in 10),and heat in a water bath at 80for 15minutes.Cool to room temperature,add 2.0mLof 0.2Mceric ammonium sulfate in 1Nsulfuric acid,and mix.To each flask,add 20.0mLof n-hexane,and shake for 15minutes.Decant the hexane layers into separate 1-cm cells,and concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 242nm,with a suitable spectrophotometer,using n-hexane as the blank.Calculate the quantity,in mg,of C17H24BrNO3in the Tablet by the formula: in which Tis the labeled quantity,in mg,of homatropine methylbromide in the Tablet,Cis the concentration,in µg per mL,of USP Homatropine Methylbromide RSin the Standard preparation,Dis the concentration,in µg per mL,of the Test preparation,based upon the labeled quantity per Tablet and the extent of dilution,and AUand ASare the absorbances of the solutions from the Test preparationand the Standard preparation,respectively.

Standard preparation— Transfer about 25mg of USP Homatropine Methylbromide RS,accurately weighed,to a 50-mLvolumetric flask,dissolve in water,dilute with water to volume,and mix.

Assay preparation— Weigh and finely powder not less than 20Tablets.Weigh accurately a portion of the powder,equivalent to about 12.5mg of homatropine methylbromide,and shake with 10mLof water at frequent intervals during 30minutes.Filter under reduced pressure through a sintered-glass crucible into a test tube placed in the suction flask under the filtering funnel,and wash under suction with several small portions of water.Transfer the contents of the test tube to a 25-mLvolumetric flask,dilute with water to volume,and mix.

Procedure— Transfer 10.0mLeach of the Standard preparationand the Assay preparationto separate test tubes,to each add 1mLof 5Nsulfuric acid and 2mLof ammonium reineckate TS,shake gently but well,and allow to stand for 1hour.Filter through a sintered-glass crucible with suction,using portions of the filtrate to transfer the precipitate completely to the filter,and wash it with three 2-mLportions of ice-cold water.Completely dissolve the precipitate by pouring over it 1-mLportions of acetone with the application of suction,receiving the solution in a 10-mLvolumetric flask,add acetone to volume,and mix.Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 525nm,with a suitable spectrophotometer,using acetone as the blank.Calculate the quantity,in mg,of C17H24BrNO3in the portion of Tablets taken by the formula: in which Cis the concentration,in µg per mL,of USP Homatropine Methylbromide RSin the Standard preparation;and AUand ASare the absorbances of the solutions from the Assay preparationand the Standard preparation,respectively.