Medium: water;500mL.

Apparatus 1: 100rpm.

Time: 45minutes.

Procedure— Determine the amount of C19H28BrNO3dissolved,employing the procedure set forth in the Assay,making any necessary modifications.

Tolerances— Not less than 75%(Q)of the labeled amount of C19H28BrNO3is dissolved in 45minutes.

pH5.3Phosphate buffer— Dissolve 38.0g of monobasic sodium phosphate and 2.0g of anhydrous dibasic sodium phosphate in sufficient water to make 1000mL,and adjust,if necessary,to a pHof 5.3±0.1.

Bromocresol purple solution— Dissolve 400mg of bromocresol purple in 30mLof alcohol,add 6.3mLof 0.1Nsodium hydroxide,and dilute with water to 500mL.

Buffer–dye mixture— On the day of use,mix equal volumes of pH5.3Phosphate bufferand of Bromocresol purple solution,and extract with chloroform until the last extract is colorless.

Standard preparation— Transfer about 100mg of USP Glycopyrrolate RS,accurately weighed,to a 100-mLvolumetric flask,add water to volume,and mix.Transfer 10.0mLof this solution to a second 100-mLvolumetric flask,dilute with water to volume,and mix to obtain a Standard preparationhaving a known concentration of about 100µg per mL.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 10mg of glycopyrrolate,to a 100-mLvolumetric flask,add 50mLof water,and shake by mechanical means for 10minutes.Dilute with water to volume,mix,and filter,discarding the first 20mLof the filtrate.Use the subsequent filtrate as directed in the Procedure.

Procedure— Transfer 10.0mLeach of the Standard preparation,the Assay preparation,and water to serve as the blank to individual separators,each containing 10.0mLof Buffer–dye mixture.Mix,and extract each solution with four 25-mLportions of chloroform,filtering the extracts from each solution through chloroform-moistened filter paper into separate 100-mLvolumetric flasks.Dilute each solution with chloroform to volume,and mix.Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 410nm,with a suitable spectrophotometer,using the blank to set the instrument.Calculate the quantity,in mg,of glycopyrrolate (C19H28BrNO3)in the portion of Tablets taken by the formula: in which Cis the concentration,in µg per mL,of USP Glycopyrrolate RSin the Standard preparation;and AUand ASare the absorbances of the solutions from the Assay preparationand the Standard preparation,respectively.