A: Finely powder a number of Tablets, equivalent to about 90 mg of propantheline bromide, and triturate the powder with 10 mL of chloroform. Filter, and wash the filter with 10 mL of chloroform, collecting the filtrate and washing in a separator. Add 10 mL of water, shake, and discard the chloroform layer. Wash the aqueous layer with two 10-mL portions of ether, and discard the ether washings. Filter the aqueous solution, and evaporate on a steam bath with the aid of a current of dry air to dryness. Dissolve the residue in 5 mL of chloroform, mix, and proceed as directed in Identification test A under Propantheline Bromide, beginning with “In a well-ventilated hood”: the specified result is observed.

B: The chromatogram of the Assay preparation obtained as directed in the Assay exhibits a major peak for propantheline bromide, the retention time of which corresponds to that exhibited in the chromatogram of the Standard preparation.

Medium: pH 4.5 (±0.05) Acetate buffer prepared by mixing 1.64 g of anhydrous sodium acetate and 1.25 mL of glacial acetic acid with 500 mL of water, and diluting with water to obtain 1000 mL of solution having a pH of 4.50 ± 0.05; 500 mL.

Apparatus 2: 50 rpm.

Time: 45 minutes.

pH 3.5 buffer solution, Mobile phase, and Chromatographic system— Prepare as directed under Assay.

Procedure— Inject a volume (about 50 µL) of a filtered portion of the solution under test into the chromatograph, record the chromatogram, and measure the response for the major peak. Calculate the quantity of C23H30BrNO3 dissolved in comparison with a Standard solution having a known concentration of USP Propantheline Bromide RS in the same medium and similarly chromatographed.

Tolerances— Not less than 75% (Q) of the labeled amount of C23H30BrNO3 is dissolved in 45 minutes.

pH 3.5 buffer solution and Mobile phase— Prepare as directed for Related compounds under Propantheline Bromide.

Standard solution— Dissolve accurately weighed quantities of USP Propantheline Bromide Related Compound A RS, USP Xanthanoic Acid RS, and USP Xanthone RS in Mobile phase, and dilute quantitatively and stepwise if necessary, with Mobile phase to obtain a solution having known concentrations of about 12.0 µg of propantheline bromide related compound A per mL, and about 3.0 µg each of xanthanoic acid and xanthone per mL.

Test solution— Use the Assay preparation prepared as directed under Assay.

Chromatographic system (see Chromatography 621)— 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 2.0 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the resolution, R, between the least resolved peaks is not less than 1.2; and the relative standard deviation for replicate injections of the Standard solution is not more than 6.0% for each component or, if the Assay is performed concomitantly, the relative standard deviation for the propantheline bromide peak in the replicate injections of the Standard solution is not more than 2.0%.

Procedure— Separately inject equal volumes (about 50 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of xanthanoic acid, xanthone, and propantheline bromide related compound A greater than or equal to 0.1% in the portion of Tablets taken by the formula: in which C is the concentration, in µg, of xanthanoic acid, xanthone, or propantheline bromide related compound A per mL of the Standard solution; CX is the theoretical concentration, in µg per mL, of Propantheline Bromide in the Test solution; and rU and rS are the related compound peak responses obtained from the Test solution and the Standard solution, respectively: not more than 4.0% of propantheline bromide related compound A and 1.0% each of xanthone and xanthanoic acid are found.

pH 3.5 buffer solution and Mobile phase— Prepare as directed for Related compounds under Propantheline Bromide.

Standard preparation— Dissolve an accurately weighed quantity of USP Propantheline Bromide RS in Mobile phase to obtain a solution having a known concentration of about 0.3 mg per mL.

Assay preparation— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to 15 mg of propantheline bromide, to a 50-mL volumetric flask, dissolve in Mobile phase, dilute with Mobile phase to volume, mix, and filter.

Chromatographic system (see Chromatography 621)— 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 2.0 mL per minute. Chromatograph the Standard preparation, and record peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 50 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the peak responses. Calculate the quantity, in mg, of C23H30BrNO3 in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Propantheline Bromide RS in the Standard preparation; and rU and rS are the peak responses due to Propantheline Bromide obtained from the Assay preparation and the Standard preparation, respectively.