Methscopolamine Bromide Tablets
» Methscopolamine Bromide Tablets contain not less than 93.0 percent and not more than 107.0 percent of the labeled amount of methscopolamine bromide (C18H24BrNO4).
Packaging and storage— Preserve in tight containers, and store at controlled room temperature.
USP Reference standards 11
USP Methscopolamine Bromide RS Click to View Structure
Identification—
A: Thin-Layer Chromatographic Identification Test 201
pH 7.3 Dye-buffer solution— Prepare a solution containing, in each 500 mL, 200 mg of bromothymol blue, 3.2 mL of 0.1 N sodium hydroxide, 577.5 mg of citric acid monohydrate, and 6.3 mg of anhydrous dibasic sodium phosphate.
Test solution— Finely powder 1 Tablet, and transfer an amount, equivalent to about 0.5 mg of methscopolamine bromide, to a suitable container. Add 20 mL of water, heat for 5 minutes on a steam bath with frequent agitation, and centrifuge to obtain a clear supernatant. Transfer 10 mL of the supernatant to a vessel containing 10 mL of chloroform and 10 mL of pH 7.3 Dye-buffer solution. Shake vigorously for 3 minutes, centrifuge, and transfer 8 mL of the chloroform layer to a suitable container. Evaporate to dryness, and dissolve the residue in 1 mL of chloroform.
Standard solution— Prepare a solution in water containing about 0.025 mg of USP Methscopolamine Bromide RS per mL, and treat as directed above, beginning with “Transfer 10 mL of the supernatant.”
Application volume: 50 µL.
Developing solvent system— In a suitable container, mix water, butyl alcohol, and glacial acetic acid (5:4:1), then transfer a measured volume of the upper organic layer to a suitable container, and mix with a volume of alcohol equivalent to 20% of the volume of the organic layer.
Procedure— Allow the solvent front to move about three-fourths of the length of the plate, remove the plate from the developing chamber, mark the solvent front, and dry the plate under a current of air for 30 minutes. Spray the plate evenly with potassium–bismuth iodide TS: the chromatogram of the Test solution shows a bright orange spot on a yellow background corresponding in RF value (about 0.25) to that in the chromatogram obtained from the Standard solution. [note—Bromothymol blue produces a dark yellow spot at an RF value of about 0.8. ]
B: Powder a number of Tablets, equivalent to about 5 mg of methscopolamine bromide, digest with 5 mL of water for 10 minutes, and filter: a portion of the clear solution so obtained responds to the test for Bromide 191.
Dissolution 711
Medium: 0.1 N hydrochloric acid; 500 mL.
Apparatus 2: 50 rpm.
Time: 30 minutes.
Determine the percentage of the labeled amount of methscopolamine bromide dissolved using the following method.
pH 3.0 Phosphate buffer— Dissolve 5.44 g of monobasic potassium phosphate in 1 L of water. Adjust with 1 N phosphoric acid to a pH of 3.0.
Mobile phase— Prepare a filtered and degassed mixture of pH 3.0 Phosphate buffer and methanol (3:1). Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard solution— Dissolve an accurately weighed quantity of USP Methscopolamine Bromide RS in Medium, and dilute quantitatively, and stepwise if necessary, with Medium to obtain a solution having a known concentration similar to the one expected in the Test solution.
Test solution— Use portions of the solution under test that have been passed through a 0.45-µm PTFE filter.
Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 204-nm detector and a 4.6-mm × 15-cm column that contains packing L1. The flow rate is about 1.0 mL per minute. The column temperature is maintained at 30. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure— Separately inject equal volumes (about 25 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 methscopolamine bromide dissolved by the formula:
Click to View Image
in which rU and rS are the peak responses obtained from the Test solution and the Standard solution, respectively; CS is the concentration, in mg per mL, of USP Methscopolamine Bromide RS in the Standard solution; 500 is the volume, in mL, of Medium; 100 is the factor for conversion to percentage; and LC is the tablet label claim, in mg.
Tolerances— Not less than 80% (Q) of the labeled amount of C18H24BrNO4 is dissolved in 30 minutes.
Uniformity of dosage units 905: meet the requirements.
Assay—
Mobile phase— Prepare a solution containing 2.6 g of decyl sodium sulfate in 450 mL of water. Add 550 mL of methanol, adjust with 1 N sulfuric acid to a pH of 3.5, mix, filter, and degas.
Standard preparation— Transfer about 25 mg of USP Methscopolamine Bromide RS, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix.
Assay preparation—
for tablets that contain 2.5 mg of methscopolamine bromide— Place 10 Tablets in a 100-mL volumetric flask, add about 50 mL of Mobile phase, and sonicate for 30 minutes. Shake by mechanical means for 30 minutes, dilute with Mobile phase to volume, and mix. Pass a portion through a 0.45-µm PTFE filter, discarding the first 2 to 3 mL of the filtrate.
for tablets that contain 5 mg of methscopolamine bromide— Place 10 Tablets in a 200-mL volumetric flask, add about 100 mL of Mobile phase, and sonicate for 30 minutes. Shake by mechanical means for 30 minutes, dilute with Mobile phase to volume, and mix. Pass a portion through a 0.45-µm PTFE filter, discarding the first 2 to 3 mL of the filtrate.
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 L1. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 2.0%.
Procedure— Separately inject a volume (about 50 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatogram, and measure the peak responses. Calculate the quantity, in mg, of methscopolamine bromide (C18H24BrNO4) in the portion of Tablets taken by the formula:
100C(rU / rS)
in which C is the concentration, in mg per mL, of USP Methscopolamine Bromide RS in the Standard preparation; and rU and rS are the peak responses of the methscopolamine bromide obtained from the Assay preparation and the Standard preparation, respectively.
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