Identification—
Pulverize a quantity of Tablets, equivalent to about 100 mg of bethanechol chloride, add 15 mL of ether, and allow to digest for 15 minutes. Decant the ether, again extract the residue with 10 mL of ether, and discard the ether extracts. To the residue add 30 mL of alcohol, shake for 10 minutes, and allow to stand for 1 hour with frequent agitation. Filter with suction, and evaporate the filtrate on a steam bath to dryness: the bethanechol chloride so obtained, recrystallized from alcohol and dried at 105
for 2 hours, responds to
Identification test
A under
Bethanechol Chloride.
Dissolution 
711
—
Medium:
0.1 N hydrochloric acid; 900 mL.
Apparatus 2:
50 rpm.
Time:
30 minutes.
Determine the amount of bethanechol chloride (C7H17ClN2O2) dissolved using the following method.
Buffer solution, Mobile phase, and Chromatographic system—
Proceed as directed in Assay.
Standard solution—
Dissolve an accurately weighed quantity of
USP Bethanechol Chloride RS in
Medium, and dilute quantitatively, and stepwise if necessary, with
Medium to obtain a solution having a known concentration of
USP Bethanechol Chloride RS approximately corresponding to the concentration of the solution under test.
Procedure—
Separately inject equal volumes (about 100 µL) of a filtered portion of the solution under test and the Standard solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity of bethanechol chloride (C7H17ClN2O2) dissolved based on the peak responses obtained from the solution under test and the Standard solution.
Tolerances—
Not less than 80% (Q) of the labeled amount of C7H17ClN2O2 is dissolved in 30 minutes.
Related compounds—
Buffer solution—
Transfer about 0.48 g of methanesulfonic acid to a 1000-mL volumetric flask. Dissolve in and dilute with water to volume.
Mobile phase—
Prepare a filtered and degassed mixture of
Buffer solution and acetonitrile (95:5). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard solution—
Dissolve an accurately weighed quantity of
USP Bethanechol Chloride RS in
Mobile phase, and dilute quantitatively and stepwise if necessary, with
Mobile phase to obtain a solution having a known concentration of about 1 µg of
USP Bethanechol Chloride RS per mL.
Test solution—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to 1 Tablet, to a suitable volumetric flask so that the final solution yields a concentration of about 0.1 mg per mL of bethanechol chloride. Add an amount of Mobile phase, about 60% to 70% of the total volume of the flask. Sonicate for 20 minutes. Shake by mechanical means for about 15 minutes. Dilute with Mobile phase to volume, and mix. Allow to stand for 10 minutes, and pass the solution through a 1-µm glass filter, discarding the first 3 mL of the filtrate.
System suitability solution—
Transfer about 25 mg of bethanechol chloride, accurately weighed, to a 250-mL volumetric flask. Add 10 mL of 0.1 N sodium hydroxide, and allow to stand for about 15 minutes. Add 10 mL of 0.1 N hydrochloric acid. Dissolve in and dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a conductivity detector and a 3.9- × 150-mm column containing packing L55. The flow rate is about 1.0 mL per minute. The detector and column temperatures are maintained at 35
and 30
, respectively. Chromatograph the
System suitability solution, and record the peak responses as directed for
Procedure: the relative retention times are about 0.9 for 2-hydroxypropyltrimethyl ammonium chloride and 1.0 for bethanechol; and the resolution,
R, between 2-hydroxypropyltrimethyl ammonium chloride and bethanechol is not less than 0.8. Chromatograph the
Standard solution, and record the peak responses as directed for
Procedure: the relative standard deviation for replicate injections is not more than 10.0% for bethanechol chloride.
Procedure—
Separately inject equal volumes (about 50 µL) of the
Standard solution and
Test solution into the chromatograph, record the chromatograms, and measure the responses for all of the peaks. Calculate the percentage of each impurity in the portion of Tablets taken by the formula:
100V(F/W)C(ri / rS),
in which
C is the concentration, in mg per mL, of
USP Bethanechol Chloride RS in the
Standard solution; F is the relative response factor and is equal to 0.79 for 2-hydroxypropyltrimethyl ammonium chloride and 1.0 for any other impurity;
ri is the peak response for any impurity in the
Test solution; rS is the peak response of
USP Bethanechol Chloride RS in the
Standard solution; and
W is the amount, in mg, of bethanechol chloride based on the average weight, labeled dose, and amount taken to prepare the
Test solution. Not more than 1.0% of 2-hydroxypropyltrimethyl ammonium chloride is found; not more than 0.2% of any other impurity is found; and the sum of all the impurities is not more than 1.5%.
Assay—
Buffer solution—
Transfer about 29 mg of edetic acid to a 1000-mL volumetric flask, and dissolve in 500 mL of water. Add 300 µL of nitric acid to the volumetric flask, and dilute with water to volume. Pass through a 0.45-µm nylon membrane filter.
Mobile phase—
Prepare a filtered and degassed mixture of
Buffer solution and acetonitrile (95:5). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation—
Dissolve an accurately weighed quantity of
USP Bethanechol Chloride RS in
Mobile phase, and dilute quantitatively, and stepwise if necessary, with
Mobile phase to obtain a solution having a known concentration of about 0.1 mg of
USP Bethanechol Chloride RS per mL.
Assay preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to 1 Tablet, to a suitable volumetric flask so that the final solution yields a concentration of about 0.1 mg per mL of bethanechol chloride. Add an amount of Mobile phase, about 60% to 70% of the total volume of the flask. Sonicate for 20 minutes. Shake by mechanical means for about 15 minutes. Dilute with Mobile phase to volume, and mix. Allow to stand for 10 minutes, and pass the solution through a 1-µm glass filter, discarding the first 3 mL of the filtrate.
System suitability solution—
Transfer about 25 mg of bethanechol chloride, accurately weighed, to a 250-mL volumetric flask. Add 10 mL of 0.1 N sodium hydroxide, and allow to stand for about 15 minutes. Add 10 mL of 0.1 N hydrochloric acid. Dissolve in and dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a conductivity detector and a 3.9- × 150-mm column containing packing L55. The flow rate is about 1.0 mL per minute. The detector and column temperatures are maintained at 35
and 30
, respectively. Chromatograph the
System suitability solution, and record the peak responses as directed for
Procedure: the relative retention time is about 0.9 for 2-hydroxypropyltrimethyl ammonium chloride and 1.0 for bethanechol; and the resolution,
R, between 2-hydroxypropyltrimethyl ammonium chloride and bethanechol is not less than 0.8. Chromatograph the
Standard preparation, and record the peak responses as directed for
Procedure: the tailing factor is not more than 3.5; and the relative standard deviation for replicate injections is not more than 3.0%.
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 bethanechol chloride (C
7H
17ClN
2O
2) in the portion of Tablets taken by the formula:
VC(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Bethanechol Chloride RS in the
Standard preparation; V is the volume, in mL, of the flask used to prepare the
Assay preparation; and
rU and
rS are the bethanechol chloride peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
