Uniformity of dosage units 
905
:
meets the requirements.
PROCEDURE FOR CONTENT UNIFORMITY—
Buffer solution, Mobile phase, Resolution solution, and Chromatographic system—
Proceed as directed in the
Assay under
Mesalamine.
Standard solution—
Transfer about 100 mg of
USP Mesalamine RS, accurately weighed, to a 50-mL volumetric flask, add 15 mL of 2 N hydrochloric acid, and dissolve by swirling. Dilute with 2 N hydrochloric acid to volume, and mix. Transfer 5.0 mL of this solution to a 25-mL volumetric flask, add 5 mL of 2 N sodium hydroxide, dilute with
Mobile phase to volume, and mix. Pass this solution through a suitable filter having a 0.5-µm or finer porosity.
Test solution—
Transfer, with the aid of 2 N hydrochloric acid, the contents of a container of Rectal Suspension to a 200-mL volumetric flask. Add 2 N hydrochloric acid to obtain about 160 mL of solution, and shake for about 10 minutes. Dilute with 2 N hydrochloric acid to volume, and mix. Transfer an accurately measured volume of this stock solution, equivalent to about 40 mg of mesalamine, to a 100-mL volumetric flask, add a volume of 2 N hydrochloric acid, equal to the added stock solution volume, dilute with Mobile phase to volume, and mix. Pass this solution through a suitable filter having a 0.5-µm or finer porosity.
Procedure—
Proceed as directed in the
Assay. Calculate the quantity, in g, of C
7H
7NO
3 in the container of Rectal Suspension taken by the formula:
20(C / V)(rU / rS),
in which
V is the volume, in mL, of stock solution taken to prepare the
Test solution; and the other terms are as defined therein.
Related compounds—
Test solution—
Transfer an accurately measured volume of Rectal Suspension, previously well shaken, equivalent to 100 mg of mesalamine, to a beaker, add water to give a volume of about 80 mL, adjust with phosphoric acid to a pH of 2.0, sonicate briefly to dissolve, transfer to a 100-mL volumetric flask, dilute with water to volume, and mix.
Procedure—
Proceed as directed in the test for
Related compounds under
Mesalamine. Calculate the percentage of each impurity in the Rectal Suspension taken by the formula:
0.1CM(ri / rSM),
in which the terms are as defined therein. Not more than 0.2% of any individual impurity is found; and not more than 1.0% of total impurities is found.
Content of sodium benzoate (if present)—
Mobile phase—
Transfer 390 mg of ammonium acetate to a 1000-mL volumetric flask, add 100 mL of water, and dissolve by swirling. Add 6 mL of glacial acetic acid and 300 mL of methanol, dilute with water to volume, and mix. Pass this solution through a filter having a 0.5-µm or finer porosity. Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard solution—
Transfer about 100 mg of sodium benzoate, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with water to volume, and mix. Transfer 5.0 mL of this solution to a second 100-mL volumetric flask, add 40 mL of methanol, dilute with water to volume, and mix. Pass this solution through a filter having a 0.5-µm or finer porosity.
Test solution—
Transfer about 5 g of well-shaken Rectal Suspension, accurately weighed, to a 100-mL volumetric flask, add 40 mL of methanol, dilute with water to volume, and mix. Pass this solution through a filter having a 0.5-µm or finer porosity.
Chromatographic system—
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 1.5 mL per minute. Inject the Standard solution into the chromatograph, and record the peak responses as directed for Procedure: the tailing factor is not more than 2.5; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 15 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 (w/w) of sodium benzoate in the Rectal Suspension taken by the formula:
10(C / W)(rU / rS),
in which
C is the concentration, in mg per mL, of sodium benzoate in the
Standard solution; W is the weight, in g, of the Rectal Suspension taken; and
rU and
rS are the responses obtained from the
Test solution and the
Standard solution, respectively: it contains between 0.05% and 0.125% of sodium benzoate.
Assay—
Buffer solution, Mobile phase, Resolution solution, Standard preparation, and Chromatographic system—
Proceed as directed in the
Assay under
Mesalamine.
Assay preparation—
Transfer an accurately measured, well-shaken quantity of Rectal Suspension, equivalent to about 100 mg of mesalamine, to a 100-mL volumetric flask, add 55 mL of Mobile phase, and dissolve by shaking for about 10 minutes. Dilute with Mobile phase to volume, and mix. Transfer 10.0 mL of this solution to a 25-mL volumetric flask, dilute with Mobile phase to volume, and mix. Pass this solution through a suitable filter having a 0.5-µm or finer porosity, and use the filtrate as the Assay preparation.
Procedure—
Proceed as directed in the
Assay under
Mesalamine. Calculate the quantity, in mg, of mesalamine (C
7H
7NO
3) in the portion of Rectal Suspension taken by the formula:
250C(rU / rS),
in which the terms are as defined therein.
