Packaging and storage—
Preserve in well-closed containers.
Identification,Infrared Absorption á197ñ—
Obtain the test specimen as follows.Triturate a quantity of finely powdered Tablets,equivalent to about 5.0mg of methenamine mandelate,with 5mLof chloroform,and pass through a 0.45-µm membrane filter.Evaporate the solvent,and allow the residue to air-dry.
Dissolution á711ñ—
FOR UNCOATED OR PLAIN COATED TABLETS—
Medium:
water;900mL.
Apparatus 1:
100rpm.
Time:
45minutes.
Procedure—
Determine the amount of C
6H
12N
4·C
8H
8O
3dissolved from UVabsorbances at the wavelength of maximum absorbance at about 257nm of portions of the solution under test,filtered through a 0.45-µm filter and suitably diluted with
Medium,if necessary,in comparison with a Standard solution having a known concentration of
USP Methenamine Mandelate RSin the same
Medium.
Tolerances—
Not less than 75%(Q)of the labeled amount of C6H12N4·C8H8O3is dissolved in 45minutes.
Assay—
Weigh and finely powder not fewer than 20Tablets.Weigh accurately a portion of the powder,equivalent to about 60mg of methenamine mandelate,and transfer to a 250-mLconical flask.Proceed as directed in the
Assayunder
Methenamine Mandelate,beginning with “Add 15mLof dehydrated alcohol.”