U.S. PHARMACOPEIA

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Methenamine Mandelate Tablets
» Methenamine Mandelate Tablets contain not less than 95.0 percent and not more than 105.0 percent of the labeled amount of methenamine mandelate (C6H12N4·C8H8O3).
Packaging and storage— Preserve in well-closed containers.
Identification, Infrared Absorption 197— Obtain the test specimen as follows. Triturate a quantity of finely powdered Tablets, equivalent to about 5.0 mg of methenamine mandelate, with 5 mL of chloroform, and pass through a 0.45-µm membrane filter. Evaporate the solvent, and allow the residue to air-dry.
Dissolution 711—
FOR UNCOATED OR PLAIN COATED TABLETS—
Medium: water; 900 mL.
Apparatus 1: 100 rpm.
Time: 45 minutes.
Procedure— Determine the amount of C6H12N4·C8H8O3 dissolved from UV absorbances at the wavelength of maximum absorbance at about 257 nm 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 RS in the same Medium.
Tolerances— Not less than 75% (Q) of the labeled amount of C6H12N4·C8H8O3 is dissolved in 45 minutes.
Uniformity of dosage units 905: meet the requirements.
Residual solvents 467: meet the requirements.
(Official January 1, 2007)
Assay— Weigh and finely powder not fewer than 20 Tablets. Weigh accurately a portion of the powder, equivalent to about 60 mg of methenamine mandelate, and transfer to a 250-mL conical flask. Proceed as directed in the Assay under Methenamine Mandelate, beginning with “Add 15 mL of dehydrated alcohol.”
Auxiliary Information— Staff Liaison : Behnam Davani, Ph.D., MBA, Senior Scientist
Expert Committee : (MDAA05) Monograph Development-Antivirals and Antimicrobials
USP29–NF24 Page 1377
Phone Number : 1-301-816-8394