Methenamine Hippurate Tablets
»Methenamine Hippurate Tablets contain not less than 95.0percent and not more than 105.0percent of the labeled amount of methenamine hippurate (C6H12N4·C9H9NO3).
Packaging and storage— Preserve in well-closed containers.
Identification— Aportion of finely powdered Tablets responds to the Identificationtest under Methenamine Hippurate.
Dissolution á711ñ—
Medium: water;900mL.
Apparatus 2: 100rpm.
Time: 30minutes.
Standard solution— Dissolve an accurately weighed quantity of USP Methenamine Hippurate RSin water to obtain a solution having a known concentration of about 22µg per mL.
Procedure— Determine the amount of C6H12N4·C9H9NO3dissolved by employing UVabsorption,using a suitable spectrophotometer,at the wavelength of maximum absorbance at about 227nm on filtered portions of the solution under test,suitably diluted with water,if necessary,in comparison with the Standard solution.
Tolerances— Not less than 80%(Q)of the labeled amount of C6H12N4·C9H9NO3is dissolved in 30minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Assay— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 700mg of methenamine hippurate,to a 250-mLconical flask.Add 50mLof alcohol,then add thymolphthalein TS,and titrate with 0.1Nsodium hydroxide VS.Perform a blank determination on a mixture of 50mLof alcohol and 20mLof water,and make any necessary correction.Each mLof 0.1Nsodium hydroxide is equivalent to 31.94mg of methenamine hippurate (C6H12N4·C9H9NO3).
Auxiliary Information— Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 1242
Pharmacopeial Forum:Volume No.29(4)Page 1050
Phone Number:1-301-816-8394