Packaging and storage— Preserve in tight containers.

USP Reference standards 11— USP Methenamine Mandelate RS.

Identification— Triturate a quantity, equivalent to about 100 mg of methenamine mandelate, with 10 mL of chloroform, and pass through a 0.45-µm membrane filter. Evaporate the solvent, wash the residue with 5 small portions of ether, and allow it to air-dry: the IR absorption spectrum of a potassium bromide dispersion of the residue so obtained exhibits maxima only at the same wavelengths as that of a potassium bromide dispersion of USP Methenamine Mandelate RS.

Uniformity of dosage units 905—

Deliverable volume 698—

Water, Method I 921: not more than 0.1%.

Residual solvents 467: meets the requirements.

Assay— Shake the Oral Suspension, then pipet, using a “to contain” pipet, an amount equivalent to 1 g of methenamine mandelate, into a 100-mL volumetric flask. Add 5.0 mL of dehydrated alcohol, mix, and add methylene chloride to volume. Pipet 5 mL of this solution into a 250-mL conical flask. Add 15 mL of dehydrated alcohol, and proceed as directed in the Assay under Methenamine Mandelate, beginning with “add 40 mL of chloroform.”

Expert Committee : (MDAA05) Monograph Development-Antivirals and Antimicrobials

USP29–NF24 Page 1377

Phone Number : 1-301-816-8394