Packaging and storage— Preserve in well-closed containers.

USP Reference standards 11— USP Oxytetracycline RS. USP Polymyxin B Sulfate RS.

Loss on drying 731— Dry about 100 mg, accurately weighed, of powdered Vaginal Inserts in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5 mm of mercury at 60 for 3 hours: it loses not more than 3.0% of its weight.

Residual solvents 467: meets the requirements.

Assay for oxytetracycline— Place not fewer than 5 Vaginal Inserts in a high-speed blender jar containing an accurately measured volume of 0.1 N hydrochloric acid, so that the stock solution obtained after blending for 3 to 5 minutes contains not less than 150 µg of oxytetracycline per mL. Proceed as directed for oxytetracycline under Antibiotics—Microbial Assays 81, using an accurately measured volume of this solution diluted quantitatively and stepwise with water to obtain a Test Dilution having a concentration of oxytetracycline assumed to be equal to the median dose level of the Standard.

Assay for polymyxin B— Weigh and finely powder not fewer than 5 Vaginal Inserts. Transfer an accurately weighed portion of the powder, equivalent to about 100,000 USP Polymyxin B Units, to a filter funnel equipped with a solvent-resistant membrane filter (1-µm or finer porosity). Wash the powder with five 20-mL portions of acetone, applying vacuum, and discarding the accumulated filtrate. [NOTE—If necessary, wash the powder with additional portions of acetone to remove any yellow color.] Carefully transfer the filter and the washed powder to a beaker containing about 400 mL of Buffer No. 6 (see Antibiotics—Microbial Assays 81), and stir. Transfer the contents of the beaker to a 500-mL volumetric flask with the aid of Buffer No. 6, dilute with the same solvent to volume, and mix. Proceed as directed for polymyxin B under Antibiotics—Microbial Assays 81, using an accurately measured volume of this solution diluted quantitatively and stepwise with Buffer No. 6 to yield a Test Dilution having a concentration of polymyxin B assumed to be equal to the median dose level of the Standard.

Expert Committee : (MDANT05) Monograph Development-Antibiotics

USP29–NF24 Page 1622

Phone Number : 1-301-816-8223