Oxytetracycline Hydrochloride and Polymyxin B Sulfate Vaginal Inserts
» Oxytetracycline Hydrochloride and Polymyxin B Sulfate Vaginal Inserts contain the equivalent of not less than 90.0 percent and not more than 120.0 percent of the labeled amounts of oxytetracycline (C22H24N2O9) and polymyxin B.
Packaging and storage Preserve in well-closed containers.
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.
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 AntibioticsMicrobial 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. [noteIf 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 AntibioticsMicrobial 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 AntibioticsMicrobial 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.
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USP32NF27 Page 3185Pharmacopeial Forum: Volume No. 29(3) Page 646