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Neomycin Sulfate, Sulfacetamide Sodium, and Prednisolone Acetate Ophthalmic Ointment
» Neomycin Sulfate, Sulfacetamide Sodium, and Prednisolone Acetate Ophthalmic Ointment contains the equivalent of not less than 90.0 percent and not more than 135.0 percent of the labeled amount of neomycin, and not less than 90.0 percent and not more than 110.0 percent of the labeled amounts of sulfacetamide sodium (C8H9N2NaO3S·H2O) and prednisolone acetate (C23H30O6).
Packaging and storage— Preserve in collapsible ophthalmic ointment tubes.
Identification—
A: Dissolve a quantity of Ophthalmic Ointment, equivalent to about 1 g of sulfacetamide sodium, in 100 mL of ether in a separator, and extract the mixture with 25 mL of water. Wash the extract with 25 mL of ether, and warm the water extract on a steam bath to remove the last traces of ether. Adjust with 6 N acetic acid to a pH of between 4 and 5, and filter. Wash the precipitate with water, and dry at 105 for 2 hours: the sulfacetamide so obtained melts between 180 and 184, and responds to Identification tests B, D, and E under Sulfacetamide Sodium.
B: To a quantity of Ophthalmic Ointment, equivalent to about 25 mg of prednisolone acetate, add 15 mL of water, extract with two 10-mL portions of peroxide-free ether, discard the ether extracts, and extract with two 10-mL portions of chloroform. Evaporate the combined, clear chloroform extracts, with the aid of a current of air, to dryness: the residue so obtained responds to Identification test A under Prednisolone Acetate.
Sterility 71— It meets the requirements when tested as directed for Membrane Filtration under Test for Sterility of the Product to be Examined.
Minimum fill 755: meets the requirements.
Metal particles— It meets the requirements of the test for Metal Particles in Ophthalmic Ointments 751.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay for neomycin— Proceed with Ophthalmic Ointment as directed in the Assay under Neomycin Sulfate Ointment.
Assay for sulfacetamide sodium— Weigh accurately a quantity of Ophthalmic Ointment, equivalent to about 500 mg of sulfacetamide sodium, and transfer to a 125-mL separator. Dissolve the ointment in 50 mL of ether, and extract the mixture with six 25-mL portions of water. Warm the combined extracts on a steam bath to remove the last traces of ether, add 20 mL of hydrochloric acid, and proceed as directed under Nitrite Titration 451, beginning with “cool to 15.” Each mL of 0.1 M sodium nitrite is equivalent to 25.42 mg of C8H9N2NaO3S·H2O.
Assay for prednisolone acetate—
Standard preparation— Prepare as directed for Standard Preparation under Assay for Steroids 351, using USP Prednisolone Acetate RS.
Assay preparation— Transfer to a suitable flask an accurately weighed quantity of Ophthalmic Ointment, equivalent to about 10 mg of prednisolone acetate, and add 30 mL of alcohol. Heat on a steam bath to melt the ointment base, and mix. Cool to solidify the ointment base, and filter the alcohol solution into a 100-mL volumetric flask. Repeat the extraction with three 20-mL portions of alcohol, add alcohol to volume, and mix. Pipet 10 mL of this solution into a 100-mL volumetric flask, add alcohol to volume, and mix. Pipet 20 mL of the resulting solution into a glass-stoppered, 50-mL conical flask.
Procedure— Proceed as directed for Procedure under Assay for Steroids 351. Calculate the quantity, in mg, of C23H30O6 in the portion of Ophthalmic Ointment taken by the formula:
C(AU / AS).
Auxiliary Information— Staff Liaison : Brian D. Gilbert, Ph.D., Scientist
Expert Committee : (MDANT05) Monograph Development-Antibiotics
USP29–NF24 Page 1515
Phone Number : 1-301-816-8223