Tobramycin Ophthalmic Ointment
» Tobramycin Ophthalmic Ointment contains the equivalent of not less than 90.0 percent and not more than 120.0 percent of the labeled amount of tobramycin (C18H37N5O9).
Packaging and storage— Preserve in collapsible ophthalmic ointment tubes.
Identification— Vigorously shake by mechanical means a quantity of Ophthalmic Ointment, equivalent to about 3 mg of tobramycin, with 2 mL of chloroform. Add 1 mL of water, shake vigorously by mechanical means for 1 minute, and centrifuge for 15 minutes: the clear upper, aqueous layer so obtained meets the requirements of Identification test A under Tobramycin.
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.
Water, Method I 921: not more than 1.0%, 20 mL of a mixture of toluene and methanol (7:3) being used in place of methanol in the titration vessel.
Metal particles 751: meets the requirements.
Mobile phase, 2,4-Dinitrofluorobenzene reagent, Tris(hydroxymethyl)aminomethane reagent, Standard preparation, Resolution solution, and Chromatographic system— Proceed as directed in the Assay under Tobramycin.
Assay preparation— Transfer an accurately weighed portion of Ophthalmic Ointment, equivalent to about 4.5 mg of tobramycin, to a separator, add 50 mL of ether, and extract with four 20- to 25-mL portions of water. Combine the water extracts in a 100-mL volumetric flask, dilute with water to volume, and mix.
Derivatization procedure— Proceed as directed in the Assay under Tobramycin, except to use 15.0 mL of Assay preparation instead of 4.0 mL.
Procedure— Proceed as directed in the Assay under Tobramycin. Calculate the quantity of tobramycin (C18H37N5O9), in mg, in the portion of Ophthalmic Ointment taken by the formula:
(4 / 150)(CE)(rU / rS)
in which the terms are as defined therein.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Ahalya Wise, M.S.
(MDANT05) Monograph Development-Antibiotics
Reference Standards Lili Wang, Technical Services Scientist
71 Radhakrishna S Tirumalai, Ph.D.
Senior Scientist
(MSA05) Microbiology and Sterility Assurance
USP32–NF27 Page 3758
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.