Neomycin Sulfate and Fluorometholone Ointment
» Neomycin Sulfate and Fluorometholone 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 amount of fluorometholone (C22H29FO4).
Packaging and storage— Preserve in collapsible tubes or in well-closed containers.
USP Reference standards 11
USP Fluorometholone RS Click to View Structure
USP Neomycin Sulfate RS
Identification—
A: It meets the requirements for neomycin under Thin-Layer Chromatographic Identification Test 201BNP.
B: The ratios of the retention time of the main peak to that of the internal standard peak obtained from the Standard preparation and the Assay preparation as directed in the Assay for fluorometholone do not differ by more than 2.0%.
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.
Assay for neomycin— Proceed with Ointment as directed in the Assay under Neomycin Sulfate Ointment.
Assay for fluorometholone—
Internal standard solution, Mobile solvent, and Standard preparation— Prepare as directed in the Assay under Fluorometholone Cream.
Assay preparation— Transfer an accurately weighed quantity of Ointment, equivalent to about 1 mg of fluorometholone, to a suitable container, add 20.0 mL of Internal standard solution, and mix.
Procedure— Treat 20.0 mL each of the Standard preparation and the Assay preparation in the following manner. To each add 10.0 mL of hexane, shake for about 15 minutes, then allow the layers to separate, and centrifuge, if necessary. Using the lower (acetonitrile) layer, proceed as directed for Procedure in the Assay under Fluorometholone Cream, beginning with “Using a suitable microsyringe.” Calculate the quantity, in mg, of C22H29FO4 in the portion of Ointment taken by the formula:
20C(RU / RS)
in which the terms are as defined therein.
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Topic/Question Contact Expert Committee
Monograph Ahalya Wise, M.S.
Senior Scientific Liaison
1-301-816-8161
(SM12010) Monographs - Small Molecules 1
Reference Standards RS Technical Services
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USP35–NF30 Page 4014
Pharmacopeial Forum: Volume No. 28(4) Page 1155