Neomycin Sulfate Ointment
» Neomycin Sulfate Ointment contains the equivalent of not less than 90.0 percent and not more than 135.0 percent of the labeled amount of neomycin.
Packaging and storage— Preserve in well-closed containers, preferably at controlled room temperature.
Thin-layer chromatographic identification test 201BNP: meets the requirements.
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— Proceed as directed under AntibioticsMicrobial Assays 81, using an accurately weighed portion of Ointment, equivalent to about 3.5 mg of neomycin, shaken in a separator with about 50 mL of ether, and extracted with four 20-mL portions of Buffer No. 3. Combine the aqueous extracts, and dilute with Buffer No. 3 to an appropriate volume to obtain a stock solution of convenient concentration. Dilute this stock solution quantitatively and stepwise with Buffer No. 3 to obtain a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.
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
USP32–NF27 Page 3046
Pharmacopeial Forum: Volume No. 28(4) Page 1152