Neomycin Sulfate and Gramicidin Ointment
» Neomycin Sulfate and Gramicidin Ointment contains the equivalent of not less than 90.0 percent and not more than 140.0 percent of the labeled amounts of neomycin and gramicidin.
Packaging and storage— Preserve in collapsible tubes or in well-closed containers.
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 for neomycin— Proceed with Ointment as directed in the Assay under Neomycin Sulfate Ointment.
Assay for gramicidin— Proceed as directed for gramicidin under Antibiotics—Microbial Assays 81, using an accurately weighed portion of Ointment dissolved in 50 mL of hexanes in a separator, and extracted with four 20-mL portions of 80 percent alcohol. Combine the extracts in a suitable volumetric flask, dilute with alcohol to volume, and mix. Dilute this solution quantitatively and stepwise with alcohol to obtain a Test Dilution having a concentration of gramicidin 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 3051
Pharmacopeial Forum: Volume No. 28(4) Page 1156