Neomycin Sulfate and Gramicidin Ointment, chemical structure, molecular formula, Reference Standards

Neomycin Sulfate and Gramicidin Ointment

»Neomycin Sulfate and Gramicidin Ointment contains the equivalent of not less than 90.0percent and not more than 140.0percent of the labeled amounts of neomycin and gramicidin.

Packaging and storage— Preserve in collapsible tubes or in well-closed containers.

USP Reference standards á11ñ— USP Gramicidin RS.USP Neomycin Sulfate RS.

Thin-Layer Chromatographic Identification Test á201BNPñ: meets the requirements.

Minimum fill á755ñ: meets the requirements.

Water,Method Iá921ñ: not more than 1.0%,20mLof 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 theAssay underNeomycin Sulfate Ointment.

Assay for gramicidin— Proceed as directed for gramicidin underAntibiotics—Microbial Assays á81ñ,using an accurately weighed portion of Ointment dissolved in 50mLof hexanes in a separator,and extracted with four 20-mLportions of 80percent 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 aTest Dilution having a concentration of gramicidin assumed to be equal to the median dose level of the Standard.

Auxiliary Information— Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow

Expert Committee:(PA7)Pharmaceutical Analysis 7

USP28–NF23Page 1347

Pharmacopeial Forum:Volume No.28(4)Page 1156

Phone Number:1-301-816-8335