Packaging and storage— Preserve in well-closed containers, preferably at controlled room temperature.

USP Reference standards 11— USP Neomycin Sulfate RS.

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.

Residual solvents 467: meets the requirements.

Assay— Proceed as directed under Antibiotics—Microbial 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.

Expert Committee : (MDANT05) Monograph Development-Antibiotics

USP29–NF24 Page 1492

Phone Number : 1-301-816-8223