Neomycin and Polymyxin B Sulfates, Bacitracin Zinc, and Lidocaine Ointment
» Neomycin and Polymyxin B Sulfates, Bacitracin Zinc, and Lidocaine Ointment contains the equivalent of not less than 90.0 percent and not more than 130.0 percent of the labeled amounts of neomycin, polymyxin B, and bacitracin, and not less than 90.0 percent and not more than 110.0 percent of the labeled amount of lidocaine (C14H22N2O).
Packaging and storage— Preserve in well-closed containers, preferably at controlled room temperature.
Identification—
A: It meets the requirements under Thin-Layer Chromatographic Identification Test 201BNP.
B: The retention time of the major peak for lidocaine in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay for lidocaine.
Minimum fill 755: meets the requirements.
Water, Method I 921: not more than 0.5%, 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 for neomycin under Neomycin and Polymyxin B Sulfates and Bacitracin Zinc Ophthalmic Ointment.
Assay for polymyxin B— Proceed with Ointment as directed in the Assay for polymyxin B under Neomycin and Polymyxin B Sulfates and Bacitracin Zinc Ophthalmic Ointment.
Assay for bacitracin— Proceed with Ointment as directed in the Assay for bacitracin under Neomycin and Polymyxin B Sulfates and Bacitracin Zinc Ophthalmic Ointment.
Assay for lidocaine—
Mobile phase, Standard preparation, and Chromatographic system— Proceed as directed in the Assay for lidocaine under Neomycin and Polymyxin B Sulfates, Bacitracin, and Lidocaine Ointment.
Assay preparation— Using the Ointment, proceed as directed for Assay preparation in the Assay for lidocaine under Neomycin and Polymyxin B Sulfates, Bacitracin, and Lidocaine Ointment.
Procedure— Proceed as directed for Procedure in the Assay for lidocaine under Neomycin and Polymyxin B Sulfates, Bacitracin, and Lidocaine Ointment. Calculate the quantity, in mg, of lidocaine (C14H22N2O) in the portion of Ointment taken by the formula:
100C(rU / rS)
in which C is the concentration, in mg per mL, of USP Lidocaine RS in the Standard preparation; and rU and rS are the lidocaine peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Ahalya Wise, M.S.
Scientist
1-301-816-8161		 (MDANT05) Monograph Development-Antibiotics
Reference Standards Lili Wang, Technical Services Scientist
1-301-816-8129
RSTech@usp.org
USP32–NF27 Page 3060
Pharmacopeial Forum: Volume No. 28(4) Page 1163