Neomycin and Polymyxin B Sulfates and Lidocaine Cream
» Neomycin and Polymyxin B Sulfates and Lidocaine Cream contains the equivalent of not less than 90.0 percent and not more than 130.0 percent of the labeled amounts of neomycin and polymyxin B, 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.
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Identification—
A:
It meets the requirements under Thin-Layer Chromatographic Identification Test 
201BNP
.
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.
755:
meets the requirements.
Assay for neomycin—
Proceed with Cream as directed in the Assay for neomycin under Neomycin and Polymyxin B Sulfates Cream.
Assay for polymyxin B—
Proceed with Cream as directed in the Assay for polymyxin B under Neomycin and Polymyxin B Sulfates Cream.
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 Cream, proceed as directed for the 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 Cream 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.
Senior Scientific Liaison 1-301-816-8161 |
(SM12010) Monographs - Small Molecules 1 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 4029
Pharmacopeial Forum: Volume No. 28(4) Page 1164