Bacitracin Zinc and Polymyxin B Sulfate Ophthalmic Ointment
» Bacitracin Zinc and Polymyxin B Sulfate Ophthalmic Ointment contains the equivalent of not less than 90.0 percent and not more than 130.0 percent of the labeled amounts of bacitracin and polymyxin B.
Packaging and storage— Preserve in collapsible ophthalmic ointment tubes.
Thin-layer chromatographic identification test 201BNP: meets the requirements.
Sterility 71 It meets the requirements when tested as directed for Membrane Filtration under Test for Sterility of the Product to be Examined.
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.
Metal particles 751: meets the requirements.
Assay for bacitracin— Proceed with Ophthalmic Ointment as directed in the Assay under Bacitracin Zinc Ointment.
Assay for polymyxin B— Proceed as directed for polymyxin B under Antibiotics—Microbial Assays 81, using an accurately weighed portion of Ophthalmic Ointment shaken with about 50 mL of ether in a separator and extracted with four 20-mL portions of Buffer No. 6. Combine the aqueous extracts, and dilute with Buffer No. 6 to an appropriate volume to obtain a stock solution. Dilute this stock solution quantitatively and stepwise with Buffer No. 6 to obtain a Test Dilution having a concentration 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
71 Radhakrishna S Tirumalai, Ph.D.
Senior Scientist
(MSA05) Microbiology and Sterility Assurance
USP32–NF27 Page 1625
Pharmacopeial Forum: Volume No. 28(4) Page 1071