Neomycin and Polymyxin B Sulfates and Bacitracin Zinc Ophthalmic Ointment
» Neomycin and Polymyxin B Sulfates and Bacitracin Zinc Ophthalmic Ointment contains the equivalent of not less than 90.0 percent and not more than 140.0 percent of the labeled amounts of neomycin, polymyxin B, and bacitracin.
Packaging and storage—
Preserve in collapsible ophthalmic ointment tubes.
USP Reference standards 
11
—
11—
USP Bacitracin Zinc RS
USP Neomycin Sulfate RS
USP Polymyxin B Sulfate RS
Thin-layer chromatographic identification test 201BNP:
meets the requirements.
201BNP:
meets the requirements.
Sterility 71:
meets the requirements.
71:
meets the requirements.
Minimum fill 755:
meets the requirements.
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.
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—
It meets the requirements of the test for Metal Particles in Ophthalmic Ointments 751.
751.
Assay for neomycin—
Proceed as directed under Antibiotics—Microbial Assays 81, using an accurately weighed portion of Ophthalmic Ointment 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. 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.
81, using an accurately weighed portion of Ophthalmic Ointment 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. 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.
Assay for polymyxin B—
Proceed as directed 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 25-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 (10 Polymyxin B Units per mL). Add to each test dilution of the Standard a quantity of Neomycin Standard, dissolved in Buffer No. 6, to obtain the same concentration of neomycin present in the Test Dilution.
81, using an accurately weighed portion of Ophthalmic Ointment shaken with about 50 mL of ether in a separator, and extracted with four 25-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 (10 Polymyxin B Units per mL). Add to each test dilution of the Standard a quantity of Neomycin Standard, dissolved in Buffer No. 6, to obtain the same concentration of neomycin present in the Test Dilution.
Assay for bacitracin—
Proceed as directed 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 25-mL portions of 0.01 N hydrochloric acid. Combine the acid extracts, and dilute with 0.01 N hydrochloric acid to an appropriate volume to obtain a stock solution. Dilute this stock solution quantitatively and stepwise with Buffer No. 1 to obtain a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard (1.0 Bacitracin Unit per mL). [note—If the stock solution has a concentration of less than 100 Bacitracin Units per mL, add additional hydrochloric acid to each test dilution of the Standard to obtain the same concentration of hydrochloric acid as the Test Dilution. ]
81, using an accurately weighed portion of Ophthalmic Ointment shaken with about 50 mL of ether in a separator, and extracted with four 25-mL portions of 0.01 N hydrochloric acid. Combine the acid extracts, and dilute with 0.01 N hydrochloric acid to an appropriate volume to obtain a stock solution. Dilute this stock solution quantitatively and stepwise with Buffer No. 1 to obtain a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard (1.0 Bacitracin Unit per mL). [note—If the stock solution has a concentration of less than 100 Bacitracin Units per mL, add additional hydrochloric acid to each test dilution of the Standard to obtain the same concentration of hydrochloric acid as the Test Dilution. ]
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 |
|
| 71 |
Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison 1-301-816-8339 |
(GCM2010) General Chapters - Microbiology |
USP35–NF30 Page 4023
Pharmacopeial Forum: Volume No. 28(4) Page 1161