Bacitracin Zinc Ointment
» Bacitracin Zinc Ointment is Bacitracin Zinc in an anhydrous ointment base. It contains not less than 90.0 percent and not more than 140.0 percent of the labeled amount of bacitracin.
Packaging and storage Preserve in well-closed containers containing not more than 60 g, unless labeled solely for hospital use, preferably at controlled room temperature.
Thin-layer chromatographic identification test 201BNP: meets the requirements.
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 Proceed as directed under AntibioticsMicrobial Assays 81, using an accurately weighed portion of Ointment shaken with about 50 mL of ether in a separator, and extracted with four 20-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, adding additional hydrochloric acid to each test dilution of the Standard to obtain the same concentration of hydrochloric acid as in the Test Dilution.
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USP32NF27 Page 1624Pharmacopeial Forum: Volume No. 28(4) Page 1071