Amphotericin B Ointment
» Amphotericin B Ointment is Amphotericin B in a suitable ointment base. It contains not less than 90.0 percent and not more than 125.0 percent of the labeled amount of amphotericin B.
Packaging and storage Preserve in collapsible tubes, or other well-closed containers.
USP Reference standards 11
Minimum fill 755: meets the requirements.
Water, Method I 921: not more than 1.0%, 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 for amphotericin B under AntibioticsMicrobial Assays 81, using an accurately weighed portion of Ointment, equivalent to about 30 mg of amphotericin B, mixed with 10.0 mL of ether in a suitable glass-stoppered conical flask and allowed to stand, with intermittent shaking, for 1 hour. Add 20.0 mL of dimethyl sulfoxide and shake by mechanical means for 10 minutes. Dilute quantitatively and stepwise with dimethyl sulfoxide to a concentration of approximately 20 µg per mL. Quantitatively dilute an accurately measured volume of this stock solution with Buffer No. 10 to obtain a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.
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USP35NF30 Page 2207