Gentamicin Sulfate Ointment
» Gentamicin Sulfate Ointment contains the equivalent of not less than 90.0 percent and not more than 135.0 percent of the labeled amount of gentamicin.
Packaging and storage— Preserve in collapsible tubes or other tight containers, and avoid exposure to excessive heat.
USP Reference standards 11
USP Gentamicin Sulfate RS Click to View Structure
Identification— Shake a quantity of Ointment, equivalent to about 5 mg of gentamicin, with a mixture of 200 mL of chloroform and 5 mL of water. Allow to separate, and filter the aqueous layer: the filtrate so obtained meets the requirements of the Identification test under Gentamicin Injection.
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 with Ointment as directed under Antibiotics—Microbial Assays 81, using an accurately weighed quantity of Ointment, equivalent to about 1 mg of gentamicin, shaken with about 50 mL of ether in a separator, and extracted with four 20-mL portions of Buffer No. 3. Combine the aqueous extracts, and dilute 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.
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
(SM12010) Monographs - Small Molecules 1
Reference Standards RS Technical Services
USP35–NF30 Page 3327