U.S. PHARMACOPEIA

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Oxytetracycline Hydrochloride and Hydrocortisone Ointment
» Oxytetracycline Hydrochloride and Hydrocortisone Ointment contains the equivalent of not less than 90.0 percent and not more than 115.0 percent of the labeled amount of oxytetracycline (C22H24N2O9), and not less than 90.0 percent and not more than 110.0 percent of the labeled amount of hydrocortisone.
Packaging and storage— Preserve in collapsible tubes or in well-closed, light-resistant containers.
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.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay for oxytetracycline— Transfer a suitable, accurately weighed quantity of Ointment to a separator, add 50 mL of ether, and shake. Add 20 mL of 0.1 N hydrochloric acid, shake, and allow to separate. Collect the acid layer, and repeat the extraction with three additional 20-mL portions of 0.1 N hydrochloric acid. Combine the acid extracts in a 100-mL volumetric flask, dilute with 0.1 N hydrochloric acid to volume, and mix. Quantitatively dilute a portion of this solution with 0.1 N hydrochloric acid so that the solution so obtained contains not less than 150 µg of oxytetracycline per mL. Proceed as directed for oxytetracycline under Antibiotics—Microbial Assays 81, using an accurately measured volume of this solution diluted quantitatively and stepwise with water to yield a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.
Assay for hydrocortisone— Proceed with Ointment as directed in the Assay for hydrocortisone under Neomycin and Polymyxin B Sulfate, Bacitracin Zinc, and Hydrocortisone Ophthalmic Ointment.
Auxiliary Information— Staff Liaison : Brian D. Gilbert, Ph.D., Scientist
Expert Committee : (MDANT05) Monograph Development-Antibiotics
USP29–NF24 Page 1620
Phone Number : 1-301-816-8223