U.S. PHARMACOPEIA

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Tetracycline Hydrochloride Ointment
» Tetracycline Hydrochloride Ointment contains not less than 90.0 percent and not more than 125.0 percent of the labeled amount of C22H24N2O8·HCl.
Packaging and storage— Preserve in well-closed containers, preferably at controlled room temperature.
Identification— The chromatogram of the Assay preparation obtained as directed in the Assay exhibits a major peak for tetracycline, the retention time of which corresponds to that exhibited in the chromatogram of the Standard preparation obtained as directed in the Assay.
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—
Diluting solvent , Mobile phase, Resolution solution, and Chromatographic system—Prepare as directed in the Assay under Tetracycline Hydrochloride.
Assay preparation— Transfer an accurately weighed portion of Ointment, equivalent to about 300 mg of tetracycline hydrochloride, to a glass-stoppered conical flask, add 20 mL of cyclohexane, and shake. Add 35 mL of methanol, and sonicate for about 20 minutes. Filter this solution into a 100-mL volumetric flask, and rinse the sides of the conical flask with 40 mL of methanol, filtering the rinsing through the filter into the volumetric flask. Dilute with methanol to volume, and mix. Transfer 2.0 mL of this solution to a 50-mL volumetric flask, dilute with Diluting solvent to volume, and mix.
Standard preparation— Dissolve an accurately weighed quantity of USP Tetracycline Hydrochloride RS quantitatively in methanol to obtain a solution having a known concentration of about 1 mg per mL. Transfer 6.0 mL of this solution to a 50-mL volumetric flask, dilute with Diluting solvent to volume, and mix. This solution contains about 0.12 mg of USP Tetracycline Hydrochloride RS per mL.
Procedure— Proceed as directed in the Assay under Tetracycline Hydrochloride. Calculate the quantity, in mg, of C22H24N2O8·HCl in the portion of Ointment taken by the formula:
2.5CP(rU / rS),
in which the terms are as defined therein.
Auxiliary Information— Staff Liaison : Brian D. Gilbert, Ph.D., Scientist
Expert Committee : (MDANT05) Monograph Development-Antibiotics
USP29–NF24 Page 2100
Phone Number : 1-301-816-8223