Packaging and storage—
Preserve in tight, light-resistant containers.
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.
Dissolution 
711
—
Medium:
water; 900 mL.
Apparatus 2:
75 rpm. Maintain a distance of 45 ± 5 mm between the blade and the inside bottom of the vessel.
Time:
60 minutes; 90 minutes for 500-mg capsules.
Procedure—
Determine the amount of C
22H
24N
2O
8·HCl dissolved from UV absorbances at the wavelength of maximum absorbance at about 276 nm of filtered portions of the solution under test, suitably diluted with
Dissolution Medium, if necessary, in comparison with a Standard solution having a known concentration of
USP Tetracycline Hydrochloride RS in the same
Medium.
Tolerances—
Not less than 80% (Q) of the labeled amount of C22H24N2O8·HCl is dissolved in 60 minutes; 90 minutes for 500-mg capsules.
Loss on drying 731—
Dry about 100 mg of Capsule contents, accurately weighed, in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5 mm of mercury at 60
for 3 hours: it loses not more than 4.0% of its weight.
Limit of 4-epianhydrotetracycline—
Using the
Diluting solvent,
Chromatographic system, and
Procedure set forth in the
Assay, chromatograph a Standard solution prepared by dissolving an accurately weighed quantity of
USP 4-Epianhydrotetracycline Hydrochloride RS in
Diluting solvent to obtain a solution having a known concentration of about 10 µg per mL. Using the chromatogram so obtained and the chromatogram of the
Assay preparation obtained as directed in the
Assay, calculate the percentage of 4-epianhydrotetracycline hydrochloride in the Capsules taken by the formula:
(10CE / T)(rU / rS),
in which
CE is the concentration, in µg per mL, of
USP 4-Epianhydrotetracycline Hydrochloride RS in the Standard solution;
T is the quantity, in mg, of tetracycline hydrochloride in the portion of Capsules taken to prepare the
Assay preparation, based on the labeled quantity; and
rU and
rS are the 4-epianhydrotetracycline peak responses obtained from the
Assay preparation and the Standard solution, respectively: not more than 3.0% is found.
Assay—
Diluting solvent, Mobile phase, Standard preparation, Resolution solution, and Chromatographic system—
Prepare as directed in the
Assay under
Tetracycline Hydrochloride.
Assay preparation—
Weigh accurately not fewer than 20 Capsules. Empty the Capsule contents into a mortar. Clean and accurately weigh the Capsule shells, and calculate the net weight of the Capsule contents. Mix the powder in the mortar, using a pestle, and transfer an accurately weighed quantity of the freshly mixed powder, equivalent to about 50 mg of tetracycline hydrochloride, to a 100-mL volumetric flask. Add about 50 mL of Diluting solvent, mix, and sonicate for about 5 minutes. Allow to cool, dilute with Diluting solvent to volume, mix, and filter.
Procedure—
Proceed as directed in the
Assay under
Tetracycline Hydrochloride. Calculate the quantity, in mg, of C
22H
24N
2O
8·HCl in the portion of Capsules taken by the formula:
(CP / 10)(rU / rS),
in which the terms are as defined therein.
