Packaging and storage
Preserve in tight,light-resistant containers.
Identification
The chromatogram of the
Assay preparationobtained as directed in the
Assayexhibits a major peak for tetracycline,the retention time of which corresponds to that exhibited in the chromatogram of the
Standard preparationobtained as directed in the
Assay.
Dissolution á711ñ
Medium:
water;900mL.
Apparatus 2:
75rpm.Maintain a distance of 45±5mm between the blade and the inside bottom of the vessel.
Time:
60minutes;90minutes for 500-mg capsules.
Procedure
Determine the amount of C
22H
24N
2O
8·HCl dissolved from UVabsorbances at the wavelength of maximum absorbance at about 276nm 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 RSin the same
Medium.
Tolerances
Not less than 80%(Q)of the labeled amount of C22H24N2O8·HCl is dissolved in 60minutes;90minutes for 500-mg capsules.
Loss on drying á731ñ
Dry about 100mg of Capsule contents,accurately weighed,in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5mm of mercury at 60

for 3hours:it loses not more than 4.0%of its weight.
Limit of 4-epianhydrotetracycline
Using the
Diluting solvent,
Chromatographic system,and
Procedureset forth in the
Assay,chromatograph a Standard solution prepared by dissolving an accurately weighed quantity of
USP4-Epianhydrotetracycline Hydrochloride RSin
Diluting solventto obtain a solution having a known concentration of about 10µg per mL.Using the chromatogram so obtained and the chromatogram of the
Assay preparationobtained 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
CEis the concentration,in µg per mL,of
USP4-Epianhydrotetracycline Hydrochloride RSin the Standard solution;
Tis the quantity,in mg,of tetracycline hydrochloride in the portion of Capsules taken to prepare the
Assay preparation,based on the labeled quantity;and
rUand
rSare the 4-epianhydrotetracycline peak responses obtained from the
Assay preparationand 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
Assayunder
Tetracycline Hydrochloride.
Assay preparation
Weigh accurately not fewer than 20Capsules.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 50mg of tetracycline hydrochloride,to a 100-mLvolumetric flask.Add about 50mLof Diluting solvent,mix,and sonicate for about 5minutes.Allow to cool,dilute with Diluting solventto volume,mix,and filter.
Procedure
Proceed as directed in the
Assayunder
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.