Packaging and storage—
Preserve in tight, light-resistant containers.
Identification—
Shake a suitable quantity of Capsule contents with methanol to obtain a solution containing 1 mg of oxytetracycline per mL, and filter. Using the filtrate as the
Test Solution, proceed as directed for
Method II under
Identification—Tetracyclines 
193
.
Dissolution 711—
Medium:
water; 900 mL.
Apparatus 2:
75 rpm.
Time:
60 minutes.
Procedure—
Determine the amount of C
22H
24N
2O
9 dissolved from UV absorbances at the wavelength of maximum absorbance at about 273 nm of filtered portions of the solution under test, suitably diluted with water, in comparison with a Standard solution having a known concentration of
USP Oxytetracycline RS in the same medium, using 5 mL of 0.1 N hydrochloric acid to dissolve the Standard.
Tolerances—
Not less than 80% (Q) of the labeled amount of C22H24N2O9 is dissolved in 60 minutes.
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 5.0% of its weight.
Assay—
Tetrabutylammonium hydrogen sulfate solution
,
Edetate disodium solution,
pH 7.5 Phosphate buffer,
Mobile phase,
Standard preparation, Resolution solution, and
Chromatographic system—Proceed as directed in the
Assay under
Oxytetracycline.
Assay preparation—
Remove, as completely as possible, the contents of not less than 20 Capsules, and mix. Transfer an accurately weighed portion of the powder, equivalent to about 100 mg of oxytetracycline, to a 500-mL volumetric flask, add about 50 mL of 0.01 N hydrochloric acid, and swirl to dissolve. Dilute with 0.01 N hydrochloric acid to volume, mix, and filter a portion of the solution through a 0.5-µm or finer porosity filter. Use the filtrate as the Assay preparation.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Oxytetracycline. Calculate the quantity, in mg, of oxytetracycline (C
22H
24N
2O
9) in the portion of Capsules taken by the formula:
0.5(CP)(rU / rS),
in which the terms are as defined therein.
