Identification—
The retention time of the major peak in the chromatogram of the
Assay preparation corresponds to that of the
Standard preparation obtained as directed in the
Assay.
Dissolution 
711
—
Medium:
water; 900 mL.
Apparatus 2:
50 rpm.
Time:
45 minutes.
Procedure—
Determine the amount of C
23H
27N
3O
7 dissolved from UV absorbances at the wavelength of maximum absorbance at about 348 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 Minocycline Hydrochloride RS in the same medium.
Tolerances—
Not less than 75% (Q) of the labeled amount of C23H27N3O7 is dissolved in 45 minutes.
Assay—
Mobile phase, Standard preparation, Resolution solution, and Chromatographic system—
Proceed as directed in the
Assay under
Minocycline Hydrochloride.
Assay preparation—
Weigh the contents of not less than 20 Capsules, and calculate the average weight per Capsule. Mix the combined contents of the Capsules, transfer an accurately weighed portion, equivalent to about 50 mg of minocycline (C23H27N3O7), to a 100-mL volumetric flask, add about 50 mL of water, and shake to dissolve. Dilute with water to volume, mix, and filter.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Minocycline Hydrochloride. Calculate the quantity, in mg, of minocycline (C
23H
27N
3O
7) in the portion of Capsules taken by the formula:
0.1C(rU / rS).
