Identification—
To an accurately measured volume of Oral Suspension, equivalent to about 50 mg of methacycline, add 50 mL of methanol, shake, and allow the mixture to settle. Using the clear supernatant as the
Test Solution, proceed as directed for
Method II under
Identification—Tetracyclines 
193
.
Assay—
Mobile phase, System suitability preparation, and Chromatographic system—
Proceed as directed in the Assay under Methacycline Hydrochloride.
Assay preparation—
Transfer an accurately measured quantity of Oral Suspension, freshly mixed and free from air bubbles, equivalent to about 50 mg of methacycline (C
22H
22N
2O
8), to a 100-mL volumetric flask, dilute with
Mobile phase to volume, mix, and filter.
Procedure—
Proceed as directed in the
Assay under
Methacycline Hydrochloride. Calculate the quantity, in mg, of methacycline (C
22H
22N
2O
8) in each mL of the Oral Suspension taken by the formula:
100(CE / 1000V)(rU / rS),
in which
V is the volume, in mL, of Oral Suspension taken to prepare the
Assay preparation; and the other terms are as defined therein.
Methacycline Hydrochloride Oral Suspension contains the equivalent of not less than 90.0 percent and not more than 125.0 percent of the labeled amount of methacycline (C22H22N2O8). It contains one or more suitable and harmless buffers, colors, diluents, dispersants, flavors, and preservatives.