Identification—
To an accurately measured volume of Oral Suspension,equivalent to about 50mg of doxycycline,add 50mLof methanol,shake,and allow to settle.Using the clear supernatant as the
Test Solution,proceed as directed for
Method IIunder
Identification—Tetracyclines á193ñ.
Assay—
Mobile phase,Resolution solution,Standard preparation,andChromatographic system—
Proceed as directed in the
Assayunder
Doxycycline Hyclate.
Edetate diluent—
Transfer 5.2g of edetate disodium to a 500-mLvolumetric flask,add about 400mLof Mobile phase,sonicate for about 10minutes or until dissolved,dilute with Mobile phaseto volume,and mix.
Assay preparation—
Constitute Oral Suspension as directed in the labeling.Transfer an accurately measured portion of the constituted oral suspension,freshly mixed and free from air bubbles,equivalent to about 100mg of doxycycline,to a 100-mLvolumetric flask,add 50mLof Edetate diluent,sonicate for 15minutes,and then shake by mechanical means for about 15minutes.Dilute with Edetate diluentto volume,and mix.Pass through filter paper,discarding the first 10mLof the filtrate,then pass through a filter having a 0.5-µm or finer porosity.
Procedure—
Proceed as directed for
Procedurein the
Assayunder
Doxycycline Hyclate.Calculate the quantity,in mg,of doxycycline (C
22H
24N
2O
8)in each mLof the Oral Suspension taken by the formula:
0.1(CP/V)(rU/rS),
in which
Vis the volume,in mL,of Oral Suspension taken to prepare the
Assay preparation;and the other terms are as defined therein.