Clindamycin Phosphate Vaginal Cream
»Clindamycin Phosphate Vaginal Cream contains an amount of Clindamycin Phosphate equivalent to not less than 90.0percent and not more than 110.0percent of the labeled amount of clindamycin (C18H33ClN2O5S).
Packaging and storage— Preserve in well-closed containers.
Identification— The chromatogram of the Assay preparationobtained as directed in the Assayexhibits a major peak for clindamycin phosphate,the retention time of which corresponds to that in the chromatogram of the Standard preparationas obtained in the Assay.
pHá791ñ: between 3.0and 6.0,determined on the undiluted Cream.
Assay—
Mobile phase ,Resolution solution,Standard preparation,and Chromatographic system—Proceed as directed in the Assayunder Clindamycin Phosphate Gel.
Assay preparation— Transfer an accurately weighed quantity of Cream,equivalent to about 20mg of clindamycin (C18H33ClN2O5S),to a 125-mLconical flask,add 100.0mLof Mobile phaseand about 10glass beads (about 10mm in diameter).Insert the stopper in the flask securely,and shake by mechanical means at 50for about 1hour.Cool in an ice bath for about 20minutes,and centrifuge.Filter a few mLof the cloudy lower layer through a filter of 2µm or finer porosity,and use the filtrate as the Assay preparation.
Procedure— Proceed as directed for Procedurein the Assayunder Clindamycin Phosphate Gel.Calculate the quantity,in mg,of clindamycin (C18H33ClN2O5S)in the portion of Cream taken by the formula:
0.1CE(rU/rS),
in which the terms are as defined therein.
Auxiliary Information— Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 496
Phone Number:1-301-816-8335
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