Meclocycline Sulfosalicylate Cream
» Meclocycline Sulfosalicylate Cream contains the equivalent of not less than 90.0 percent and not more than 125.0 percent of the labeled amount of meclocycline (C22H21ClN2O8).
Packaging and storage Preserve in tight containers, protected from light.
USP Reference standards 11
Minimum fill 755: meets the requirements.
0.001 M Ammonium edetate Transfer 293 mg of edetic acid, accurately weighed, to a 1000-mL volumetric flask, add 1 mL of methanol and 7 mL of ammonium hydroxide, and shake to dissolve the edetic acid. Add 900 mL of water, adjust with glacial acetic acid to a pH of 6.6, dilute with water to volume, and mix.
Mobile phase Prepare a mixture of 0.001 M Ammonium edetate and tetrahydrofuran (85 : 15). Filter and degas the solution before use.
Standard stock preparation Dissolve an accurately weighed quantity of USP Meclocycline Sulfosalicylate RS in methanol to obtain a solution having a known concentration of about 0.5 mg of meclocycline per mL.
Standard preparation Immediately prior to injection, dilute the Standard stock preparation quantitatively, and stepwise if necessary, with Mobile phase, to obtain a solution having a known concentration of about 10 µg of meclocycline per mL.
Assay stock preparation Transfer an accurately weighed quantity of Cream, equivalent to about 5 mg of meclocycline, to a glass-stoppered, 50-mL centrifuge tube. Add 20 mL of methanol and 20 mL of 0.025 N sulfuric acid, and shake vigorously for 15 minutes. Transfer the solution to a 50-mL volumetric flask, rinse the centrifuge tube with two 5-mL portions of methanol, and add the rinsings to the flask. Dilute with methanol to volume, and mix.
Assay preparation Centrifuge a portion of the Assay stock preparation for 5 minutes. Immediately prior to injection, transfer 5 mL of the supernatant to a 50-mL volumetric flask, dilute with Mobile phase to volume, mix, and filter to obtain a solution having a nominal concentration of about 10 µg of meclocycline per mL.
Chromatographic system The liquid chromatograph is equipped with a 340-nm detector and a 4-mm × 25-cm column that contains packing L1. The flow rate is about 0.8 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative standard deviation of the meclocyline peak for replicate injections is not more than 3.0%.
Procedure Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the meclocycline peak. Calculate the percent label claim of C22H21ClN2O8 in the portion of Cream taken by the formula:
(CS / CU)(rU / rS)(100)in which CS is the concentration, in µg per mL, of meclocycline in the Standard preparation; CU is the nominal concentration, in µg per mL, of meclocycline in the Assay preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 3778Pharmacopeial Forum: Volume No. 34(3) Page 628