» Griseofulvin Tablets contain not less than 90.0 percent and not more than 115.0 percent of the labeled amount of griseofulvin (C17H17ClO6).
Packaging and storage Preserve in tight containers.
Labeling The label indicates that the griseofulvin contained is known as griseofulvin (microsize).
USP Reference standards 11
Identification The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Medium: water containing 40.0 mg of sodium lauryl sulfate per mL; 1000 mL.
Apparatus 2: 75 rpm.
Time: 90 minutes.
Procedure Determine the amount of C17H17ClO6 dissolved from UV absorbances at the wavelength of maximum absorbance at about 291 nm of filtered portions of the solution under test, suitably diluted with a solution of methanol and water (4:1), if necessary, in comparison with a Standard solution having a known concentration of USP Griseofulvin RS in the same medium.
Tolerances Not less than 75% (Q) of the labeled amount of C17H17ClO6 is dissolved in 90 minutes.
Uniformity of dosage units 905: meet the requirements.
Procedure for content uniformity Transfer 1 Tablet to a suitable container, add an accurately measured volume of methanol sufficient to yield a concentration of griseofulvin not greater than 1 mg per mL, shake by mechanical means for 1 hour, or longer if necessary to disperse the specimen completely, and sonicate for 1 minute. Centrifuge a portion of this solution, and quantitatively dilute an accurately measured volume of the clear supernatant to obtain a test solution containing about 10 µg of griseofulvin per mL. Concomitantly determine the absorbances of the test solution and a Standard solution of USP Griseofulvin RS in methanol having a known concentration of about 10 µg per mL at the wavelength of maximum absorbance at about 292 nm, with a suitable spectrophotometer, using methanol as the blank. Calculate the quantity, in mg, of griseofulvin (C17H17ClO6) in the Tablet taken by the formula:
(CL / D)(AU / AS)in which C is the concentration, in µg per mL, of USP Griseofulvin RS in the Standard solution; L is the labeled quantity, in mg, of griseofulvin in the Tablet; D is the concentration, in µg per mL, of griseofulvin in the test solution, based on the labeled quantity per Tablet and the extent of dilution; and AU and AS are the absorbances of the test solution and the Standard solution, respectively.
Loss on drying 731 Dry about 100 mg of finely ground Tablets, accurately weighed, in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5 mm of mercury at 60 for 3 hours: it loses not more than 5.0% of its weight.
Mobile phase, Standard preparation, and Chromatographic system Proceed as directed in the Assay under Griseofulvin.
Assay preparation Weigh and finely powder not fewer than 20 Tablets, and proceed as directed for Assay preparation in the Assay under Griseofulvin Capsules, beginning with transfer an accurately weighed portion.
Procedure Proceed as directed for Procedure in the Assay under Griseofulvin. Calculate the quantity, in mg, of griseofulvin (C17H17ClO6) in the portion of Tablets taken by the formula:
PC(rU / rS)in which C is the concentration, in mg per mL, of USP Griseofulvin RS in the Standard preparation, and the other terms are as defined therein.
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USP35NF30 Page 3379