» Colchicine Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C22H25NO6.
Packaging and storage Preserve in well-closed, light-resistant containers.
USP Reference standards 11
USP Colchicine RS
Identification Weigh a portion of ground Tablets, equivalent to about 20 mg of colchicine, triturate with 20 mL of water, allow the solids to settle, and filter the supernatant into a separator. Extract with 30 mL of chloroform. Evaporate the chloroform extract, using mild heat, to dryness: the IR absorption spectrum of a potassium bromide dispersion of the residue so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Colchicine RS.
Dissolution, Procedure for a Pooled Sample 711 [noteConduct this procedure without delay, under subdued light, and using low-actinic glassware. ]
Medium: water; 500 mL.
Apparatus 1: 100 rpm.
Time: 30 minutes.
Procedure Determine the amount of C22H25NO6 dissolved, employing the procedure set forth in the Assay under Colchicine, making any necessary modifications.
Tolerances Not less than 75% (Q) of the labeled amount of C22H25NO6 is dissolved in 30 minutes.
Uniformity of dosage units 905: meet the requirements.
Assay [notePerform all dilutions in low-actinic glassware. ]
Mobile phase, Standard preparation, and Chromatographic system Prepare as directed in the Assay under Colchicine.
Assay preparation [notePrepare immediately before use. ] Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 0.6 mg of colchicine, to a 100-mL volumetric flask, add about 50 mL of a mixture of methanol and water (1:1), and shake by mechanical means for 15 minutes, rinsing down the walls of the flask at about 8 minutes. Dilute with the same mixture to volume, and pass through a 0.45-µm membrane filter.
Procedure Proceed as directed for Procedure in the Assay under Colchicine, and measure the responses for the colchicine peaks. Calculate the quantity, in mg, of C22H25NO6 in the portion of Tablets taken by the formula:
0.1C(rU / rS)in which C is the concentration, in µg per mL, of the Standard 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 2764Pharmacopeial Forum: Volume No. 30(1) Page 91