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
—
[NOTE—Conduct 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 C
22H
25NO
6 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.
Assay—
[NOTE—Perform all dilutions in low-actinic glassware.
]
Mobile phase, Standard preparation, and Chromatographic system—
Prepare as directed in the
Assay under
Colchicine.
Assay preparation—
[NOTE—Prepare 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 C
22H
25NO
6 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.
