A: Transfer a volume of Injection, equivalent to about 2 mg of colchicine, to a separator. Add 5 mL of water, and extract with 15 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.

B: The UV absorption spectrum of the Injection, diluted with water to a concentration of about 10 µg of colchicine per mL, exhibits maxima and minima at the same wavelengths as that of a similar solution of USP Colchicine RS, concomitantly measured.

Mobile phase, Standard preparation, and Chromatographic system— Prepare as directed in the Assay under Colchicine.

Assay preparation— [note—Prepare immediately before use.] Transfer an accurately measured volume, V mL, of Injection, equivalent to about 1 mg of colchicine, to a 50-mL volumetric flask, dilute with a mixture of methanol and water (1:1) to volume, and mix. Pipet 30 mL of this solution into a 100-mL volumetric flask, dilute with the same mixture to volume, and mix.

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 each mL of the Injection taken by the formula: 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.