Liquid chromatographic determination of colchicine in pharmaceuticals: collaborative study

A liquid chromatographic (LC) method for the determination of colchicine in pharmaceutical dosage forms and the bulk drug was evaluated in an interlaboratory study which included 13 participating laboratories. The method involves extraction (or dissolution) of the active ingredient with methanol-water (1 + 1), followed by filtration of the extract and reverse phase LC using an octylsilane bonded phase column and UV detection at 254 nm. The mobile phase consists of a methanol-phosphate buffer mixture (pH = 5.5). Three commercial tablet formulations (0.5-0.6 mg colchicine/tablet), 1 synthetic injectable preparation (0.510 mg colchicine/mL), and 1 bulk drug sample were assayed in duplicate by the proposed method. The reproducibility and repeatability standard deviations based on nonpooled results for each sample ranged from 0.0062 mg/mL to 0.0147 mg/tablet and from 0.0037 mg/mL to 0.0127 mg/tablet, respectively; the corresponding coefficients of variation ranged from 1.21 to 2.54% and from 0.73 to 2.19%, respectively. The mean recovery from the synthetic injectable formulation was 100.0%. The method has been adopted official first action.