Spectrophotometric determination of colchicine using iron(III) chloride and 1,10-phenanthroline

A new spectrophotometric method for the quantitative determination of colchicine in pure and its pharmaceutical formulations has been developed. The method involves the oxidation of colchicine by iron(III) chloride and subsequent complexation of iron(II) with 1,10-phenanthroline forming a red coloured complex having maximum absorbance at 510 nm. Beer's law holds well in the concentration range 5-50 mug ml(-1). The common excipients do not interfere with the proposed method. The results of the proposed method are in good agreement with the reported method and show no significant difference in the precision.