A new method for spectrophotometric determination of colchicoside

Abstract

A facile spectrophotometric method is proposed for determination of Colchicoside (COLSID) in bulk and in dosage forms using ceric ammonium sulphate (CAS). Method involves addition of a known excess of CAS to COLSID and determination of residual CAS with a fixed amount of either Azure B (AB), measuring absorbance at 633nm or Safranin O (SO), measuring absorbance at 519 nm. Calibration graphs are linear over 25.00-50.00 μgml^-1, 22.00-38.00 μgml^-1 and apparent molar absorptivity is calculated to be 2.28 x 10⁴ l mol^-1 cm^-1 and 2.77 x 10⁴ l mol^-1 cm^-1 for CAS-AB and CAS-SO respectively. Method is successfully applied to assay of COLSID in pharmaceutical formulations.