Two simple and sensitive spectrophotometric methods for the determination of indapamide
and co-dergocrine in pure form and in pharmaceutical preparations were developed. The
methods were based on the interaction of the cited drugs with either ammonium vanadate or
sodium nitrite in strongly acidic media. The resulting coloured products were measured at 530
and 550 nm for indapamide and co-dergocrine respectively. The effect of different variables on
the involved reactions and the colour development were studied and optimised. Beer,s law was
obeyed in the range of 1.8-12 g ml-1 for indapamide using ammonium vanadate and sodium
nitrite and 12-40 g ml-1 for co-dergocrine with both ammonium vanadate and sodium nitrite.
The reproducibility and recovery of the methods are excellent. The methods were applied
successfully to the determination of some commercially available dosage forms purchased from
the local market. The results were comparable to those obtained by official or reported
methods.