Indirect spectrophotometric determination of captopril in pharmaceutical tablets and spiked environmental samples

Abstract EN

A simple, accurate and sensitive indirect spectrophotometric method for the determination of captopril in pharmaceutical preparation (tablets) and environmental water samples has been developed.

The method is based on the oxidation of captopril by a known excess of potassium iodate (KIO3) in sulfuric acid medium to form iodide ion which reacts with excess iodate to liberate iodine which then reacts with starch to form a stable blue colored Iodine-starch complex which shows maximum absorbance at 606 nm.

Beers law was obeyed in the concentration range ( 2-28 ppm).

The molar absorptivity and Sandal's sensitivity of the colored complex are 1.716 x 104 l / mol.cm.

and 12.66 ng / cm2 respectively .The analytical parameters were optimized and the method was successfully applied to the determination of captopril in pure form, its tablets form and environmental water samples.