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

Abstract

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. Beer,s law was obeyed in the concentration range ( 2-28 ppm).
The molar absorptivity and Sandell,s sensitivity of the colored complex are
1.716x104 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.