Simple and Rapid Methods for the Analysis of Captopril in Dosage Forms

Two indirect methods are described for the micro determination of captopril using hexacyanoferrate (III) as reagent. The reaction used for titrimetry proceeds at room temperature and will be complete in 10 minute with a stoichiometry of 1:1 with respect to the oxidant and captopril. The reaction product used for spectrophotometric determination shows the absorption maximum at 510 nm. The Beer's law is obeyed over the concentration range 0.25-12.00 μg mL -1 , the molar absorptivity and Sandell sensitivity for the system being 9.14◊10 3 L mol -1 cm -1 and 23.78 ng cm -2 , respectively. The limit of detection and quantification are found to be 0.08 and 0.26 μg mL -1 , respectively. Both procedures have been applied to the determination of captopril in tablets. The results have been statistically compared with those obtained by the official (BP) method.