Spectrophotometric determination of captopril in pharmaceutical preparations

ABSTRACT

Two simple and sensitive spectrophotometric methods for the estimation of captopril were presented. The first was based on the formation of stable charge-transfer complex between iodine monochloride [ICl], as sigma-acceptor, and captopril; Beer's law was obeyed in the concentration range 2-12 mug.ml -1. The second method involved the formation of a stable high colored radical anion of chloranilic acid [CA], as pi-acceptor, upon reaction with captopril; Beer's law was obeyed in the concentration range 0.4-8 mug.ml -1. The optimum experimental conditions in each case were determined. The proposed procedures have been successfully applied to the determination of captopril tablets and the results obtained showed a good agreement with those obtained by the official methods: