RESUMO
Simple, accurate and sensitive colorimetric and fluorimetric methods are described for the determination of the choleretic drug azintamide. The colorimetric methods are based on thionine formation, a blue colored compound, absorbing maximally at 600 nm. Thionine is formed by heating acidic azintamide solution with zinc powder in presence of p-phenylenediamine and then addition of iron [3] ammonium sulfate solution. The fluorimetric method is based on measurement of the previously formed thionine after extraction with n-butanol at 550 and 620 nm excitation and emission wave lengths, respectively. The colorimetric and fluorimetric methods were applicable over the concentration ranges of 50-250 and 10-50 ug ml-1, respectively. These methods were further applied for analysis of azintamide in pharmaceutical preparations and the results were in agreement with those obtained from direct UV spectrophotometric method