UTILITY OF CERTAIN PI-ACCEPTORS FOR THE SPECTROPHOTOMETRIC DETERMINATION OF ISONIAZID

The interaction of isoniazid with three selected 1T-acceptors in an aqueous-acetonitrile solution of pH 9.G-9.5 was found to give intensely coloured products. A spectrophotometric method based on this reaction is described for quantitation of isoniazid. The determination of products was carried out at 445 nm for chloranil, 450 nm for bromanil and around 750 nm for 7, 7, 8, 8-tetracyanoquinodimethane. The effect of several variables on the colour development was studied. The molecular ratios of the reactants have been established. The proposed methods have been applied successfully for analysis of isoniazid in pure samples and in a number of its pharmaceutical preparations with good accuracy and precision. Results were compared to those obtained by the official methods. © 1990, Taylor & Francis Group, LLC. All rights reserved.