Novel Reagents for the Spectrophotometric Determination of Isoniazid in Pure and Pharmaceutical Formulations

New, simple and cost effective spectrophotometric methods have been developed for the quality assessment of isoniazid (INH), in bulk and in pharmaceutical formulations by using novel reagents. The proposed methods involve the utility of ethyl 2-[(E)-(4hydroxyphenyl) diazenyl]-3-oxobutanoate and benzil as novel reagents for the determination of INH. Developed methods are based on the condensation reaction of INH with reagents to give orange colored chromogen with an absorption band at 454 nm (for method A) and 436 nm (for method B). The applicability of these methods is demonstrated by the determination of the studied drug in commercial tablets and the results are statistically evaluated. The new procedures described in this paper are fast, convenient and have the novelty of carrying out the quantitative determination of INH in pure and in pharmaceutical formulation.