Spectrophotometric Determination of Isoniazid Using Ethyl 8-Quinolinoxy Acetate

Abstract
A colorimetric method based on the interaction of isoniazid and the newly synthesized ethyl 8-quinolinoxy acetate (2) was developed. The absorbance was measured at 504 nm and the procedure was found to be sensitive for INH in the 10−4 M range. The method was applied to the analysis of the drug in pharmaceutical dosage forms and proved to be simple, demonstrating good accuracy and precision. Structural elucidation of the reagent 2 as well as the chromogen 4 has been achieved using 1H NMR and elemental analyses.