ANALYSIS OF ISONIAZID USING 2-METHYL-3-NITROPYRIDINE-6-CARBOXALDEHYDE

The developed procedure is based on the interaction of isoniazid with 2-methyi-3-nitropyridine-6-carboxaldehyde at room temperature. The colour intensity of the reaction product was quantified spectrophotometrically at 385 nm with a lower limit of detection of 0.5 μg/ml. The colour is stable for at least 24 hours. There is no interference from congenial drugs, common carbohydrates and excipients used as additives in solid pharmaceutical formulations of isoniazid. The main degradation products of isoniazid do not interfere in the assay. The developed method can be recommended as a selective stability indicating assay. © 1979.