Spectrophotometric Determination of Diazepam in Pure form, Tablets and Ampoules

The interaction of diazepam with picric acid (I), 3,5-dinitrobenzoic acid (II) and 2,4-dinitrobenzoic acid (III) was found to be useful for its spectrophotometric determination. The quantitation was carried out at 475, 500, and 500 nm for the reaction with (I), (II) and (III), respectively. The effect of several variables on the coloring process was studied. The proposed methods have been applied successfully for the determination of diazepam in pure samples and in its pharmaceutical preparations with good accuracy and precision. The results were compared to those obtained by the pharmacopoeial methods. The linear ranges for obedience of Beer's law are up to 85.6, 180.2, and 128.6 µg/ml, Ringbom ranges are 10.0-79.0, 15.2-177.8, 17.0-83.0 µg/ml, and RSD 0.048, 0.028, and 0.026% for reaction of diazepam with I, II, and III, respectively.