Spectrophotometric Determination of Carbamazepine Via Oxidative Coupling Reaction with 2,4-dinitrophenyl hydrazine

An accurate and sensitive spectrophotometric method has been developed for thedetermination of carbamazepine (CRN.) in pure and dosage forms. The method is based onthe oxidation of 2,4-dinitrophenylhydrazine (2,4-DNPHz) by potassium periodate thancoupling with carbamazepine (CRN.) in alkaline medium to form a stable yellowish browncolored water-soluble dye with a maximum absorption at 485 nm. The variables that affect thecompletion of reaction have been carefully optimized. Beer’s law is obeyed over theconcentration range of (4-50 μg.mL-1) with molar absorptivity of (6.7335×103 L.mol-1.cm-1). The limit of detection was (0.1052 μg.mL-1) and Sandell’s sensitivity value was 0.0350μg.cm-2.The proposed method has been applied successfully to the determination ofcarbamazepine in pharmaceutical preparation.