Pulse polarographic determination of isoniazid, hydralazine hydrochloride and dihydralazine sulphate based commercial hydrazine drugs

Isoniazid, Hydralazine hydrochloride and Dihydralazine sulphate are some commercial hydrazine-based drugs. This paper reports an investigation of the determination of these drugs in their commercial formulations for the purpose of quality control. A differential pulse polarographic (DPP) method based on the electrochemical reaction at dropping mercury electrode (DME) of drug dithiocarbazate derivative (formed from their reaction with carbon disulphide) yielding analytically useful waves and peaks at −1.10 V, -1.25 V and -0.94 V (vs SCE) respectively has been developed. The results have been calculated on the basis of a calibration graph drawn between drug concentration and wave current which were linear upto 40, 48 and 40 μg ml⁻¹ respectively of above drug compounds. The method has been extended to the analysis of some commercial drug formulations based on them. The recoveries of the drugs from pharmaceutical formulations were in the range 98.0–100.5% of the nominal content with RSDs in the range 0.23–1.94% indicating good accuracy and precision of the method.