4- Dinitro phenylhydrazine

A spectroscopic method has been proposed for the determination of two phenolic drugs; Phenylephrine hydrochloride and Pyridoxine hydrochloride. The method is based on the oxidation of 2, 4- Dinitro phenylhydrazine and coupling of the oxidized product with drugs to give intensely colored chromogen. Under the proposed optical condition, Beer’s law was obeyed in the concentration range of 2.5 - 30 µg mL-1and 5 – 20 µg mL-1 for Phenylephrine Hydrochloride and Pyridoxine Hydrochloride respectively. The limit of detection (LOD) and limit of quantification (LOQ) were 0.3, 1.95 µg mL-1 and 0.95, 0.64 µg mL-1 in the same order. No interference was observed from common pharmaceutical adjuvants. The suggested method was further applied for the determination of drugs in commercial pharmaceutical dosage forms, which was compared statistically with reference methods by means of t- test and F- test and were found not to differ significantly at 95% confidence level. The procedure is characterized by its simplicity with accuracy and precision.