Using of Diazotized 2,4-Dinitroaniline in Spectrophotometric Estimation of Phenylephrine Hydrochloride

The suggested work included simple accurate diazo-coupling spectrophotometric method for the determination of phenylephrine-HCl (PHEPH) in pure drug and tablet formulation. The method was based on coupling of PHEPH with diazotized 2,4-dinitroaniline in alkaline medium. The sensitivity expressed by the value of molar absorptivity of yellowish-orange azo- dye was 1.915 104 L. mol-1. cm-1, the maximum absorption at 455 nm and Beer's law obeyed within the range of 10-200 g/10ml of PHEPH. The color of the product was highly stable and did not show a significant change in absorbance up to 60 min. with a recovery of 99.97% and a RSD% is 0.024%. The PHEPH in nose drop and syrup has been estimated with satisfactory results.