Spectrophotometric Determination of Nitrazepam by Coupling of it's Diazotized Reduced form with m- Aminophenol as Coupling Reagent

This paper describes the development of a spectrophotometric method for the determination of microgram amounts of nitrazepam after diazotization of its reduced product and coupling with m-aminophenol in basic medium, to form an intense orange coloured, water soluble and stable azo-dye which shows a maximum absorption at 478 nm. Beers law is obeyed over the concentration range of 5 to 200g/25ml with a molar absorptivity 17581.25 l. mol-1.cm-1 and Sandells sensitivity of 0.016 g.cm-2. The relative error is ranged from -2.11 to +1. 4% and relative standard deviation from 0.55 to 2.10 %, depending on the concentration level.
The method has been applied successfully to the determination of nitrazepam in pharmaceutical preparation (tablet).