Spectrophotometric Determination of Nitrazepam in Pharmaceutical Tablets Using Flow Injection Analysis

Nitrazepam (NZP) was determined spectrophotometrically in the pure form and in the pharmaceutical tablets using flow injection analysis (FIA). The method was based on oxidative coupling organic reaction of reduced NZP with promethazine hydrochloride in the presence of sodium periodate to give a green solution having an absorbance maximum at 613 nm. The various chemical and physical variables were optimized.The calibration graph of NZP is linear from 1 to 50 μg mL-1 with detection limit (S/N = 3) was 0.9284 μg mL-1. The method was successfully applied to the analysis of NZP in pharmaceutical tablets. The results obtained by applying the proposed FIA method were in good agreement with those obtained by British Pharmacopoeia method at the 95% confidence.