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Journal of Spectroscopy
Volume 2013, Article ID 671689, 8 pages
Research Article

Spectrophotometric Estimation of Nitrazepam in Pure and in Pharmaceutical Preparations

Department of Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India

Received 27 June 2012; Revised 22 August 2012; Accepted 24 August 2012

Academic Editor: Jeongkwon Kim

Copyright © 2013 Hemavathi Nagaraju Deepakumari and Hosakere Doddarevanna Revanasiddappa. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Three simple, sensitive, accurate, and rapid visible spectrophotometric methods (A, B, and C) have been developed for the estimation of nitrazepam in both pure and in pharmaceutical preparations. They are based on the diazotization of reduced nitrazepam with nitrous acid followed by coupling with acetyl acetone (method A), diphenylamine (method B), and citrazinic acid (method C) to form colored azo-dyes, exhibiting absorption maxima ( ) at 400, 550, and 460 nm, for methods A, B, and C, respectively. The produced colored azo-dyes are stable for more than 2 h. Beer's law was obeyed in the concentration range of 0.5–20, 0.3–14 and 0.5–12 μg/mL for methods A, B, and C, respectively and the corresponding molar absorptivity values are , , and  L mol−1cm−1. All variables have been optimized and the results were statistically compared with those of a literature method by employing the Student's t-test and F-test. No interference was observed from common adjuvants normally added to the tablets. The results obtained in the proposed methods are in good agreement with labeled amounts, when marketed pharmaceutical preparations are analyzed, which could be applied in the routine quality control analysis laboratory.