H. D. Revanasiddappa, H. N. Deepakumari, S. M. Mallegowda and K. B. Vinay
Development
and Validation of Spectrophotometric Methods for Nitrazepam in Pure and the
Tablet Dosage Form
Abstract
Two simple, sensitive, accurate and reproducible spectrophotometric
methods have been described for the assay of nitrazepam (NTZ) in both pure and
in pharmaceutical preparations using β-naphthol and p-dimethyl amino benzaldehyde (PDAB)
as chromogenic agents. The first method is based on the diazo-coupling reaction
of reduced nitrazepam with β-naphthol
(Method A) and the second one is based on the condensation reaction of primary
aromatic amine group of reduced nitrazepam with aromatic aldehyde PDAB to
yield yellow colored Schiff’s base (Method B). The formed products show
maximium absorption at 500 and at 440 nm for methods A and B, respectively.
Beer’s law was obeyed in the concentration range of 0–40.0 and 0–5.0 µg/ml for
methods A and B, respectively and the corresponding molar absorptivity values
are 6.49×103 and 5.13×104 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 excipients normally added to the tablets. The
proposed methods are simple, sensitive, rapid and economical, and could find
application as in routine quality control analysis for nitrazepam.
Key words: diazo-coupling, Schiff’s base, spectrophotometry, nitrazepam,
pharmaceuticals.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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