New Colorimetric Methods for Microdetermination of Melatonin in Pure and in Dosage Forms
作者:
A.S. Amin,
M. Zaky,
H. M. Khater,
A. M. El-Beshbeshy,
期刊:
Analytical Letters
(Taylor Available online 1999)
卷期:
Volume 32,
issue 7
页码: 1421-1434
ISSN:0003-2719
年代: 1999
DOI:10.1080/00032719908542907
出版商: Taylor & Francis Group
关键词: Melatonin;pharmaceutical formulation;1,10-phenanthroline;2,2-Bipyridyl, colorimetric.
数据来源: Taylor
摘要:
Two simple, rapid, sensitive and accurate methods (A and B) for the microdetermination of melatonin in pure form and in pharmaceutical formulations are developed. Method A is based on the formation of tris(o-phenanthroline)iron(II) complex (ferroin) upon reaction of melatonin with an iron(III)-o-phenanthroline mixture in sodium acetate-acetic acid buffer media. The ferroin complex is colorimetrically measured at λmax510 nm against reagent blank. Method B is based on the reduction of Fe (III) by the drug which forms a colored complex (λmax522 nm) with 2,2-bipyridyl. Optimizations of the experimental conditions are described. Beer's law is obeyed in the concentration range 0.4 – 6.4 μg ml−for A and 0.4 – 7.4 μg ml−for B, respectively. The developed methods are applied successfully for the determination of melatonin in pure form and in melatonin tablets without any interference from common excipients.
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