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Spectrophotometric and spectrodensitometric methods for the determination of rivastigmine hydrogen tartrate in presence of its degradation product
Author(s) -
Salem Maissa Y.,
ElKosasy Amira M.,
ElBardicy Mohamed G.,
Abd ElRahman Mohamed K.
Publication year - 2010
Publication title -
drug testing and analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.065
H-Index - 54
eISSN - 1942-7611
pISSN - 1942-7603
DOI - 10.1002/dta.121
Subject(s) - chemistry , chromatography , dosage form , tartrate , methanol , analytical chemistry (journal) , inorganic chemistry , organic chemistry
Three sensitive, selective and precise stability‐indicating methods for the determination of the anti‐Alzheimer's drug, rivastigmine hydrogen tartrate (RIV) in the presence of its alkaline degradation product (major metabolite, NAP 226‐90) and in pharmaceutical formulation were developed and validated. The first method is a second derivative (D 2 ) spectrophotometric one, which allows the determination of RIV in the presence of its degradate at 262 nm (corresponding to zero crossing of the degradate) over a concentration range of 50–500 µg/ml with mean percentage recovery 100.18 ± 0.628. The second method is the first derivative of the ratio spectra (DD 1 ) by measuring the peak amplitude at 272 nm over the same concentration range as (D 2 ) spectrophotometric method, with mean percentage recovery 99.97 ± 0.641. The third method is a TLC‐densitometric one, where RIV was separated from its degradate on silica gel plates using methanol:butanol:H 2 O:ammonia (5:4:1:0.01 v:v:v) as a developing system. This method depends on the quantitative densitometric evaluation of thin layer chromatogram of RIV at 263 nm over a concentration range of 20–160 µg/spot, with mean percentage recovery 100.19 ± 1.344. The selectivity of the proposed methods was tested using laboratory‐prepared mixtures. The proposed methods have been successfully applied to the analysis of RIV in pharmaceutical dosage forms without interference from other dosage form additives and the results were statistically compared with reference method. Copyright © 2010 John Wiley & Sons, Ltd.