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CE assay for simultaneous determination of charged and neutral impurities in dexamphetamine sulfate using a dual CD system
Author(s) -
Wongwan Sudaporn,
Sungthong Bunleu,
Scriba Gerhard K. E.
Publication year - 2010
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200900724
Subject(s) - chemistry , ephedrine , chromatography , analyte , impurity , electrolyte , oxime , sodium sulfate , sodium , organic chemistry , electrode , neuroscience , biology
A CE assay for the simultaneous determination of charged and uncharged potential impurities (1 S ,2 S ‐(+)‐norpseudoephedrine, 1 R ,2 S ‐(−)‐norephedrine, phenylacetone and phenylacetone oxime) of dexamphetamine sulfate including the stereoisomer levoamphetamine was developed and validated. The optimized background electrolyte consisted of a 50 mM sodium phosphate buffer, pH 3.0, containing 80 mg/mL sulfobutylether‐β‐CD and 25 mg/mL sulfated β‐CD. Separations were performed in 40.2/35 cm, 50 μm id fused‐silica capillaries at a temperature of 20°C and an applied voltage of –10 kV. 1 R ,2 S ‐(−)‐ephedrine was used as internal standard. The assay was validated in the range of 0.05–1.0% for the related substances and in the range of 0.05–5.0% for levoamphetamine. The LOD was 0.01–0.02% depending on the analyte. The assay also allowed the separation of the E,Z‐stereoisomers of phenylacetone oxime. The effect of the degree of substitution of sulfobutylether‐β‐CD was investigated. In commercial samples of dexamphetamine sulfate between 3.2 and 3.7% of levoamphetamine were found. Furthermore, phenylacetone and phenylacetone oxime could be observed at the LOD, indicating the synthetic origin of the investigated samples.