Determination of Enantiomers in Ephedrine Mixtures by Polarimetry

Engle, Allan R.; Lucas, Edralin A.; Purdie, Neil

doi:10.1002/jps.2600830924

Cited by 8 publications

(9 citation statements)

References 13 publications

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“…KI at a concentration of 0.03 M was added as a stabilizer. 9,10 Working solutions were prepared by diluting the stocks by a factor of ten with 0.10 M NaOH.…”

Section: Solution Preparationsmentioning

confidence: 99%

“…The experimental procedure is a simplification of the method that was used to measure EP's for ephedrine mixtures. 9,10 Data reduction and spectral differentiations are done using variations on standardized mathematical algorithms.…”

Section: Introductionmentioning

confidence: 99%

“…By combining multiple wavelength detection with modern chemometric methods for data analysis, a third alternative procedure was described. 9,10 The procedure exploits the best characteristics of both of the other methods; use of a single chiral detector; bulk in situ derivatizations; no separation step(s). Results obtained for the determinations of EP's using visible CD detection for the four ephedrine stereoisomers complexed to Cu(II) ion, were an improvement over what was capable at that time by either the chiral chromatographic or two-detector methods.…”

Section: Introductionmentioning

confidence: 99%

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Algorithms for the quantitative validation of chiral properties of peptides

Purdie

Province

1999

Chirality

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Complexation with Cu(II) ion in strong aqueous base, combined with visible range circular dichroism detection, were used to quantitatively differentiate among the L‐enantiomers of the GG, GA, GY, AG, AA, AY, YG, YA, and YY dipeptides and the D‐enantiomer of GA. Using ellipticity data at all (n = 1500) wavelengths in the measured spectra, and two novel data reduction procedures, quantitative determinations were made of the compositions of binary mixtures. For mixtures made with the L‐GA and D‐GA enantiomers, the accuracy of the measured enantiomeric purities was better than 0.17 % over the 1–48 % range for the minor component. The method has considerable potential for use in quality control of peptide and protein biotechnological drug forms. Chirality 11:546–553, 1999. © 1999 Wiley‐Liss, Inc.

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“…KI at a concentration of 0.03 M was added as a stabilizer. 9,10 Working solutions were prepared by diluting the stocks by a factor of ten with 0.10 M NaOH.…”

Section: Solution Preparationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Algorithms for the quantitative validation of chiral properties of peptides

Purdie

Province

1999

Chirality

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“…9,10 The procedure exploits the best characteristics of both of the other methods, namely a single chiral detector, bulk in situ derivatizations, and no separations. Results obtained for the determinations of chemical and enantiomeric impurities using visible CD detection for binary mixtures of the four ephedrine stereoisomers complexed to Cu(II) ion were an improvement over what was capable at that time by either the chiral chromatographic or two-detector methods.…”

Section: Introductionmentioning

confidence: 99%

“…[9][10][11] Data reduction and spectral differentiations are done using variations on standardized mathematical algorithms and principal component analysis (PCA).…”

Section: Introductionmentioning

confidence: 99%

Tripeptide discriminations using circular dichroism detection

Purdie

Province

Johnson

1999

Journal of Pharmaceutical Sciences

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A general spectroscopic method is described that might be applied to validating amino acid sequences in peptides and protein fragments with a view to it becoming a routine procedure with which to characterize biotechnology drug products. The tripeptides are the L-enantiomers of GGA, GGH, GGI, GGL, GGF, GHG, LGG, and YGG. The simple procedure calls for their complexation with Cu(II) ion in strong aqueous base. Binding the first three residues in the sequence, beginning at the amine terminus, completes the coordination sphere of the Cu(II) ion, so duplication of the initial sequence from peptide to peptide could be an important limiting factor in determining the extent of differentiation that is possible. The analytical focus is the selectivity associated with the chirality properties of the peptides. Detection is by circular dichroism operating in the visible range. The eight analytes were chosen as representative of a series where the sequences are most similar and therefore potentially the most difficult to discriminate spectroscopically. All have just one chiral center. Using ellipticity data at all (n = 1500) wavelengths in the measured spectra, and two novel data reduction procedures, total discrimination among all eight analytes is achieved. The method has considerable potential for use in quality control of peptide and protein biotechnological drug forms, especially their enantiomeric purities.

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Ephedra in perspective – a current review

Abourashed

El‐Alfy

Khan

et al. 2003

Phytotherapy Research

227

173

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Although the traditional use of Ephedra 'ma huang' has been established for thousands of years, its resurgence in the US as a herbal dietary supplement is currently a matter of national controversy. At the heart of the debate are three important questions: (1) the identity and composition of Ephedra products with regard to ephedrine and related alkaloids; (2) the potential therapeutic utility of Ephedra supplements for weight loss or performance enhancement; and (3) potential health risks associated with such uses of Ephedra, particularly in sensitive individuals or in cases of intentional abuse for its stimulant properties. This review surveys the literature on Ephedra with regard to traditional uses, botany, chemistry, analytics, pharmacological effects and health risks. A brief discussion of the central issues in the current debate on the regulation of Ephedra in the United States is included as this is where most of the problems have occurred to date.

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Determination of Enantiomers in Ephedrine Mixtures by Polarimetry

Cited by 8 publications

References 13 publications

Algorithms for the quantitative validation of chiral properties of peptides

Algorithms for the quantitative validation of chiral properties of peptides

Tripeptide discriminations using circular dichroism detection

Ephedra in perspective – a current review

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