Determination of enantiomeric purities using CD/CD detection

Engle, Allan R.; Purdie, Neil

doi:10.1016/0003-2670(94)00263-0

Cited by 12 publications

(12 citation statements)

References 15 publications

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“…Imprecisions based on data from three to five repeat measurements are an improvement by almost a factor of 10 over results obtained from the analyses of binary ephedrine mixtures in which a chemometric analysis method was applied to data at five wavelengths. 9 Despite the splitting of the YGG/yGG and the noise in the LGG/lGG plots, by using best-fit correlation lines, the agreements between calculated and measured EP's are still very good. The method is quantitatively valid over the full range of enantiomeric ratios from 100% L to 100% D. (b) GGA +"Chemical Impurity" Levels for All Other TripeptidessThe question with respect to "chemical impurities" that needs to be addressed is not how great the differences are between the curve for an 8.0 mM solution of GGA and curves for the other tripeptides at equimolar concentrations, Figures 2 and 3, but rather, are the differences sufficient enough to identify and quantitate anonymous chiral "chemical impurities" when these amount to only a few percent of the total composition of a binary mixture?…”

Section: Cu(ii)-peptide and D-histidine Complexessthe Local Microsymmmentioning

confidence: 95%

“…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%

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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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Section: Cu(ii)-peptide and D-histidine Complexessthe Local Microsymmmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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Tripeptide discriminations using circular dichroism detection

Purdie

Province

Johnson

1999

Journal of Pharmaceutical Sciences

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“…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%

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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“…15 Using multivariate regression analyses (MVRA) on data measured at several wavelengths, accurate results were obtained for EP for binary mixtures of the ephedrines. 16 The object of this article is t o test and evaluate the measurement of EP on the same binary analyte systems by multichannel polarimetry.…”

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confidence: 99%