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- Norrman, Mathias, et al.
(författare)
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Characterization of insulin microcrystals using powder diffraction and multivariate data analysis
- 2006
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Ingår i: Journal of Applied Crystallography. - 1600-5767. ; 39, s. 391-400
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Tidskriftsartikel (refereegranskat)abstract
- Twelve different microcrystalline insulin formulations were investigated by X-ray powder diffraction and were shown to have very characteristic patterns. Three of the formulations crystallize in the same crystal system, but have structural differences in the N-terminal B-chain of the insulin molecule. This difference was efficiently detected in the powder patterns. The sensitivity of the method makes it a valuable tool for characterization of microcrystalline samples. By use of principal-component analysis, the twelve different formulations originating from six different crystal systems were classified into nine separate clusters. The powder patterns of each cluster can now be used as `fingerprints' for the different insulin polymorphs. The combination of X-ray powder diffraction and multivariate analysis, such as principal-component analysis, provides a rapid and effective tool for studying the influence of derivatives, additives, ions, pH etc., in the crystallization media.
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