ISSN:
1612-1112
Schlagwort(e):
Column liquid chromatography
;
Cyclosporin
;
Reversible conversion
;
Activation energy
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Summary Reversed-phase liquid chromatography of cyclosporin A, a peptide immunosuppressant, at various temperatures produced remarkably different chromatograms. At 60°C one sharp peak was obtained, at 23°C this became a single broad peak and between 15° and 0°C this became one high sharp peak followed by a tailing or low plateau. Remarkably different chromatograms were produced also by varying the mobile phase flow-rate. The effects of both temperature and flow-rate on the chromatogram could be accounted for by interconversion between two forms of the cyclosporin molecule. Kinetic analysis showed that one form was converted by first-order kinetics with a half-life of 2.0 min at 20°C and that the apparent activation energy for the conversion was about 18 kcal/mol. The other two immunosuppressants, cyclosporin C and D, were also shown to undergo interconversion. This kinetic analysis of the interconversion should be helpful in clarifying the relationship between molecular structure and activity of the immunosuppressants.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF02269781
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