Cyclosporin derivatives and pharmaceutical compositions containing them

The present invention relates to novel cyclic peptides from the cyclosporine-series, the ability to inhibit the protein phosphatase calcineurin and therefore to have an immunosuppressive can be switched. It has been unexpectedly found that it is possible eliminate the effect of such immunosuppressive cyclosporine derivatives by modification of the hydroxyl group of a [D-Ser] Since therapeutically used doses of cyclosporin A have numerous unwanted side effects, the value of the present invention is that the immunosuppressive activity of the cyclosporin derivatives provided can be switched off. There is also the possibility that non-immunosuppressive cyclosporine derivative in a mixture with the parent compound or therapeutic use only. In therapeutic use of inventive switchable cyclosporine derivatives whose effect can be influenced during therapy.