Mark Abel

Synthesis of cyclosporin analogs

The invention is directed to isomeric mixtures of cyclosporine analogues that are structurally similar to cyclosporine A. The mixtures possess enhanced efficacy and reduced toxicity over the individual isomers and over naturally occurring and other presently known cyclosporines and cyclosporine derivatives. Embodiments of the present invention are directed toward cis and trans-isomers of cyclosporin A analogs referred to as ISATX247, and derivatives thereof. ISATX247 isomers and alkylated, arylated, and deuterated derivatives are synthesized by stereoselective pathways where the particular conditions of a reaction determine the degree of stereoselectivity. Stereoselective pathways may utilize a Wittig reaction, or an organometallic reagent comprising inorganic elements such as boron, silicon, titanium, and lithium. The ratio of isomers in a mixture may range from about 10 to 90 percent by weight of the (E)-isomer to about 90 to 10 percent by weight of the (Z)-isomer, based on the total weight of the mixture.

Study of FK-binding protein: FK506-metabolite complexes by electrospray mass spectrometry: correlation to immunosuppressive activity.

Electrospray ionization mass spectrometry was used to study several non-covalent FK-binding protein (FKBP) immunosuppressant complexes in the gas phase. Relative FKBP binding affinities were determined from the signal ratio for the 7+ charge states of bound and unbound complexes as a function of capillary exit voltage. All complexes displayed a 1:1 binding stoichiometry. The relative gas-phase binding affinities were found to be well correlated with in vitro FKBP binding and in vitro immunosuppression (rapamycin > FK506 > or = 31-demethyl FK506 > 13-demethyl FK506 >> Cyclosporin A; CsA). The method demonstrates potential as a simple, rapid, and automatable technique for prediction of the immunosuppressive activity of FKBP:drug complexes.