Iloprost is a second generation structural analog of prostacyclin (PGI2) with about ten-fold greater potency than the first generation stable analogs, typified by carbaprostacyclin. Iloprost binds with equal affinity to the recombinant human IP and EP receptors with a Ki of 11 nM. 15(R)-Iloprost is the “unnatural” or inverted C-15 epimer of iloprost. This transformation frequently attenuates the biological agonist activity of prostaglandin analogs by several orders of magnitude. There are no literature reports of the biological activity of 15(R)-iloprost.
