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 EP1 receptors with a Ki value of 11 nM. Most preparations of iloprost contain 16(S) and 16(R) stereoisomers. 16(S)-Iloprost potently inhibits platelet aggregation with an IC50 value of 3.5 nM.
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 EP1 receptors with a Ki value of 11 nM. Most preparations of iloprost contain 16(S) and 16(R) stereoisomers. 16(R)-Iloprost inhibits platelet aggregation with an IC50 value of 65 nM.
Epoxyeicosatrienoic acids (EETs), such as 11(12)-EET and 14(15)-EET, are cytochrome P450 metabolites of arachidonic acid that have been identified as endothelium-derived hyperpolarizing factors with vasodilator activity. 14,15-EE-5(Z)-E is a structural analog of 14,15-epoxyeicosatrienoic acids (14,15-EET) that antagonizes EET-induced relaxation of vascular smooth muscle. Relaxation of U46619-constricted bovine arteries by 14,15-EET could be inhibited approximately 80% by 14,15-EE-5(Z)-E at a concentration of 10 μM. 14,15-EE-5(Z)-E does not appear to antagonize nitric oxide- or iloprost-mediated vascular relaxation.
BMY-42393 is orally active and selective platelet aggregation inhibitor. BMY-42393 is also a prostacyclin partial agonist that inhibited ADP, collagen and thrombin-induced platelet aggregation (IC50 range 0.3 - 2.0 microM). BMY-42393 stimulated platelet adenylate cyclase activity (EC50 = 25 nM). Platelets treated with BMY 42393 showed an elevation of cAMP levels and activation of cAMP-dependent protein kinase. BMY 42393 also inhibited thrombin-induced elevation of intracellular free calcium. BMY 42393 competed for radiolabeled iloprost and PGE1 binding to platelet membranes (IC50; 170 nM and 130 nM, respectively).